Analog Synthesis: The Newbie Guide to Synthesizers and Sound-Design [2 ed.] 3934903010, 9783934903012

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Reinhard Schmitz Analog Synthesis

Reinhard Schmitz

Analog Synthesis The Newbie Guide to Synthesizers and Sound Design

w

Author

Reinhard Schmitz

Translation Tom Green Cover art M0type, www.motype.de Interior design & layout Uwe Senkler © 1999–2005 Wizoo Publishing GmbH, www.wizoobooks.com ISBN

3-934903-01-0

All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means, including information storage and retrieval systems, without permission in writing from the publisher. All product names and company names mentioned in this book are either trademarks or registered trademarks of their respective owners.

Welcome It must have been around 1975 when I first locked horns with that mysterious beast, the synthesizer. The keyboardist of the band I was in at the time had bought a second-hand ARP Odyssey. Perched atop a Fender Rhodes in our rehearsal room, this sheet metal incarnation of man’s dream of a bigger and better sonic spectrum seemed to have just one hitch —it was as mute as a stone effigy. Failing to coax any kind of sound out of it, the case was clear: our ivory tickler had been had! For some unfathomable reason, the unspoken consensus in this particular combo was that the guitarist—me that is—was responsible for technically challenging chores such as soldering cords, replacing fuses, defrosting the fridge etc., so I was elected to find the ghost in the machine. And after just two hours of man-handling the box’s faders to come up with every conceivable combination of settings, I found the culprit: the slider for the cutoff frequency of the filter was pulled all the way down. Go figure. Anyway, the synth squawked away merrily and the rest is history. No worries, in all enthusiasm, I am not going to bore you with a gripping yarn about a man and his metal machine mistresses, but henceforth it was a clear case of “romancing the synth.” Why am I sharing this wonderful little anecdote with you? Only to make it clear to you that people who are perceived as gurus—by others or themselves—and share their profound wisdom in books about synths such as this one didn’t have a clue when they started out. So don’t sweat the small stuff and definitely forget about being intimidated by the many knobs and switches. Think of all of those little gizmos as your allies in the never-ending struggle against boring sounds.

On the flip side, it really is helpful if you have a general idea of what will happen when you tweak this parameter or twiddle that knob, or like me in my newbie days, what won’t happen if you don’t. Presumably, you bought this book because you are raring to wade right into the wonderful world of analog sound synthesis and get your feet wet with some experimentation. And that’s precisely what this book was written for, to help you avoid hassle, headaches and grief and get down to the nitty-gritty of making metal machine music. Much of the fun of dabbling in analog synthesis is Zen-like: the path to gaining knowledge can be as exciting as your ultimate destination. In this spirit, I hope you enjoy discovering this world as much as I did being your guide.

Reinhard Schmitz

Contents 1 Synthesizer Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Exactly Is a Synthesizer? . . . . . . . . . . . . . . . . . . . . . . . . . . . Synthesizer History 101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Theremin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spherophone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ondes Martenot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trautonium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hammond Organ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mixturtrautonium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Forerunner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The First Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Is an Analog Synthesizer? . . . . . . . . . . . . . . . . . . . . . . . . . .

11 11 11 11 12 13 14 15 16 17 18 18 19

2 How Many Species of Analog Synthesizers Are Out There? Modular Synthesizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hard-wired Synthesizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Real Analog Vs. Virtual Analog Debate . . . . . . . . . . . . . . . . .

23 23 26 28

3 What Analog Sound Synthesis Can and Can’t Do . . . . . . . Understanding Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How Is an Analog Sound Generated? . . . . . . . . . . . . . . . . . . . . . . Is an Analog Synthesizer a Gifted Mimic? . . . . . . . . . . . . . . . . . . The Basic Components of Analog Sound Generation . . . . . . . . .

31 31 32 35 36

4 Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oscillator Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39 39 44

7

Contents

Combining Oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44 45

5 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Filter Settings: Cutoff and Resonance . . . . . . . . . . . . . . . . . . . . . . What Types of Filters Are There? . . . . . . . . . . . . . . . . . . . . . . . . . . Combining Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The “Sound” of a Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

49 50 51 55 55 57

6 Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

7 Envelopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Does an Envelope Do? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Type of Envelopes Can I Play With? . . . . . . . . . . . . . . . . . . Where Can I Use Envelopes? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Are there “Good” and “Bad” Envelopes? . . . . . . . . . . . . . . . . . . . .

61 61 62 64 67

8 LFOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 LFO Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 What Do the Different LFO waveforms Do? . . . . . . . . . . . . . . . . . 70 Controlling the LFO Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Delaying and Fading LFOS In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 LFO Retrigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Using Several LFOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Which LFO Setting Generates Which Effect? . . . . . . . . . . . . . . . . 75 9 Playing and Controlling Synthesizer Sounds . . . . . . . . . . . . Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79 79 85 89

10 Advanced Synthesis Features and Gear . . . . . . . . . . . . . . . . 95 Using an Oscillator as a Modulator . . . . . . . . . . . . . . . . . . . . . . . . 95 Using Your Synthesizer as an Effects Device . . . . . . . . . . . . . . . . 96 Envelope Follower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Pitch-to-Voltage Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8

Contents

Sample & Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Formant Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vocoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step Sequencers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Types of Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Wo)Man as Modulator—“Playing” Sounds . . . . . . . . . . . . . . . . .

97 98 99 101 105 112

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Contents of the Audio CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pocket Compendium of Analog Sound Synthesis . . . . . . . . . . . .

115 115 117

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

125

9

11 Synthesizer Basics What Exactly Is a Synthesizer? For our purposes, a synthesizer is a device equipped with electronic circuitry designed to generate sound and noise. These artificially “synthesized” (hence the imaginative name) sounds or noises can be imitative, i.e. replications of known sounds such as those produced by acoustic instruments, bird calls or the sound of pounding surf, or completely novel, previously unheard of sounds not found in nature (provided of course that you call the Earth home).

Synthesizer History 101 The origins of the synthesizer don’t date back quite as far as Genesis, but astonishingly, to the latter half of the previous century. Daring men braved great dangers to convert electricity into music using all manner of diabolical devices, some practical, others wildly improbable. Initially, many of these visionaries were attempting to create a new musical aesthetic with their unusual instruments. In time however, the imitative capabilities of electronic sound generators were recognized by musicians and inventors, and were in the end responsible for the commercial breakthrough of the down-sized version of these behemoths.

Dynamophone In 1906, the US inventor Thaddeus Cahill built the Dynamophone, also known as the Telharmonium. This 200-ton monstrosity resembled a goodsized machine factory and generated pulses using electromagnetic generators. When Thaddeus “played” his tunes, these impulses were piped into

11

1 Synthesizer Basics

the telephone network—speakers hadn’t been invented and radio was literally still out there in the ether—and converted into sound by telephone receivers. Subscribers to the telephone network were unenthusiastic. Whenever Thaddeus got the urge to play a little ditty, massive complaints were the norm. The interference generated by the Dynamophone “broadcasts” tended to be rather annoying when people were attempting to chat over Alexander Graham Bell’s hobby horse and eventually spelled extinction for the dynamo-driven dinosaur. Dynamo Hum indeed (apologies to Frank half-tone).

Theremin a100ther.tif

Theremin module of the Doepfer system A-100

In 1920, the Russian inventor Leon Theremin introduced an instrument which was later also known as Thereminvox and Etherophone, and much, much later was actually featured in a chart-topping hit by the Beach Boys, the appropriately titled Good Vibrations. The Theremin didn’t have what you might call a high-tech look, it was simply a box with two antennas. Its plumbing was fairly rudimentary as well; it came complete with two battery-fed high-frequency generators which did just that, generate sound. At some 300 kHz, its frequencies were well

12

Spherophone

outside the range of human hearing, but these were patched through a modulator and a low pass filter. This produced a lower frequency equal to the difference in their rates of vibration—it was audible when routed to a speaker. One of the generators worked with a fixed, the other with a variable frequency. The latter was connected to an antenna, which allowed you to maniacally wave your right hand in an electrostatic field: The closer your hand moved to the antenna, the higher the pitch, the further away, the lower the pitch. The box included a switch that let you roughly preselect the volume level. This gadget could actually be “played” by moving your left hand over a second loop-shaped antenna located on the left-hand side of the device. Older musicians (like me) might recall Led Zeppelin riff meister Jimmy Page and his bizarre Theremin antics on the proto-metal grunge fest Whole Lotta Love.

Spherophone In 1926, the music world was treated to another milestone on the road to the synthesizer, the Spherophone. The father of the apparatus was Jörg Mager, a teacher, organist and sometime laborer in a radio factory. Mager sought to create what he considered the ideal instrument—infinitely variable pitch being his ultimate goal. The Spherophone, like the Theremin, was a beat-frequency audio oscillator: Two high-frequency generators produced an audible frequency equivalent to the difference in their rates of vibration. To manipulate pitch, Mager installed a variable capacitor in one of the two resonant circuits. The variable capacitor had a winder attached to it. When you literally “cranked” this gadget, it moved along a semicircular trajectory patterned on the steps of the chromatic scale. By turning the crank, one was actually changing the capacitance and thus the pitch. To mute the at times unwanted audible glide produced by the variable capacitor when one tone was followed by the next, the device featured another crank to preselect the next note. The instrument also produced different timbres or tonal colors which were generated by filter banks.

13

1 Synthesizer Basics

A five-voice successor to the Spherophone, the Partiturophone, premiered in 1931 at the Bayreuth Festival. It was used to emulate Wagnerian hell’s bells electronically—an early breakthrough in using electronic instruments to imitate natural sounds. Mager’s instruments, including the Caleidophone, an instrument that he built later, fell victim to the inhospitable political climate in post-1933 Germany and were all but forgotten in the wake of the imminent war.

Ondes Martenot In 1928, the strains of the Ondes Musicales, an apparatus masterminded by Frenchman Maurice Martenot, were heard publicly for the first time in the Paris Opéra. Designed with the rather modest goal of imitating the sound of all conventional instruments, the instrument won recognition from numerous renowned composers, including Milhaud, Ravel, Honnegger, Messiaen and Varèse. Renamed Ondes Martenot, it became a notable commercial success. In many theaters, particularly in France, the Ondes was used to perform the music for plays etc. Martenot’s customers weren’t limited to cultural institutions such as the Opéra National, even revue theaters such as the Folies Bergères bought his innovation. Martenot’s instrument operated along much the same lines as the Theremin and Spherophone: oscillating radio tubes produced electric pulses. Although later versions featured an actual keyboard, earlier incarnations had a mock keyboard that was no more than a visual guide to help players identify pitches. It wasn’t until 1947 that the instrument was sold with a conventionally “playable” keyboard. Previously, a wire attached to a variable capacitor was stretched across the fake keyboard. To play this instrument, you had to insert your index finger into a loop attached to the wire and pull the wire back and forth, which changed the capacitance and thus the pitch.

14

Trautonium

The tones generated by this method had a distinct disadvantage—they didn’t have any attack or release time to speak of. They started suddenly and ended equally abruptly—instantly in and out of your face so to speak. To make his instrument musically viable, Martenot included a voicing section. For this purpose, your left hand could manipulate the register lever via a slider located on the left side of the instrument. The twelve timbre registers of the Ondes could also be selected via this slider.

Trautonium In 1930, another breakthrough in the evolution of electronic musical instruments saw the light of day, the Trautonium. The device was the brainchild of Friedrich Trautwein, an engineer, musicologist and organist. The avid support of the director of the Academy of Music in Berlin and the companies Telefunken and AEG presumably didn’t hurt the project. Asked in an interview what he was attempting to achieve by building an electronic instrument, Trautwein noted that he sought to “offer new possibilities for expression to the creative artist” and believed that his efforts would “particularly serve creative artistry and thus help reconcile the wrongly polarized branches of the human spirit: art and technology.” Admirable words, and certainly ones that you wouldn’t expect to hear from designers of modern synthesizers. The Trautonium was a modest hit. Among the composers who wrote specifically for the Trautonium were illustrious names such as Paul Hindemith, Richard Strauss and Werner Egk. Trautwein’s instrument featured a radio tube-based low-frequency generator that produced sawtooth-shaped deflective oscillations. The tube circuit was wired in parallel to a capacitor, which was charged periodically via a three-pole tube. The tube’s grid bias—variable via a set of push-buttons— determined the amount of discharges and thus the pitch.

15

1 Synthesizer Basics

Rather than equip his design with a conventional keyboard, Trautwein chose an invention patented a few years earlier by colleagues from Frankfurt. He strung a steel wire over a steel bar that indicated scale intervals. One could vary the frequency by pressing the wire onto the bar kind of like playing an—albeit huge—single-string violin, without a bow of course. A carbon resistor converted the amount of pressure placed on the wire to an electrical value, which in turn determined the dynamics of the tone. In 1932, the company Telefunken began building an in several technical details improved version of the Trautonium, whereby different sources quote the number of manufactured units anywhere from 50 to 100. Thus this device can rightfully be termed the first electronic instrument manufactured industrially. Trautwein also integrated circuits that controlled the timbre of the generated tones: The oscillations of the generator tube, rich in harmonics, were routed to two electrical resonance circuits in which some frequencies were filtered out, others amplified. The Telefunken model featured twelve rotary knobs and push-buttons which controlled the timbre, octave transposition and tonal range.

Hammond Organ In Chicago in 1934, Laurens Hammond invented an organ based on the principle of Cahill’s antiquated oddity. It soon became the first electronic instrument to be mass produced. The rest, as they say, is history: the Hammond Organ was a worldwide success, in musical as well as commercial terms.

16

Mixturtrautonium

Mixturtrautonium Sala-02

The Trautonium of the great Oskar Sala

In 1952, the erstwhile Trautwein assistant and Hindemith student Oskar Sala, who had in the meantime become the leading concert soloist on the Trautonium, introduced his polyphonic version of the instrument, what he called the Mixturtrautonium. Initially featuring two voices and later four, this new and improved version placed a notably wider tonal spectrum in the hands of musicians. For example, Sala equipped his design with a noise generator to do just that, an electronic interrupter for creating rhythmic effects as well as an “effects section” for reverb. Virtually everyone who owns a TV has at some point heard the Mixturtrautonium: The sound effects of Alfred Hitchcock’s classic “The Birds” were created by Sala on this instrument in 1962.

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1 Synthesizer Basics

The Forerunner In 1955, Radio Corporation of America (RCA) introduced a new product of awesome proportions, the Electronic Music Synthesizer. Its designers, Harry F. Olson and Herbert Belar, didn’t come up with what is today considered a synthesizer; the machine was actually a semi-automatic music generator: The composer wrote his musical ideas on an input mechanism resembling the keyboard of a telex machine, this information was then punched into a roll of paper tape. The machine read the punched paper tape and converted the data into music. These signals were routed to a six-track recorder via an amplifier and then pressed onto a record. Its sound generation system consisted of twelve sine oscillators, each of which rendered a fixed frequency of the chromatic scale from F# to F. A selector switch provided access to a tonal range of eight octaves. The initial sine oscillation of the tone generator was routed through a circuit that converted it into a sawtooth waveform rich in harmonic overtones. Other circuits within the envelopes served as envelope and noise generators, lowfrequency modulators for creating vibrato and tremolo, filter and resonator chains for generating different timbres, as well as level controls for manipulating volume. The everything-but-the-kitchen-sink profusion of dozens of tubes and hundreds of coils, transistors, relays, resistors and capacitors was housed in seven cabinets! We can safely assume that it wasn’t designed for gigging.

The First Synthesizer In 1964, US innovator Robert Moog presented a prototype of an electronic instrument at the AES; it was the ancestor of all devices that are classed as true analog synthesizers. Although Moog’s compatriot Don Buchla had introduced a similar system earlier, Moog was the first to use a control voltage of 1 volt/octave for all parameters. This remains the standard for analog synthesizers to this day.

18

What Is an Analog Synthesizer?

What Is an Analog Synthesizer? The term “analog synthesizer” has more to do with what type of components make up the device and how they were implemented rather than a description of the sounds it generates or how it generates these sounds. Oberheim xa

An inside look at the Oberheim OB-Xa: Despite the many integrated circuits, there it still boasts analog hardware aplenty.

If you wanted to be a purist about it, you could say that a true analog synthesizer works with circuits that consist of analog components such as transistors, resistors and capacitors. As digital technology began its campaign of world domination, synthesizers weren’t spared. Gradually ever more components were replaced by integrated circuits, microchips and finally, digital signal processors (DSPs).

19

1 Synthesizer Basics

What hasn’t changed a bit despite the digital revolution is the principle of sound generation behind the very first, very analog synthesizers. This principle is called—in technically correct terms, as you’ll see a bit further on in the book—“subtractive synthesis,” but was given the misnomer “analog synthesis” a long time ago and the name stuck. At this point, you should give the first audio example a listen. It features archetypical analog synthesizer sounds and phrases, which should pretty much answer the question, “What does an analog synthesizer sound like?” CD track 01: Typical sounds and phrases of analog synthesizers: Moog Lead, Moog Sequenzer Bass, Modular Arpeggio, OB Dark Poly, OB Rock Poly, Modular SynthBrass, OB GlideDrone, Moog MegaBass, OB Warm Pad Polymoog

The first polyphonic Moog synthesizer, the Polymoog. Not a monster sales success, but certainly a classic design.

20

What Is an Analog Synthesizer? ob_ob8

A polyphonic legend. To this day, many synth freaks feel the Oberheim OB-8 is synonymous with fat analog sounds.

Jupiter 8

The Japanese competitor to the OB-8: The Roland Jupiter-8 is another polysynth that, in its heyday, set standards.

21

2 How Many Species of Analog Synthesizers Are Out There? Like virtually everything else in life, you can class analog synthesizers in ever diminishing categories. But to make it easy on yourself, forget about all the hair-splitting differentiation and think of every synth as a member of one of two tribes: modular or hard-wired synthesizers.

Modular Synthesizers A modular synthesizer is essentially a hodge-podge of more or less autonomous components called modules that feature anything from one to scores of input(s)/output(s) for all kinds of different signals. You have to connect the output of one module to the input of the another ad infinitum to DIY this collection of individual modules and conjure up a functional synthesizer circuit. By far the most popular method of connecting modules is to use patch cords. Patch cords are nothing more than cables with plugs at both ends, which are inserted in the jacks of the modules you plan on using. A less common technique of connecting the inputs and outputs of modules is to use a matrix patchboard. In this type of setup similar to a patchbay, the inputs and outputs are wired together internally and arranged in a matrix of jacks. You can establish a connection between jacks by inserting special plugs. The modular synthesizers built by the company EMS feature this type of module “erector kit.”

23

2 How Many Species of Analog Synthesizers Are Out There?

Even more exotic is the matrix switch system—to be honest, the only device that comes to mind featuring this rare beast is the ARP debut synth model 2500 built in 1970. In a switch matrix, the signal circuits of modules are assigned to rows of sliding switches. Depending on the slider settings, the assigned signal is routed to the inputs or outputs of other modules. Aufmacher.frei

A large modular system looking pretty tidy without a profusion and confusion of cables.

Inherently, modular synthesizers are a curse as well as a blessing. On the upside, you have practically unlimited signal routing flexibility, on the downside, handling is an abject nightmare. To come up with some semblance of sensible synth—you may after all want to generate something other than nerve-racking cacophony—you have to know a great deal about the nuts and bolts of synthesis.

24

Modular Synthesizers

Then of course there is the dreaded spaghetti syndrome—if you’re working with a system featuring patch cords, it at times takes a touch of clairvoyance to discern the convoluted twist and turns of signal flow. Even experts are occasionally stumped when working with complex configurations. However, there is some good news. Handling modular synthesizers in practice doesn’t take a photographic memory, because nearly all synths are hard-wired internally. This means you can connect modules freely, but you don’t have to. So if you ever find yourself coveting an older modular system such as the Roland System 100, Korg MS 20 or ARP 2600—by the way, I’ve consciously avoided mentioning the more astronomically priced models— have no fear: In principle, you can plug-n-play without touching a single patch cord. However, bear in mind that if you have a serious Jones for one of these fossils and you actually buy one, you may end up spending more time catering to the unpredictable whims of the machine rather than actually making music. Clavia Nord Modular

This is what a modern modular synthesizer looks like. The Clavia Nord Modular’s cords and modules are virtual, polyphonic and storable.

25

2 How Many Species of Analog Synthesizers Are Out There?

To say that vintage modular synthesizers are extremely volatile is an understatement; they are inherently conducive to faults. These boxes are chock full of hardware jacks and switching contacts that don’t respond particularly well to the working conditions of modern musicians (cigarette and sundry other smoke, beverage spillage, the wildly divergent temperatures and steamy window humidity of typical rehearsal rooms etc.). It won’t take much for these components to fail altogether; finding someone qualified to repair or locate replacement parts for your cherished squawk box is akin to a search for the Holy Grail. Not to mince words, if you are in the market for a modular synth, my recommendation is to absolutely, definitely, unequivocally go for a new model such as the Doepfer A100, Clavia Nord Modular, Native Instruments Generator or CreamWare Pulsar. Particularly the last three have a distinct advantage: They all emulate analog sound synthesis digitally (not as huge a contradiction as you might presume), so you can save sounds. Once you have plugged cords and tweaked knobs so that you finally come up with that killer sound, you can simply store the configuration and call it up whenever you need it—instantly and without the hassle of juggling dozens of cords.

Hard-wired Synthesizers Hard-wired synthesizers, also originally called “compact synthesizers,” are a step up from modular synths in the evolutionary chain of electronic musical instruments. The notion that inspired these lite versions is fairly simple: “Hey, why don’t we make a cheaper, more portable synthesizer to address a wider target group, sell a bevy of these and retire to that South Seas hideaway?” The solution was just as simple as it was ingenious: Take a limited number of synthesizer components and wrap a less gargantuan housing around them. The granddad of this breed of synths was the Moog Minimoog, released in 1970. Shortly after it hit stores, this little box took the synthesizer market by storm and managed to maintain its domination for the next decade or so. By the time the last units rolled off the production lines in 1981, 13,252 Minimoogs had been built—a staggering amount for those days.

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Hard-wired Synthesizers Synthesizer von gestern, Band 1

The definitive analog classic: Moog Minimoog

The majority of synthesizers produced in the wake of the Minimoog were in principal hard-wired—you couldn’t change their architecture without a soldering iron, a degree in electronic engineering and unchallenging day job. As players became more discerning and digital components more popular, most manufacturers made certain parameters—typically LFOs and envelopes—freely assignable. Players had the option of choosing which section of the synthesizer these parameters would influence. Compared with modular systems, the disadvantage of hard-wired synthesizers is glaringly obvious—they are substantially less versatile. On the upside, they are much easier to understand and handle. The fact that you can’t reconfigure components—or at least not by any remarkable measure—makes a hard-wired synth a piece of cake to deal with. Once you have figured out how a particular synthesizer does its thing, you can until the end of time handle it in the same manner. A modular system, like many a musician’s mood swings, is ever changing. Depending on how you connect modules, you may have to tame a different beast altogether.

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2 How Many Species of Analog Synthesizers Are Out There?

The Real Analog Vs. Virtual Analog Debate Over the past years, the question of which is better has been a hotly contested topic among synth freaks all over the world, and I’d be shirking my duties as your guide to analog sound synthesis if I didn’t comment on this controversial subject. Although we’ll join the fray fairly early in this book, this doesn’t mean that I consider the question particularly justified or even all that relevant. In truth, the priority I’ve given the question is a concession to the amount of times that it is asked. The fact of the matter is that a real analog synthesizer is based on the principle of subtractive synthesis and generates sounds using real analog components. A virtual analog synthesizer generates sounds via software that emulates analog components and the principle of subtractive synthesis. If competent programmers gave their all in designing an emulation, then the results of the two methods of sound generation are indistinguishable, at least in terms of adjectives such as “better” and “worse,” to quote just few of the less colorful terms that fly when the opposing camps collide. To me, there seems to be a basic flaw in people’s reasoning when they’re judging the merits of virtual analog synthesizers. The biggest and in my opinion most unmerited misconception is to assume that these devices were designed to or must be able to replicate a vintage analog model precisely, down to the most minute detail. In other words, no one in their right mind would complain that an ARP Odyssey is incapable of aping a Minimoog or vice versa. However, some of the more rabid acolytes of analog purism never tire of applying this criterion when rating the Clavia Nord Lead or Access Virus. The industry and its ad campaigns of course did their part to propagate the myth of dead-on simulation, which doesn’t make matters easier for newbies. Your best bet is to think apples and oranges here.

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The Real Analog Vs. Virtual Analog Debate Access Virus (kommt als Scan)

Virtual analog synthesizer: The Access Virus

The bottom line is if you are interested in buying an analog synthesizer, don’t trust anything but your ears. Make your choice based on what floats your boat and possibly won’t sink your budget rather than what someone tells you about the advantages of soldered sound generators over programmed facsimiles or vice versa.

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3 What Analog Sound Synthesis Can and Can’t Do In this chapter, we’ll first try to get a handle on the phenomenon of sound. Then we’ll take a general look at the gadgetry and the principles behind the technical gear that are responsible for generating sound in an analog synthesizer. This should pretty much clarify what analog sound synthesis can and can’t do.

Understanding Sound With most natural sonic events, it’s pretty easy to identify how sound is generated, provided of course you’re in the woods to hear the tree fall. With so-called acoustic instruments, you can literally “see” sound being formed: A cudgel descends on a hollowed-out tree trunk or taut pigskin, a finger plucks a string, air is blown into a reed—identifying cause and effect is child’s play, as anyone with a two-year old, a pot, a spoon and borderline nervous breakdown will attest. With a synthesizer, however, you have to work a little harder to visualize how sound is formed. A bit of basic insight into the physical structure of sounds is certainly helpful, particularly if you at some point want to create your own imitations of sounds. However, before you misappropriate your precocious kid sister’s physics handbook and start getting into terms such as harmonics, amplitude, transients and the difference between sound and noise, you’re probably better off first looking at the components that generate sounds in an analog synthesizer. After all, you might find that it is not particularly well suited for imitating sounds …

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3 What Analog Sound Synthesis Can and Can’t Do

How Is an Analog Sound Generated? Before we take a quick tour of a synthesizer’s components, let’s look at how an analog sound is shaped. An analog synthesizer uses three “signal carrying components,” in other words, components in which a signal is generated and/or processed: ❖ one or several oscillators, each of which generates a waveform, ❖ a filter which lets you filter overtones out of the waveform and thus manipulate the timbre or tonal color, i.e. make the sound of the oscillator waveform “softer” or “darker,” and ❖ an amplifier to control the volume level. Signalweg des analogen Synthesizers

Signal path of an analog synthesizer with oscillator, filter, amplifier and audio output (Nord Modular)

The manner in which the filter and amplifier operate inspired the name of this type of synthesis: These two components take something away from the original oscillator waveform—they subtract elements, which is why the technically correct jargon for this process is “subtractive synthesis.” You can well imagine that the sound produced by the three components is extremely static: Neither the sound nor the timbre are subjected to any type of change during its brief existence.

32

How Is an Analog Sound Generated?

To animate the, to put it mildly, lifeless sound that is generated, synthesizers are equipped with control features that influence certain parameters of signal carrying components. The presumably most significant of these control features are the envelope generators. Envelopes produce time based sequences for the parameters to which they are addressed. For examples, if an envelope controls the amplifier, then the volume of the sound changes in accordance with the envelope’s defined values. If it controls the frequency of the filter, the timbre of the sound changes; if it controls the frequency of the oscillator, the pitch changes. 24envelope.eps

Envelope

Another crucial control module is the LFO, which is short for “Low Frequency Oscillator.” This is essentially a conventional oscillator with the difference that its oscillation frequency is extremely low, well below the audible range of human hearing. Although you can’t hear these ultra-slow oscillations, they come handy as control signals for repetitive or cyclic modulations. For example, if you control the frequency of an oscillator via an LFO, the pitch changes periodically in accordance with the LFO oscillation. This effect, in music argot, is called “vibrato.” If you control an amplifier via an LFO, the volume of the sound varies periodically in accordance with waveform of the LFO. The music world calls this variation in level “tremolo.”

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3 What Analog Sound Synthesis Can and Can’t Do

In addition to the control signals of envelopes and LFOs, there are realtime control signals available; these let you manipulate the instrument’s sound at any time you desire, with immediate effect. The most conspicuous exponents of these gadgets used to generate realtime control signals are the descriptively named wheels, of which one— the modulation wheel—traditionally controls the intensity of the LFO, and the other—the pitch wheel—is a variable pitch controller. The latter’s effect is comparable to the sound of a string being bent on a guitar. The synthesizer’s keyboard gives you a couple of more realtime control options. On the early synthesizer models, the keyboard was designed solely to input pitch information, i.e. select notes, but in time resourceful designers implemented two more functions: ❖ velocity, which is information on your playing dynamics; i.e. how hard you bear down on a key when you strike it, ❖ and aftertouch, which is similar, but refers to the amount of pressure you exert on a key once you have played a note and are holding the key down. Traditionally, velocity is used to control volume levels, another popular application is to manipulate the filter frequency so that louder notes sound brighter than softer notes. Finally, you have two more types of rudimentary control signals which are really nothing more than on/off switches: gates and triggers. In the fairly simple synthesizers that we’re talking about here, these signals are generated exclusively by the keyboard. Think of a trigger as the start gun of an event. When the keyboard “fires” a trigger signal, the race is underway and runs its course even when you release the key. A trigger signal is a single electrical pulse or command.

34

Is an Analog Synthesizer a Gifted Mimic?

The aptly name gate is also a pulse, but like its real-world counterpart, is either “open” or “closed.” If you use your keyboard to control an envelope via a gate signal, then the envelope is started when you press a key and runs through a predefined sequence. It holds or sustains at this predetermined position in the sequence until you release the key. Then the gate closes and the sound begins to decay or fade out. In contrast to a trigger, a gate has a beginning and an end. Well, that’s about it for a brief introduction to the components that an analog synthesizer uses to generate sound. The basic principle is presumably fairly clear to you. Before we take an in-depth look at the individual modules, their parameters and how these affect sounds, we’ll take a break from the purely technical discourse on the inner workings and approach the entire concept a little more philosophically. Bear with me, it won’t take long and it won’t hurt a bit.

Is an Analog Synthesizer a Gifted Mimic? Although we’ve barely scratched the surface in our analysis of an analog sound generator’s architecture, you might consider it highly unlikely that a machine structured as simply as this is actually capable of aping the mindboggling abundance of sounds and noises produced in our environment. Indeed, your skepticism is entirely justified: Every bargain-bin sample player, any 100 $ soundcard—to use cliched comparisons—does a better job of rendering the sound of a grand piano than the most expensive modular analog synthesizer. Ergo, judged on its imitative merits, an analog synthesizer is a colossal failure. This fact certainly contributed to its near extinction during the sampler heydays of the Eighties. What saved it from being a footnote in the history of musical instruments and led to its modern-day revival is the fact that it is an ideal tool for creating truly novel sounds. Seen in this light, the simplicity of the device is actually a boon: you don’t need a degree in physics to make new noises. Equipped with just a few basic facts about the box, you can tweak the odd parameter and come up with stunning results in no time at all.

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3 What Analog Sound Synthesis Can and Can’t Do Juno 1

Simple stuff, easy to suss: The front panel of the Roland Juno-106 turned newbies into sound programmers almost instantly.

Moreover, the architecture of an analog synthesizer makes it easy for you to intuitively and spontaneously manipulate the tonal spectrum of sounds in realtime. Rather than simply play notes and make music in the conventional sense, you can also “play” sounds. This is an option that no other type of synthesizer offers in this form.

The Basic Components of Analog Sound Generation In the following chapters, you’ll come across a bevy of terms that you may have never read or heard before. Due to the nature of early synths—these were electronic machines in the clanking, cumbersome industrial sense of the word—most synthesizer jargon has its origins in physics, electronics and acoustics. Don’t panic! Keep in mind that no matter how intimidating a technical name might sound, it’s usually no more than a very complicated label for a very simple function. The object of this book is certainly not to confuse you or muddle what knowledge you might already have. Quite the opposite, the point is to enlighten you. We’ll look at even the most obvious of these terms as we hack our way through the terminology jungle. If you come across a term

36

The Basic Components of Analog Sound Generation

that you are unfamiliar with or its meaning temporarily escapes you, check out the “Pocket Compendium of Analog Sound Synthesis” from page 117 onwards. Anytime you’re uncertain of what it is that I’m rambling on about, simply take a peek at this quick-reference section.

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4 Oscillators Oscillators are the synthesizer’s engine room, they provide the power— waveforms—which fuels the sound-shaping section, i.e. gives it something to work with. In many synthesizers, you’ll find that the oscillator modules are labeled with the abbreviation “VCO.” VCO is short for “Voltage Controlled Oscillator.” What this means is that pitch and other parameters are controlled in the “traditional” analog manner—via electrical charges. When the digital revolution made its mark on synthesizers, the term “DCO” became frequently associated with synth oscillators. The abbreviation stands for “Digital Controlled Oscillator,” which means just that, i.e. a digital component rather than a voltage generator controls the oscillators. However, even in a DCO, the actual waveforms are generated in the usual analog manner.

Waveforms If you give the most common waveforms of an analog synthesizer the aural once-over, you’ll be inclined to agree that the terms “raw material” hit the nail on the head. Harsh, crude, electronic or even down-right ugly are some of the adjectives that come to mind when asked to describe the racket issuing forth from the speakers. You might be wondering what kind of twisted mind had the brilliant idea of using these grim waveforms rather than something less grating. You can be sure that the engineers who pioneered sound synthesis would have loved to include more appealing waveforms had they had the means. The truth is that early synth designers had no choice: precisely these waveforms were what the then roughhewn analog electronic circuitry was capable of producing.

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4 Oscillators

In this chapter, we’ll take a look at the standard waveforms and describe their shapes as well as tonal properties. We’ll also compare them with similar sounds that you might be familiar with and probe their suitability for programming sounds. Keep in mind that especially for this last point— programming sounds—there are no hard and fast rules, just a few guidelines that might make life a bit easier for you. Initially, all of this leeway may seem intimidating, but bear with me. The good news is that it spells creative freedom galore: You can take any waveform and manipulate it so that you come up with something totally different. Sawtooth Wave

The sawtooth wave, sometimes shortened to “saw,” features more overtones than any other analog synthesizer waveform—all of the overtones to be precise. This property makes it the most productive waveform for analog synthesis. As you recall, this type of synthesis is based on “subtracting” elements from the original signal. If you have a signal chock full of harmonics, you can “milk” it for all its worth. The sawtooth wave typically has a hard sound. It is often used to program pads, strings and brass horns; this waveform is always a prime candidate when ever you’re going for a “fat” sound. CD track 02: Sequence with sawtooth waveform

40

Waveforms

Square Wave

The square, also called “rectangle,” wave was like the other waves named for its natural shape. In it, the duration of a pulse is equal to the pause or rest between pulses, which means that measured over the course of the entire wave, the ratio of the two is 1:1. The square wave is actually a special form of a pulse wave. Characteristically, because it contains odd harmonics only, a square wave sounds hollow, “electronic” and is reminiscent of the sound of a clarinet. A square wave is your best bet when you want to program “scooped” sounds or imitate cheap, tinny instruments. CD track 03: Sequence with square waveform

Pulse Wave The pulse wave is also a rectangle or square waveform, the difference being that you can vary the relationship between the pulse and rest infinitely. Pulswelle mit unterschiedl. Pulsbreiten

Pulse wave with different pulse widths.

As the width of the pulse decreases, the sound tends to sound less like a clarinet and more like a bassoon and oboe. In other words, it has a more “nasal” sound than a square wave. Generating thin, nasal sounds are what the pulse wave does best.

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4 Oscillators

In most synthesizers, you can change or modulate the pulse width “externally,” for example via an LFO. This process is imaginatively called “pulse width modulation” or PWM. The result is anything from a slight shimmering effect to heavy-duty chorus, which is best described as the sonic equivalent of growing old: everything gets softer, wider and cozier. CD track 04: Sequence with pulse waveform, the pulsewidth changes during the course of the sequence.

Triangle Wave Pulswelle mit unterschiedl. Pulsbreite

The triangle wave sounds like a highly filtered square wave. Its typical sound is soft, reminiscent of a flute. It is predestined for making flute-type noises when you use it as the raw material for programming sounds. CD track 05: Sequence with triangle waveform

Sine Wave

A sine wave is the softest sounding of all common synthesizer waveforms. It consists solely of the fundamental tone and contains no overtones, just like a tuning fork, which is exactly what it sounds like. Every timbre or tonal color is the sum of sine tones with different frequencies and volume levels, which is why you could call the sine wave the “heart” of all sounds. Good-to-know stuff that is sure to be a conversation-stopper at your next dinner party: Overtones or harmonics are sine vibrations.

42

Waveforms

Unless you enjoy wasting your time, don’t try to filter a sine wave: A filter is designed to remove overtones. Alas, a sine wave is devoid of these, so you can be sure that absolutely nothing will happen. You might be thinking something along the lines of “If subtractive synthesis is what all of this is about, what good is a wave that I can’t subtract anything from?” Actually, the sine wave does come in handy when you want to generate cardiac arrest inducing subbasses typical of techno and drum ’n’bass tracks. It is also good for coming up with organ sounds as well as Ufo, stun-gun and laser effects. CD track 06: a. Sequence with sine waveform, b. sine subbass, c. sine laser

Noise

Noise is a random signal comprised of an equal portion of all frequencies at the same volume, which as you might have already guessed, does not have a specific pitch. For the closest approximation of its sound, think Niagara Falls heard from a distance the day after one too many Margueritas. In most synthesizers, noise is not generated by the normal oscillators, but by a special descriptively named “noise generator.” In most cases this racket maker produces two types of noise, white noise and pink noise. Whereas white noise—like white light—comprises the average of an equal portion of all frequencies, pink noise (which is usually derived from white noise) emphasizes the lower frequencies so it sounds a bit darker. Both types of noise are suitable for creating sound effects such as wind, pounding surf and thunder. They are also nifty condiments when you’re programming drum sounds or trying to emulate the breathy attack of a woodwind or brass instrument. CD track 07: a. Seamless crossfades between white and pink noise b. Analog drum kit—all drums based on noise

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4 Oscillators

Oscillator Settings The most important and often only parameters that you can manipulate on an oscillator module are the waveform that you want the oscillator to generate and its frequency, in other words, pitch. Generally, the module will feature some type of control element that lets you select the desired pitch in half-tone increments and another for finetuning between two half-tone steps. Often vintage analog synthesizers feature an octave or footage selector for each oscillator. The term “footage” has its origins in the nomenclature of the pipe or reed organ where size does matter—the longer a pipe, the lower the note. A 16' pipe is thus twice as tall and sounds an octave lower than the 8'. If the oscillator is capable of generating a pulse wave, then it usually features an additional control that lets you manipulate the pulse width, which of course is disabled for all other waveforms.

Axel Hartmann

Abbildung Oszillator-Modul

A typical oscillator module with a waveform selector, coarse- and fine-tuning knobs as well as a variable pulse width control.

Combining Oscillators In terms of tone, a solitary oscillator is fairly boring, it needs some company to liven up the party. This is why you can combine several oscillators. You can create a much fatter, livelier sound by combining two oscillators and slightly detuning them. Twelve-string guitars, which have a bigger sound than their six-string cousins, are based on the same principle.

44

Waveforms

By the way, if you lower the pitch of one oscillator by three cents (a cent is hundredth of a half-tone step) and increase the pitch of the other by the same value, you will actually perceive the signal in the original pitch. For some reason, the human ear automatically “tunes” the two signals so that you will hear the sound as being in tune with other properly tuned sounds. It takes a certain degree of detuning before the sound is appreciably out of tune, which can be a desirable effect if you are trying to come up with some off-beat or “outside” sounds. CD track 08: Crossfade: One oscillator alone 

two oscillators 

increasingly detuned

You can also tune two or more oscillators in musical intervals, which considerably fattens up a sound. Popular tunings include intervals of fifths or octaves. For example, if you have come up with an anemic bass sound, add some muscle by detuning an oscillator by an octave up or down. Synth designers were quick to note that this effect pumps up puny sounds, so many synthesizers feature a suboscillator. for this purpose. Its signal is usually derived from another oscillator. The frequency is simply halved and the lower octave is added to the original signal. CD track 09: a. One oscillator alone, b. two oscillators tuned a fifth apart, c. two oscillators an octave apart

Waveforms Rather than simply overlapping waveforms, many synthesizers give you one or even several options for modulating one oscillator’s waveform via another oscillator. As you can well imagine, this type of feature substantially increases the range of sounds you have available. In an analog synthesizer, this is the only way of creating spectra beyond the relatively limited selection of waveforms that we discussed earlier. In the following section, we’ll take a closer look at the most common oscillator modulation options:

45

4 Oscillators

Oscillator Synchronization (Sync) In this context, synchronization means that as soon as the waveform of the modulating oscillator has run through a zero cycle, it resets the waveform of the modulated oscillator to start it anew. Usually, you’ll find a button or function labeled “Sync” that allows you to activate this option. What happens here is that the waveform of the modulated oscillator is interrupted at some point during its oscillation. If you tune the two oscillators to different pitches, you can achieve an extremely penetrating sound with anything from a slight metallic flavor to uranium depleted, armor piercing, metallica. CD track 10: Sequence with synchronized oscillators, the slave oscillator is detuned. Abbildung Sync

Slave Osc Master Osc Reset Sync Wave Synchronization: The waveform of Oscillator B is reset to zero by Oscillator A.

Ring Modulation Ring modulation is generated by a circuit that routes out the sum and difference of two incoming signals. If you input 200 and 800 Hz (a twooctave interval) to the ring modulator, it will output 600 and 1,000 Hz. Originally, designers equipped synths with ring modulators to be able to emulate gongs, bells or industrial sounds such as toppling metal plates; the standard waveforms of these instruments were totally unsuitable for this type of application. Today’s samplers of course do a much better job of getting these sounds right. Nevertheless, the ring modulator still has its merits—it lets you come up with true weirdness, effects bizarre enough to defy categorization. CD track 11: Diverse examples of ring modulation

46

Waveforms

Amplitude Modulation In an amplitude modulation (AM), the output signal of one oscillator modulates the amplitude of another oscillator’s waveform. This sounds like a tremolo effect, albeit one where the frequency of the tremolo is within the audible range. Like in all modulations with an audible oscillation, here too a new spectrum is generated. The product of an amplitude modulation is not for the faint-hearted; you usually get a distorted, razor-sharp sonance, the aural equivalent of running your finger tips down a cheese grater. CD track 12: Amplitude modulation—the modulator is transposed in semitone steps into the range of audible frequencies.

Frequency Modulation In a frequency modulation (FM), the output signal of one oscillator modulates the frequency of another oscillator. This effect generates extremely complex spectra that defy description, but nevertheless deliver anything from interesting to truly freaky effects. Since 1985, with the introduction of the Yamaha DX synthesizers, FM has become a distinctive and very popular form of sound generation. Today, less sophisticated forms of FM ship with practically all synthesizers. CD track 32: Frequency modulation: a. Ratio 1:1, the modulator is slowly turned up, b. constant level, the modulator frequency is increased in whole-number intervals (1:1, 1:2, 1:3…)

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5 Filters Of all the components in an analog synthesizer, filters are the closest to what you could call the “soul” of the beast. When an analog synth wins enough of a following that it is no longer perceived as a box full of haphazardly wired components and instead is referred to in hushed tones as “legendary,” you can bet that it was the filter circuit that won the hearts and minds of its acolytes. For example, to this day praise is lavished on the Minimoog’s eternally hip cascade filter. Often the filter stands the test of time while the actual synthesizer that was originally its home is relegated to oblivion. Anyone who has perused the odd keyboards magazine has come across a reference to the notable Oberheim SEM filter, whereas the recognition factor for the synth it was initially installed in is akin to that of such ground-breaking contrivances as Cup-O’-Pizza. The filter’s prominence is a product of its function: To belabor the obvious, it filters overtones out of an oscillator’s signal and is thus capable of generating thousands of different timbres from a single waveform. And although in theory an analog filter is extremely easy to build, in practice the performance of filters with identical specs is wildly divergent. Some claim that constructing filters is a higher art, and I’m inclined to agree. As you try out different models, you will presumably come to the same conclusion: The skills of the people who designed the filters lastly make the difference between a “good” or “bad” sounding analog synthesizer. In many synthesizers, the filter module is labeled with the abbreviation “VCF.” VCF is short for “Voltage Controlled Filter,” which tells us that this type of filter is “jolted” into action. As progress continued its inexorable march, more and more synthesizers began to feature “DCF” filters, which is short for “Digital Controlled Filter.” It’s all in the name: Here a digital component rather than a voltage source controls the cutoff frequency. Purists take note: The actual filter circuit in a DCF is analog.

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5 Filters

Filter Settings: Cutoff and Resonance Although filters are your most important sound-sculpting tools, the availability of control features that you can fiddle with is fairly limited. There are only two knobs, one for the filter’s frequency, called “Cutoff Frequency” or simply “Cutoff” and one for resonance, also called “Q.” Cutoff is nothing more than a threshold, i.e. the frequency at which the filter begins modifying a sound. Depending on filter mode, the frequencies above, below or in the immediate neighborhood of a given cutoff frequency are affected. The Cutoff knob lets you preset this frequency; it can also be modulated via envelopes, LFOs or other control signals. Varying the cutoff frequency continuously over a wider range—manually by rotating the Cutoff knob of automatically via a modulator—is called a “filter sweep.” CD track 14: Filter sweep envelope with notes played at staggered intervals

The Resonance knob lets you accentuate the frequency range bordering the cutoff frequency. Although this doesn’t sound like a particularly spectacular effect, resonance is precisely the ingredient that spices up a filter’s sound. Without resonance, a filter would sound about as impressive as standard bass and treble controls on your fire-sale car radio, which is to say not very impressive at all. Wah-wah and similar effects would be unworkable without the resonance parameter, our lives would be tragically devoid of funkability, and all popular music would sound precisely like (insert the name of the most soulless, only-in-it-for-the-money band or artist particularly abhorrent to you here), leading to the end of civilization as we know it. CD track 15: Sequencer bass where the resonance is slowly turned up to the point of self-oscillation.

Resonance can also be used to conjure up some sonic magic that for the longest time was solely the domain of analog filters. Even today, not all digital filters are capable of achieving what is in synth jargon called “self-oscillation,” which has nothing whatsoever to do with autoeroticism. If, on a fil-

50

What Types of Filters Are There?

ter capable of self-oscillation, you turn the resonance up to the hilt, many filters will produce a sine tone with a frequency equivalent to that of the cutoff frequency, which comes in particularly handy when you are programming electronic drum sounds.

Axel Hartmann

Abbildung Filter-Modul

A typical filter module with filter mode selectors and Cutoff and Resonance knobs.

What Types of Filters Are There? To avoid any confusion while we’re discussing filters, bear in mind that the usual specifications such as “24-dB” or “12-dB filter” don’t actually describe the type of filter that you are dealing with. These specs refer to something called the slope of a filter. We’ll take a closer look at this attribute a little further down the road. For now though, when we’re talking about filter types or modes, we basically mean the logic behind the filter: Which frequencies are filtered out of the oscillator signal? Although strictly speaking, you could say that there are really only two filter types, we’ll be generous and claim that there are generally four filter types in synthesizers:

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5 Filters

Low Pass The most popular type of filter is the “Low Pass Filter,” rather unsurprisingly abbreviated “LPF”. A low pass filter allows only those frequencies through that lie below its cutoff frequency. The low pass is kind of the fabric softener among filters, it turns a rough, scratchy sawtooth into a soft, fuzzy horn sound. Reasonably, when you take higher frequencies out of a signal, the percentage of lower frequencies in the sound increases, which in subjective terms, produces a warmer, fatter sound. CD track 16: Low pass sweep from top to bottom, high resonance Abbildung Tiefpaß

Level Resonance

Cutoff

Frequency

A low pass filter allows only frequencies below its cutoff to pass.

High Pass You may have already guessed it, but for the record, a “High Pass Filter,” abbreviated “HPF,” is the antithesis of a low pass. It allows only those frequencies that lie above its cutoff frequency to pass. A high pass is generally used to come up with thin, tinny sounds or something shrill enough to stun a rhino at a hundred paces. CD track 17: High pass sweep

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What Types of Filters Are There? Abbildung Hochpaß

Level Cutoff

Frequency

A high pass filter allows only frequencies above its cutoff frequency to pass.

Band Pass A “Band Pass” filter, “BPF” if you’re in a hurry, consists of a low and a high pass filter in a serial circuit. Logically, the filter circuit allows only those frequencies to pass that its two filters let through. A band pass lets you do isolate a given filter band so that you can hear just it. The frequency that lies dead-center of this frequency band has in tech-talk, the uninspired but accurate name “center frequency.” If the curve of the band pass is extremely steep—which is why it is often called a high “quality” filter—then you end up with a de facto formant filter. Formant filters are excellent tools for mimicking the natural resonance of acoustic instruments (violin, piano) and the human voice box. CD track 18: Band pass sweep

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5 Filters Abbildung Bandpaß

Level

Cutoff

Frequency

A band pass allows only frequencies bordering its center frequency to pass.

Band Reject A “Band Reject” filter, also called a “Notch Filter,” is the inverse of the band pass. This filter features a low and a high pass filter in a parallel circuit. It lets you “gut” a sound by cutting a particular band out of the signal that you don’t like. A band stop with an extremely narrow bandwidth and a steep slope is called a “Notch Filter.” This special type of band stop filter lets you remove unwanted frequencies with surgical precision (well, sort of). CD track 19: Band reject sweep Abbildung Bandsperre

Level Cutoff

Frequency

A band stop eliminates a relatively narrow frequency band from the signal.

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Combining Filters

Combining Filters Some synthesizers allow you to combine several filters in different configurations. As far as older models go, this feature is found in diverse modular systems as well as a couple of the “If-you-mortgage-the-house-tobuy-another-toy,-I’m -moving-in-with-Mother” variety of high-end instruments. In “virtual analog” systems, this feature is generally par for the course—yet another point in favor of the upstart generation. Aside from the fact that it’s more fun when you have more stuff to play with, combining filters gives you additional sound-shaping flexibility. If you set up two specimens of the same filter type in series, the filtering effect is cumulative. For example, if you marry a 12-dB and a 6-dB low pass, the offspring will be an 18-dB filter, which is great for programming TB-303-type sounds. Couple a high pass and a low pass in parallel, then you will end up with the kind of band stop we just talked about, connect them in series you get a band pass. If a synthesizer enables you to combine low and high pass filters freely, you get a band pass and band stop for next to nothing. Combining filters definitely gives you plenty of leeway for tonal alchemy. When you put on your lab coat and break out the beakers, your best bet is to start with signals that have loads of overtones, for example sawtooth or noise, because this high-calorie bait sets off a feeding frenzy in filters.

Slope We’ve referred to the “slope” of a filter several times, so an explanation is definitely in order. Slope refers to how radically the filter cutoff kicks in. The steeper the slope, the greater the filtering power. In audio jargon, slope is indicated as a dB/octave value. In this context, “octave” indicates that the frequency is doubled. For example, if you set a value of 12 dB/Oct for your 12-dB filter at a cutoff frequency of 1,000 Hz, then the frequencies at 2,000 Hz are cut by 12 dB, at 4,000 Hz by 24 dB and so forth.

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5 Filters Filterkurven m. versch. Flankensteilheit

Cutoff

24 18 12 dB/Octave

If you look at different synthesizer filters you’ll find that they have slopes of 12 dB, 24 dB, maybe occasionally 6, 18 or 48 dB, but evidently filters with 8 or 26 dB were not big hits with synth designers. The reason for this is rooted in how the hardware of analog filters is set up: The most rudimentary analog filter consists of a coupled circuit equipped with a resistor and a capacitor. This circuit forms an RC component. This type of RC component damps the signal by 6 dB/octave. Filters with steeper slopes are basically nothing more exciting than a combination of several RC components. In tech-talk, this is called cascading; it creates filters with slopes of 12 or 24 dB. This profound insight also helps unveil more mysteries that you’ll occasionally encounter when you’re messing about with filters. Every RC component is a filtering stage called a pole. A filter featuring four of these stages and thus a slope of 24 dB/octave is called a “4-pole filter.” Now that you know a little bit about the terminology used in conjunction with filters, you should find it easier to figure out what your favorite keyboard mag, synth manual or that surly guy at your local retailer are blathering about. A common assumption is that the slope of a filter says something about its quality, you know, the “bigger is better” syndrome. Don’t be fooled, a 24 dB filter is not necessarily superior to a 12 dB filter. In terms of music—the tonal quality of a synth—this is notion is hokey. The fact is that filters with different slopes are suitable for different applications. Here are a few general pointers on the most common of all filter types, the low pass filter: ❖ Filters with slopes that aren’t quite as steep are great when you want to modify a sound slightly but not bend it all out of shape. This is exactly why many samplers ship with more “natural” sounding filters with a slope of just 12 dB.

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The “Sound” of a Filter

❖ Filters with a steeper slope of 24 dB and higher allow you to drastically alter the timbre of sounds. You’ll find that these sound more “artificial” and electronic. You could say that these filters actually “create” new sounds rather than shape an existing sound. If you’re into heavier, punchier sounds, this type will be your filter of choice. CD track 20: a. Poly-synth phrase without filter, b. with 12-dB filter, percussive envelope, c. with 24-dB filter, percussive envelope

The “Sound” of a Filter Again, the slope of a synthesizer’s filter doesn’t determine its quality, for that matter, neither does anything else that you could express in terms of technical data. What does make the difference between a killer filter and a real dog is oddly enough a quality that it doesn’t actually possess, its “sound.” Filters don’t generate sound, but “synthesists” have used the term for many years, so who are we to argue the point? So what exactly makes a filter sound like you want to take it home and introduce it to Mom? What is it lacking that makes it sound like you wouldn’t wish it on your worst enemy? Well, in my experience, the attributes—good or bad—generally ascribed to a filter are almost always exactly the same as those attributed to the synthesizer that it calls home. The sound of the much lauded 24-dB filter in the Moog synthesizer is often described as “fat,” and indeed, producing fat sounds is one of the things that this legendary synth does best. The sound of the 12-dB filter of the Oberheim OB-8 is widely recognized as so “soft” that it will make you think about fuzzy cashmere sweaters and then other things you probably shouldn’t be thinking about. Although I’d like to be able to answer questions about what it is that makes a filter sound “good” or “bad,” to be honest, there is no answer that comes even a remotely close to being objective. For example, the 18-dB filter of the Roland Bassline TB-303 is not—by anyone who hasn’t taken leave of his senses—considered a good filter, but it is nevertheless responsible for plenty of legendary and “good” sounds. The sound or tonal characteristics of a filter have less to do with technical data and more with the unique inconsistencies, distortion and coloration that it adds to a sound.

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6 Amplifiers The amplifier is the final link in the chain of signal carrying components in an analog synthesizer. Its job is not exactly what you might call glamorous—it determines the volume of the signal routed from the oscillator via the filter. This is why it has just one control feature, usually labelled “Level” or “Volume.” On many synthesizers, the name of the amplifier module is abbreviated “VCA,” which stands for “Voltage Controlled Amplifier.” This pretty much sums it up—a VCA is an amplifier that gets zapped with different voltages to make it do what it should, which makes it hard to write anything more interesting about the VCA. DCA module with an envelope in the control and an oscillator in the signal circuit (Nord Modular).

abbildung dca-modul

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6 Amplifiers

After the dawn of the digital age, many synthesizers began sporting the label “DCA” for their amplifiers. This abbreviation stands for “Digital Controlled Amplifier,” which means that digital component rather than a voltage generating source tells the amplifier what to do. The actual amplification circuit of a DCA is however analog.

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7 Envelopes Any sound generated by the three components that we just had a closer look at is extremely static: The oscillator generates a waveform, the timbre of which can be altered to some extent in the filter, and the amplifier pumps the signal up to a level that allows the world at large to hear it. Although in the name of art, Brian Eno has every right to play a sine tone for 25 minutes straight, the rest of us also have the artistic freedom to manipulate the sound as we see fit. For example, if you want a sound to fade in gradually and from a given point fade back out, you would have to turn the Volume knob of the amplifier module up and back down again. If at the same time, you want to change the timbre of the sound, you would have to twiddle the Cutoff and Resonance knobs of the filter. At this point, even if you had three hands, you would be pretty busy. You don’t have to take this scenario further to surmise that tweaking knobs manually just won’t cut it. The good news is that you don’t have to because synthesizers feature handy little tools that do what you want them to automatically—“Envelope Generators,” “EG” for short.

What Does an Envelope Do? Its name hints at its function, at least when we’re talking about amplitude envelopes. As you might have guessed, this type of envelope is responsible for controlling the volume curve of a sound. The principle here: Only the part of the sound that you “stuff” into an envelope ends up being sent to its destination, your ears.

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7 Envelopes

What Type of Envelopes Can I Play With? ADSR vs. Multistage Models The most common type of envelope in analog synthesizers is the ADSR envelope. Its name is yet more alphabet soup representing the ingredients that you can flavor to taste, the parameters “Attack,” “Decay,” “Sustain” and “Release.”

Decay Time Attack Time

Sustain Level Release Time

Key down

Key up

ADSR envelope

Possibly the easiest way to get a handle on what these terms mean is to take a look at the diagram of a volume envelope depicted below: The Attack time determines the amount of time it takes for a curve to ascend from zero to the maximum level when you trigger it, for example by pressing a key on the keyboard. The Decay time determines how long it takes for the sound to drop off from its peak level to the Sustain level. The sound remains at the Sustain level until you release the key. Once you release the key, the curve drops back down to zero. The duration of this final stage is determined by the Release time. This envelope model has the advantage that it is very easy to understand. The only drawback is that three parameters are used to manipulate time, the other to control level, so you’re dealing with apples and oranges. Although you’ll soon get the hang of it, I feel compelled to mention this

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What Type of Envelopes Can I Play With?

distinction because it tripped me up once or twice when I first started exploring the wild & wacky world of synthesizers. After messing around with the ADSR envelope for a while, you’ll find it so easy to handle that you may wonder what the fuss was about. The incredible lightness of being an ADSR envelope has its price—this is not the most flexible sound-shaping tool you’ll ever come across. For example, say you want do something not all that exotic such as trigger a sound at a volume other than zero, and instead you’d like it to start at half its peak volume. You’ve probably anticipated what I’m leading up to, and you’re right: It simply can’t be done with an ADSR envelope. The peak level—i.e. the volume the sound attains once the Attack phase has run its course—is also predetermined. Moreover, once the sound’s Release phase is over, you can’t have the level hang about at say 70 % of peak level because the inflexible architecture of the envelope will always send the level careening down hill to zero. Oddly enough, this is not a huge disadvantage when you’re dealing with volume envelopes. However, when you sic an envelope on the filter or pitch, you will find this lack of flexibility annoying. Yes, an envelope-to-filter/pitch option is available, and we’ll look at it soon, but before we get ahead of ourselves, back to the types of envelopes. Abbildung 4-Segment-Hüllkurve

L1

L4

100 T4

T1 L0 0

L3

T2

Key down

T3 L2

Key up

The 4-stage envelope gives you four segments for which you can determine both the duration and level.

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7 Envelopes

With the Yamaha DX7, which of course is a digital rather than an analog synthesizer, a new type of envelope was introduced to synthesis: the Multistage envelope. To make this type of envelope a bit easier to understand, we’ll first look at one featuring four stages so that the differences to an ADSR model become eminently clear. In a 4-stage envelope, you have four phases that you can manipulate, each in terms of time and level. The type of envelope depicted in the illustration below is thus possible—what you certainly can’t say for an ADSR envelope. In analog synthesizers—which coincidentally happens to be the topic of this book—you’ll find almost exclusively ADSR envelopes. An exception is the virtual analog Clavia Nord Modular, which features multistage envelopes from Version 2.0. Just goes to show that virtual analog synths can do a great deal more than just mimic vintage analog gear when the designers know how and are willing to exploit the advantages of digital technology.

Where Can I Use Envelopes? As we touched on earlier, the application options for envelopes are not limited to manipulating the amplitude of a sound to shape its volume curve. As a rule, you can use an envelope to control virtually every parameter and come up with good results. However, the effort you have to put forth in finding the right spot to patch the envelope into the signal chain is formidable; when you’re dealing with truly analog synth, we’re talking actual work here. This is one of the reasons why elephantine modular systems, where money wasn’t much of an object anyway, were substantially more versatile than their cheaper hard-wired cousins. When the digital revolution caught on, the problem was solved: Processors took over the chore of assigning modulation sources to possible modulation destinations. Let’s take a closer look at the most common applications for envelopes.

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Where Can I Use Envelopes?

Amplitude Envelope In most synthesizers, an envelope is reserved for controlling volume. Like that one guy who always sits on the same stool at the end of the bar, it will never, ever be found anywhere else. To mix metaphors, this envelope determines if a sound comes on like firecracker or fades in and out as smoothly as a Glen Livet. CD track 21: Amplitude envelopes: a. organ, b. piano, c. backwards, d. brass

Filter Envelope A filter envelope has a much greater influence on a sound than an amplitude envelope. Why synth designers are often more than miserly when it comes to equipping it with parameters is one of life’s profound mysteries, and undoubtedly compelling grounds for the big thumbs down when synth maker Judgement Day rolls around. Another pet peeve of mine is that you’ll find more synthesizer models than you should where the VCA and VCF have to share the same envelope. This is bad because it limits your sound-shaping options even more. When you’re emulating acoustic instruments for example, the filter envelope is responsible for making the sound grow darker as it fades out—just picture the typical response of a piano or guitar and you’ll know what I mean. Another common trick is to slightly increase attack time to simulate the time it takes for a brass or woodwind instrument to “warm up” when a player blows into it. In terms of shaping sounds creatively, the filter envelope is your most important tool. It literally has life-and-death power over a sound because this envelope determines its timbre. This is ultimately the criterion that defines the essence of a sound. For the record, the type of filter envelope that we’re talking about here generally modulates just one of the two parameters of an analog filter, its frequency. You’ll rarely find a synth equipped with a resonance envelope, or more accurately, the option of assigning an envelope to this parameter.

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7 Envelopes

This is a shame, because when you’re in the mood for creating the sound track to that sci-fi flick your film school buddy is making or generally whipping up wacky sounds, you would certainly find that this feature comes in handy. Pitch Envelope A pitch envelope is turned loose on the frequency of an oscillator to change the pitch of a sound automatically. People who enjoy imitating instruments of a classical orchestra with their analog synths like to use the pitch envelope to wreak a little havoc on the oscillator to simulate the brief moment it takes for trumpets, trombones and other brass instruments to “warm up” to proper pitch. This undeniably esoteric application does however demonstrate one of the drawbacks of the ADSR envelope: To ensure that the ultimate pitch of the sound, which in this case is determined by the Sustain level, you have to painstakingly readjust the oscillator frequency, which indeed is a pain. When you crank up the intensity of the envelope and set suitable Decay times, you can use a pitch envelope to come up with the once so popular “pee-you” sounds reminiscent of the great Syndrum era as well as diverse “zip” and “zap” sounding effects. For you drum’n’bass freaks, those familiar subbass sounds that in the post-attack phase drift off towards the infrasonic realm wouldn’t be possible without a pitch envelope. There’s really no cookbook featuring recipes for these and many more effects that you can conjure up with using the pitch envelope. Your best bet is to start twiddling and stop when you’ve found something that sounds cool to you. CD track 22: Pitch envelope: a. percussive, b. trumpet, c. synth, d. synth brass

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Are there “Good” and “Bad” Envelopes?

Modulating via Envelopes Here we’re starting to drift into the deep end of the pool. Envelopes—by definition modulators—that can control the functions of other modulators are not exactly standard equipment on basic synthesizers. Although this feature is rarely found on your run-of-the-mill synth, it’s definitely worth taking a closer look at. For example, you can come up with pretty nifty results when you are able to manipulate the rate of an LFO via envelope: a fair approximation of a Leslie when it fires up after you release the breaker. You can well imagine the kind of bizarre stuff you could come up with if you take this effect to the nth degree. If you use an envelope with negative polarity as the source and its own time parameter as the destination, the top of the envelope curve is compressed and the bottom flattened out. This creates an exponential curve with substantially more “snap”—good stuff for percussive sounds.

Are there “Good” and “Bad” Envelopes? What was a matter taste in judging filters can here be answered with an unequivocal “Yes.” A “good” envelope is one that does what it should the way that it should. A “bad” envelope is one that is, in synth jargon, simply too “slow.” “Too slow” means that when you set an Attack time of zero, the sound isn’t triggered immediately—instead of the desired “wham” you at best hear “ham.” Yep, this is a real porker. Another phenomenon: The release of percussive sounds is crappy instead of snappy. In this case, the synth is of no use for percussive sounds such as bass lines or arpeggios— which unless you’re solely into making meditative loops where the sounds sustain for as long it takes to experience Nirvana—somewhat limits the application range of your box. Curiously, this “feature” is never mentioned in the bright, shiny product flyers, so be sure to test drive the machine before you buy or talk to your local “guru” to find out if the envelopes are fast enough for having fun.

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8 LFOS LFO is short for “Low Frequency Oscillator,” which is nothing more than your average oscillator. It generates a usually variable waveform and gives you the option of determining the frequency for this waveform. In contrast to an audio oscillator, an LFO does not generate an audible signal—its frequency is so low that the human ear is unable to hear it. The output signal of the LFO is nevertheless a key component in shaping sounds in a synthesizer—you can’t hear it, but it does a bang-up job as a modulation signal. This is presumably why some manufacturers in their infinite wisdom call an LFO a “Modulation Generator,” which all flippancy aside, is a substantially more descriptive name. In contrast to an envelope, which as you now know runs its course from start to end and has to be retriggered to start it anew, the modulation signal generated by an LFO constantly repeats itself, which after all, is not to much to ask of a single waveform. One of these repetitions is called a “cycle.”

LFO Settings Again, technically speaking, an LFO is a normal oscillator, so you’ll find the same options here as for other oscillators: ❖ You can select the waveform which is also called “waveshape” (these two terms are interchangeable). It determines the shape of the modulation signal, for example if it causes the modulated parameter to steadily move up and down (which is the case with a sine wave) or constantly jump back and forth between two settings of this parameter (which is the case with a square wave).

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8 LFOS

❖ You can determine the frequency, which in turn determines the rate at which the LFO waveform modulates the parameter that it is addressing. This is why the knob designed to control the LFO frequency is on most synthesizers labeled “LFO Rate” or “LFO Speed.” Although rare in the synth world, this is nice because the name actually refers to what the control feature does rather than its origin or technical pedigree.

What Do the Different LFO waveforms Do? Like different audio oscillator waveforms produce different sounds, different LFO waveforms produce different modulation signals and consequently different modulation curves. All waveforms have one thing in common—they take the modulated parameter on a kind of “roller-coaster ride,” whereby the peaks and valleys are determined by the shape of a given wave. Here’s a brief run-down on the most common LFO waveforms and my possibly hopeless analogies of what the modulation curve of each cycle resembles: ❖ The “Sine” wave generates a soft, steady modulation curve. Its humps are comparable to gently rolling hills. ❖ The “Triangle,” or “Tri” for short, wave also produces a soft modulation curve, although the peaks and valleys are pointy—think modern art or a series of witches’ hats—so that there is, to return to the mountain metaphor, a distinctly audible ascent and descent. ❖ The ascending “Sawtooth” also called “Saw up,” generates a modulation curve that ascends slowly, and once it peaks, drops off abruptly, kind of like taking a leisurely cable car ride up a mountain and jumping off a sheer cliff to get back down. This waveform is great for creating repetitive backwards effects. ❖ The descending “Sawtooth,” also called “Saw down,” like Superman, who is able to leap tall buildings in a single bound, it jumps to the peak and gently slides back down the other side. When you use this waveform for a filter or amplifier, the effect is very similar to a repetitive decaying note.

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What Do the Different LFO waveforms Do?

❖ The “Square” wave gives you a modulation with abrupt changes in parameter values. To stick with the mountaineering analogy, the signal jumps to the peak, wanders along a highland plateau for a while, jumps off the sheer cliff at the far end and meanders through the valley floor etc. When you use this waveform to manipulate pitch, you’ll get a trill between two pitches. ❖ The “Random” waveform produces a—who would have guessed—haphazard modulation. The waveform looks just like a mountain range as Mother Nature made it, except with steps hewn into it by some giant with a great deal of time of his hands. CD track 23: LFO modulations—simultaneously influencing the oscillator, cutoff and pan—with varying rate: a. sine, b. triangle, c. saw up, d. saw down, e. square, f. random

So much for my somewhat abstract descriptions of the effects of different LFO waveforms. We’ll get to the section on LFO effects a little further down the line, where we’ll look at how to use these to achieve specific effects. But beforehand, I’d like to familiarize you with some of the stuff that you’ll run across when you’re working with LFOs. Abbildung LFO-Wellenformen

Sine

Triangle

Saw up

Saw down

Square

Random

The most common LFO waveforms are sine, triangle, saw up, saw down and random waveforms. By the way, few synthesizers feature random waveforms. Usually, you’ll have to DIY them via a combination of the sample & hold module and noise.

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Controlling the LFO Rate Normally the LFO rate is set to a fixed value somewhere in the range of 10 seconds per cycle (0.1 Hz) to 30 cycles per second (30 Hz). However, a fixed value will produce evenly shaped modulations, which you may find boring after a while. To spice things up a bit, you can modulate the LFO rate, either by another LFO or an envelope. As discussed earlier, wiley programmers like to use an envelope to modulate the LFO rate and thus simulate activation or release of the breaker of a Leslie rotary cabinet. But this isn’t your only option. In other words, if a synthesizer gives you the opportunity to modulate rate of an LFO, you have a vast range of possibilities to literally put some “action” into your sounds. Synchronizing an LFO to a Clock Signal Here’s another LFO control option that comes in really handy: synchronizing the LFO rate and phase to the beat of a song via a clock signal. The most obvious application of this feature is to lock the LFO rate and thus the modulation into sync with a sequencer, and indeed, this is a fine option to have. Things however get really interesting when the clock signal does not generate “straight” eighths or sixteenths, but any other funky time value that you care to come with. Then you can set an LFO modulation against the predominant beat of the music and generate grooves that would otherwise be difficult if not impossible to create. Clock Types Although the clock synchronization option is not what you might call prevalent in synthesizers, you will find a feature called “Clock Division” somewhat more often. This option lets you subdivide the clock signal that you want to use for synchronization more or less as desired. Again, digital “virtual analog” instruments beat the “real thing” hands down when it comes to innovative features such as this one. For example, the Access Virus fea-

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Delaying and Fading LFOS In

tures a bunch of clock divisions, including “wacko” timings, modular systems such as the Native Instruments Generator or Clavia Nord Modular feature entire Clock Divider modules that let you enter any divisor for the clock, which of course gives you total freedom of choice. In newer synthesizers such as the ones I just mentioned, you will generally also find so-called MIDI Clock, which is also used for synchronization. MIDI clock is timing data that is generated in virtually all MIDI sequencers—be it software or hardware models. MIDI clock works with a resolution of 24 ppq (short for “pulses per quarter note”), which means just that—it generates 24 control pulses for every quarter note. If you unleash this clock on the clock rate without subdividing it, the results will generally be disappointing because the musical equivalent of 24 ppq is a 1⁄96 note. This means a control pulse is generated for each 1⁄96 note, which is—even in the era of techno—a bit fast for any musically sensible applications. Dividing values into lower, musically more desirable values takes nothing more than a simple mathematical equation: For example, if you divide by 6, you’ll get 4 pulses per quarter note, which is precisely what is customarily called a sixteenth note; divide by 12 and you’ll come up with 2 pulses per quarter note, i.e. eighths; divide by 8 and you have 3 pulses per quarter note, which is what musicians call triplets. The mathematically gifted who always did their homework and can still remember their division tables can easily figure out which time signatures other divisors will give you, the rest of us can always borrow a calculator. “Odd” values will often give you musically surprising results. Great stuff, huh—math that you can hear.

Delaying and Fading LFOS In Both the options of delaying the point at which an LFO kicks in—“LFO Delay”—and fading an LFO’s effect in gradually—“LFO Fade”—are artifacts of the era in which synths were purely imitators. The Delay function lets you postpone the point at which the LFO begins working its magic by a variable amount of time. The Fade function, a feature found solely on deluxe LFOs, blends the effect in softly. These functions are the culprits behind those dreaded Pan flute sounds which—after a second or so of

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8 LFOS

enjoying the thin Andes air—inevitably end in a vibrato that no Pan flute in this world is capable of producing. Don’t be put off by the past misdeeds made in the name of these functions. LFO Delay and Fade can, like all functions of a synthesizer, also be used for interesting stuff.

LFO Retrigger Normally an LFO is a free spirit, it oscillates away merrily regardless if you happen to be playing the synthesizer or not. With the “Retrigger” option, you can re-start it every time you hit a key. This feature is designed to give you control over at which point after you press a key or during which phase the modulations generated by the LFO (vibrato, trill etc.) are triggered.

Using Several LFOs As suggested earlier, a single LFO modulation with the same shape may soon sound lackluster. You’re already familiar with one possibility of animating the sound, i.e. modulating the LFO rate. There are more, provided your synthesizer is equipped with several LFOs. Polyphonic synthesizers usually feature one LFO per voice. You may not be aware of this fact, because they are inexplicably “concealed”—the waveform and rate of the individual LFOs cannot in most cases be controlled separately. However, if you don’t explicitly synchronize them, they will oscillate independently. This can produce really nice shimmering chords. Some synthesizers feature a parameter that generates a random variation of the LFO rate at different intensities. This feature will make chords sound even bigger. You win the versatility sweepstakes for LFO variations when your synthesizer features several LFOs to which you can freely assign modulation destinations. If you’re indeed lucky enough to own this type of synth, then you should try having one LFO modulate the rate of another. This guarantees absolutely random, totally unpredictable modulations that practically never repeat themselves.

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Which LFO Setting Generates Which Effect?

Another great trick that you can try when you have several individually controllable LFOs is generating what is called an “ensemble” effect. It lets you emulate expansive string sections, among other things. All you have to do is assign one LFO each to several oscillators and modulate the pitch of the oscillators with a slightly different rate. You’ll come up with more twisted effects if you assign different waveforms to the LFOs. Feel free to indulge in wild experimentation. Keep in mind that you can come up with anything you want, the idea is to have a good time while you’re learning the ropes.

Which LFO Setting Generates Which Effect? Now that you’re familiar with most terms that you’ll come across when dealing with LFOs, it’s time to take an in-depth look at the sound-shaping effects that these components can achieve. Vibrato Vibrato, a pitch modulation, is certainly the effect that LFOs are most often used for. This has more to do with the dearth of alternatives rather than the fact that an LFO is particularly well suited for the job. All you have to do is listen to the incredible range of expressive nuances that for example a good guitarist or violinist can coax from the respective instrument. When you compare this type of singing tone—you know when the player is truly “emoting”—with the sterile-Weebles-wobble-but-they-don’t-fall-down type sound of the LFO, you’ll know exactly what I’m talking about. There are methods by which you can use specific controllers to play a more masterly vibrato, but more on this in a later chapter. These tools require a fair measure of tactile dexterity, so be prepared to take the phone off the hook and woodshed for a while. It’s hard work getting vibrato right, but the good news is that you won’t have to give up your day job to get it down pat.

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Anyway, you nevertheless should know how to generate vibrato using an LFO, so let’s get to it. Chose either a sine or triangle waveform, select a relatively fast rate and assign the LFO to the pitch modulation input of the desired oscillator and presto, there you have your vibrato. CD track 24: Vibrato—here and in the following LFO examples, the LFO rate is controlled via an envelope.

Tremolo Tremolo is a modulation of the volume of a sound. This should tell you that you want the LFO to modulate the amplifier (VCA). Select either a sine or triangle as your waveform and set the rate to taste. CD track 25: Tremolo

Chorus Effect with PWM We discussed a trick earlier where you can use several oscillators and LFOs to make a sound wider and fatter. You can achieve a similar effect with just a single LFO and oscillator, if the oscillator features a pulse wave and the option of modulating it (PWM). Here too a sine or triangle should be the LFO waveform of your choice. What rate you dial in is entirely up to you; try different settings to hear what sounds best. CD track 26: PWM

Trill To generate trills, select a square wave as the LFO waveform and unleash the LFO on the pitch of the oscillator. The rate that you set determines the speed at which the two pitches that make up a trill alternate. CD track 27: Trill

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Which LFO Setting Generates Which Effect?

Auto Panning If your synthesizer is equipped with several outputs and a panorama parameter with a modulation input, you can use an LFO to make the sound “sweep” automatically from one output to the other. The selected LFO waveform determines if the sound moves relatively smoothly from one side to the other (sine oder triangle), or if it to some extent jumps back and forth (square). If you get bored with an effect that sounds like a gradual, even sweeping motion, try modulating the rate of the LFO that you’re using to create an auto pan via a second LFO. This will give you a more random and thus less predictable effect. CD track 28: Auto-panning with different LFO waveforms

What Other Tricks Are LFOs Good for? Well, a whole bunch. You’re limited only by your imagination and eagerness to experiment. Let both go haywire, you’ll end up having big fun with these at first glance less than awe-inspiring features. But take heed, LFOs are habit forming. You start out with one or two a day, soon these can’t satisfy your craving and before you know, you have a monkey on your back craving more LFOs. When you get to the habitual stage, you’ll have no choice but to go with a modular system: This breed of synth gives you virtually unlimited freedom in terms of the amount of LFOs and routing options. Here are a few tips to help you get started: ❖ Sic an LFO on the filter cutoff. Depending on the waveform, you’ll get anything from smooth, gradual (sine or triangle) to radical, abrupt (square) changes in timbre. ❖ If you use a square LFO to modulate a VCA, a played note is repeated constantly (Auto Trigger). Set the tempo of the repetitions via the LFO rate. ❖ Send a saw down to a VCF and VCA simultaneously to generate an auto trigger effect with a decaying curve. An ascending sawtooth accomplishes exactly the opposite, the sonic results can best be described as a “backwards effect.” CD track 29: a. LFO to filter cutoff, b. square LFO to VCA, c. descending sawtooth to VCF and VCA

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9 Playing and Controlling Synthesizer Sounds Now you’ve had a first look at the components that make up synthesizer sounds. However, a synthesizer that had nothing more to offer than these could hardly be considered “playable” in a musical manner. For example, how do you make the instrument do something as trivial as generate a specific note with a certain pitch at the desired moment or stop it from doing the same at another? How do you exert influence on modulations such as vibrato so they only occur in the desired musical scenario? These of course are questions that synth designers answered long ago by equipping their devices with a number of data input tools and control features.

Keyboard Undoubtedly the most important interface between man and machine is the synthesizer’s keyboard. Although strictly speaking, the term “keyboard” of course refers to the row of keys used to communicate with the device, it has become a synonym for “synthesizer” and synthesists are often called “keyboardists”. Although generally people don’t distinguish between the two, there is a huge difference. Being able to play standards on the piano may make Joe Blow a big hit at the office Christmas party, it doesn’t necessarily mean that he’s a gifted electronic musician and synthesizer player.

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What’s more, even if you don’t know the first thing about playing other instruments equipped with keyboards, this doesn’t stop you from creating music on a synth, even very good music. If you feel you’re not the most fabulous player on the planet, no worries, you will still have plenty of fun. The next time a real “keyboardist” gives you flak about your chops, simply give him a dose of reality in the form of a Joe Zawinul quote. The great man himself noted in an interview with the German magazine “Keyboards” that he was “unfortunately just a piano player, not a synthesizer player.” A brief trip down synthesizer memory lane tells you that the marriage between electronic sound generators and a keyboard of the type found on pianos and organs wasn’t preordained. Instead, inventive designers used every manner of imaginative implements, from bastardized typewriter pads to a set of antennas between which you can play mad conductor or wires that you have to press onto a metal track. People have come up with all kinds of contraptions, some wildly unlikely, for coaxing sound from electronic instruments. Why the keyboard lastly came out on top was perhaps because it was the most pragmatic option, both in technical and pecuniary terms. Basically, the great advantage of the keyboard in the early days of commercial synthesizer building was that the keyboard already existed as an input medium for musical information—it thus didn’t have to be developed and built from scratch, which would have cost time and money. Then there’s the fact that from an engineer’s point of view, a key is a nothing more than a straightforward switch, and one that works well at that: When the key is pressed, a contact is made, thus establishing an electrical circuit. When the key is released, the contact is severed and the circuit goes dead. This simple concept, coupled with the fact that the pattern of the keys and thus arrangement of the notes is logical and easy to grasp (just compare it to the way notes are arranged on the fretboard of a guitar if you have doubts) and an ergonomically proven design that seems predestined for human fingers, you can see why the keyboard as we know it won out over all the other gadgets.

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Keyboard

As you’ll soon find out, today you can do many more wild and wonderful things with a keyboard. Back in the days of the Minimoog, things were a bit different, you could use the keyboard only for … Controlling Pitch When you press a key on the keyboard of a voltage-controlled keyboard, two things happen: ❖ First of all, a trigger and gate pulse is released that start up the amplifier envelope generator. The oscillator signal, which constantly hangs out at the input of filters waiting to get in, finally gets the go ahead to “set foot” into the filter, then on into the amplifier controlled by its envelope. The latter runs through the attack and decay phase and stays at the sustain level until you tell it to get lost by releasing the key. It fades out during the predetermined release time and then disappears. ❖ The second process that occurs has to do with the specific voltage value assigned to each key. This voltage is sent to the VCO to determine the frequency of the signal, in other words the pitch of the note that you are playing. The majority of voltage-controlled synthesizers work with the basic value of 1-volt/octave. This means that the difference from one key to the next is always equal to exactly 1⁄12 of a volt. The oscillator runs on the same principle, so it “knows” precisely which pitch it has to generate for which key you press. In most analog synthesizers, pitch control works along these very basic lines: A half-tone step on your keyboard is equal to a half-tone change in pitch. This however is not The Law, you can pull some nifty tricks with control voltages. There are some synthesizers that let you define pitch intervals other than half-tone steps, for example quarter tones for that sound to go with your Chicken Tikka, whole tone steps, no transposition whatsoever; you can even “mirror” the entire keyboard. The keyboards of modern digital synthesizers are of course a different, more advanced breed altogether. Here the keyboard is sampled by a digital component, which when you press a key, registers a “MIDI Note On” command as well as a specific “MIDI Note Number.” It is sent to the sound

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generation section to determine the desired pitch. As you are presumably aware, the number of options for manipulating data generated in this manner are exponentially higher than the few tricks you can do with voltage-controlled keyboards. The fact is that it’s much easier to bend digital data than to physically change electrical charges. What Is the Difference Between a Trigger and a Gate? Although you are constantly confronted with these two terms when you’re dealing with synthesizers, you may not be aware of the difference between the two. ❖ A trigger does exactly what the name implies: it is a single pulse that “fires off” an event. For example, if a trigger is sent to an envelope, it causes the envelope to start. ❖ The aptly named gate does the same thing except that it distinguishes between the conditions “open” and “closed” The keyboard of a synthesizer works on the gate principle: If you press a key, the gate opens and remains open for as long as you hold the key down. It closes when you release the key. Sounds absurdly logical, doesn’t it? Well, here’s where the confusion starts: The process of opening a gate by pressing a key is also called a “trigger.” When you’re dealing with envelopes, you thus run into several “trigger modes” which let you determine how the envelope responds to an open gate. Generally, synths distinguish between two modes: ❖ In “Single Trigger” mode, the envelope is started by the first note that you play. All other notes that you play while holding the first note do not restart the envelope—it inexorably runs its course. The Release phase doesn’t start until all keys are released. ❖ In “Retrigger” or “Multi-Trigger” mode, every note that you play restarts the envelope.

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Monophonic and Polyphonic Synths After your first ten seconds of messing about with a synthesizer, you probably already discovered some of the fundamental differences between it and a piano. This may have been one of them: If you had the genetic “gifts” to press all 88 keys on a piano at the same time, you would hear 88 notes sound at the same time, each with its very own properties such as timbre and response. On a synthesizer, the number of notes that sound simultaneously depend on how handsomely appointed your box is; in other words, how many voices it has (polyphony). Each note requires a synthesizer voice—a complete set of oscillators, filter, envelopes, LFOs and all the other knickknacks that a particular synthesizer has. This is the only way that each note can have its own timbre and response. To make synthesizers more affordable, some earlier synthesizers were polyphonic in design, but featured just one filter amplifier module; the Polymoog and Korg Poly-800 were among this breed. Even if you played an arpeggio, everything had the same sound and volume. This solution was not immensely satisfying, so you won’t find any newer devices based on this principle. In true analog synthesizers, each voice is comprised of real hardware. Every module has to be implemented using physical components. The less expensive synthesizers of yore were monophonic—which means they had just a single voice. The first polyphonic—i.e. multi-voice—synthesizers remained in the hands of professional players. They were simply too expensive for players who were into synths for the fun of it. A Polymoog or Oberheim OB-8 would have set you back a bundle, well over 10,000 DM. The polyphonic synths’ campaign of world domination was launched with the Korg Polysix. Although it only had six voices, it also had a price tag of around 4,000 DM, which was sensational at the time. To this day, analog synthesizers are generally equipped with eight to sixteen voices, except that today the number of voices depends on computing power rather than piles of components.

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These synthesizer can be switched to monophonic mode for playing solos or imitating melody instruments. This is a reasonable proposition when you want to use portamento—more on this in the next section—or all voices simultaneously for a single note. The latter mode is called Unisono and lets you come up with extremely fat, powerful sounds. Portamento/Glide Portamento—also called Glide—is a typical synthesizer effect generated by the keyboard. When you play an octave trill with portamento, the pitch glides back and forth gently rather than switching hard and abruptly. The time it takes to glide from one note to the next is called Portamento Time; it is infinitely variable. If you set a long portamento time for an octave trill, you will hear something similar to the sound of a siren. Most synthesizers let you select two special portamento modes: ❖ Fingered Portamento—here the pitch glides between two legato notes only. This effect lets you play typical synth solos. ❖ Glissando—here the pitch glides in half-tone steps rather than seamlessly. You can dial in settings where these are played at a speed than even the most nimble-fingered shred demons could play chromatically. CD track 30: a. Portamento, b. Fingered portamento (Legato portamento effect)

Key Tracking “Key Tracking,” also called “Key Follow,” is a modulation source that is closely linked to the keyboard. The values generated by this function are determined by the position of the notes on the keyboard. Key tracking can in most cases be assigned to all manner of synthesis components, whereby you’ll notice that the feature was definitely designed to support the imitative talents of synths. In other words, key tracking is a relic from the days when the raison d’être of analog synthesizers was to ape acoustic instruments. You’ll have to judge for yourself how much key tracking can contribute to non-imitative sounds. In any case, it would certainly be helpful if you know what it actually does.

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Velocity

❖ The vibrations of the oscillator double their frequency in parallel to the pitch. This effect can in some cases produce an undesirable “wobbly” sound, as if the tuning were slightly off. To compensate for this effect, assign a key tracking value of 99 % instead of 100 %. ❖ When you play instruments such as piano or guitar, you may have noticed that the higher the notes, the less the natural sustain. The VCA envelope couldn’t care less, so you’ll have to mimic this property if you’re going for a “natural” sound. This is a task for key tracking. ❖ Pitch (vibrato) or pulse width modulations are perceived more readily when they’re applied to lower notes. If you assign key tracking to the rate or intensity of LFOs, you can either amplify or compensate for this effect by linking the parameters to specific areas of your keyboard via key tracking. ❖ Many acoustic instruments sound ever brighter as the notes get higher. If you assign key follow to the filter cutoff frequency, you can have your analog synthesizer emulate this phenomenon. Key tracking can also be used to ensure the sound remains the same over the entire range of the keyboard because the relationship between the fundamental tone and the cutoff frequency does not change.

Velocity “Velocity” is an effect that you won’t find on too many vintage model synthesizers. If you take a closer look at it, you’ll see why—this is a pretty sophisticated effect. The speed or velocity of each key as it is pressed has to be measured. This value is then used to generate control information. In the era of digital technology, implementing this effect doesn’t give engineers sleepless nights, which is why this feature is ubiquitous today. Even though velocity was certainly invented to improve the imitative capabilities of the instrument—we all know that the harder you pound on a piano’s ivories, the louder the notes will be—you shouldn’t use this effect for every sound, all the time, to make it respond to your touch. You’ll find that most synth basses, organ noises and a lot of other sounds don’t benefit much from velocity. Also, it can really wreak havoc on your “feel” for the instrument.

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Fortunately, the options that modern synthesizers offer in connection with velocity are overwhelming. Go ahead and take the phone off the hook, lock the door and ignore your email messages. It’s time to experiment. While you’re at it, try to forget about what it was originally designed for and consider it just another option for generating control data. Aftertouch Aftertouch is another innovation that didn’t become a “household” feature until fairly recently; it is found relatively rarely on older models, whereby the Moog Multimoog immediately comes to mind as one of the exceptions to the rule. Generating aftertouch data is another relatively sophisticated endeavor: one or several pressure-sensitive sensors located under the keyboard measure how hard you bear down on the keys after you have pressed them and forward this data to where ever you want to use it. Synths distinguish between two types of aftertouch: ❖ “Channel Aftertouch,” also somewhat confusingly called “Monophonic Aftertouch” generates data according to the values it measured most recently. In other words, this version of aftertouch can only generate a single value at any given point. ❖ The deluxe version of aftertouch is “Key Aftertouch,” also called “Polyphonic Aftertouch.” Here the value for each key is measured individually, thus a separate value is generated for every key and pitch. Keyboards that can generate polyphonic aftertouch are few and far between, sound generators that can process polyphonic aftertouch data are more common. Why am I mentioning this? Bear with me, you’ll soon find out in section “Using Keyboard Data without a Keyboard” on page 87. Presumably, the designers who came up with aftertouch developed it so that synthesizer players could generate nifty effects such as vibrato or control the filter cutoff without actually having to set down the beer in their left hand—which to this day is certainly a compelling reason to use this effect. Other than being a truly valuable contribution to handling comfort, the polyphonic version of aftertouch is the only keyboard control parameter that can be assigned to individual notes, which makes it just as valuable for those who don’t imbibe.

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Release Velocity Release Velocity is also a relatively uncommon feature. Here a scanner measures how quickly you release a key. This data can then be used as modulation values. This feature is rarely used in realtime—even players with wicked chops and a masterful touch find it hard to precisely control the velocity at which they release keys. But this doesn’t mean release velocity is entirely impracticable; it is actually a pretty cool programmable parameter in sequencers. Using Keyboard Data without a Keyboard As you were browsing through this chapter, you may have noticed that a keyboard is capable of generating a pretty impressive range of control data. You may have even taken this thought a step further and wondered who on Earth is capable of playing of the instrument to take advantage of all these options. Well, in my experience, the answer is no one. I have yet to meet a keyboardist—and I do know a few where the term “virtuoso” is no exaggeration—who was able to create something of lasting significance with a tool such as release velocity. “Non-keyboardists,” whom I have a real soft spot for (especially since I consider myself a member of this tribe), find it hard enough to control a given parameter via velocity. Nevertheless, even less gifted players can use the data that a keyboard is able to generate to great effect. The secret to it all is the sequencer. All data that a keyboard generates can also be generated in modern sequencers— be it the hardware or software variety—using a keyboard or mouse as your input tool. If you know exactly what you want to achieve in terms of music and sounds or if you are willing to experiment, you can often come up with a more compelling, innovative track than even the most advanced playing can produce. Even if you’re one of those players with blazing technique, a sequencer gives you plenty of options for creating more interesting sounds. For example, what good is it if you—despite the fact that it’s four in the morning and you are in a severely altered state of mind—are still capable of playing accurate renditions of all of Czerny’s études when your control keyboard is unable to generate the polyphonic aftertouch data that you

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need to control a particular parameter? (Remember, other than velocity, this is the only modulation source that can generate separate data for each note!) The only reason to attempt this kind of stunt at this hour and in this condition is to impress someone you’ve just met who for whatever reason needs to be overwhelmed with the depth of your artistry, so if you’re the sort that plans ahead, you programmed the requisite data in your sequencer for just such an occasion. Are There Good and Bad Synthesizer Keyboards? If you’ve caught a serious synth bug, you’re probably an avid reader of keyboard mags. Often these publish benchtests that its editors conducted on the actual piano-like keyboards. In terms of analog synthesizers, be sure to take these evaluations with a grain of salt. An 88-key wood keyboard with hand-made piano levers will undoubtedly earn highest ratings, but it certainly wouldn’t be your best choice as the control tool for an analog sound generator. Although in terms of mechanical and technical excellence, a Minimoog keyboard is a crude joke compared with one of these handmade beauties, it is nevertheless a much better tool for playing synth sounds. When you’re contemplating spending your hard-earned on a synth, keep in mind that a more important consideration than the “objective” qualities of a keyboard is whether or not the synth has one at all! Say you’ve fallen in love with a particular model: Given the choice between a version with keyboard or a version without, always go for the keyboard version. Nothing is a greater damper on your creative drive than playing sounds (see next chapter) when you have to contort yourself to make the stretch between a keyboard and a remote sound generator. In contrast, if you can bang away at the keys in a relaxed state and simply lift your hand up a few inches to twiddle knobs, your fun factor will increase exponentially.

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Controllers

Controllers Next to the keyboard, over the years a number of tools were developed that let you influence synthesizer parameters in realtime. All of these gadgets are inventively called “controllers.” Some came and, because they were wildly impractical, went, others have established themselves as real “tools of the trade” that any synthesist worth her/his salt wouldn’t want to miss. For a creative player, these are among the most important features, and to be honest, most feel that there are not nearly enough of them around.

Axel Hartmann

Wheels

The wheels of a synth in classic array: to the left the pitch, at the right the modulation wheel

Since the days of the Minimoog, “wheels” are standard features on most synthesizers. On the average synth, you’ll find two of these rotary control features, a “Pitch Wheel” and a “Modulation Wheel.” Their names are pretty much self-explanatory, at least in terms of what they were originally designed for: the former serves to control pitch in theoretically infinitely variable increments—a procedure generally called “pitch bending”—and the other is used to control modulations such as vibrato. Whereas the modulation wheel’s zero position is located at the bottom of the wheel and

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its maximum setting at the top (picture an over-sized rotary knob flipped on its side), the pitch wheel has a center detent and equipped with a spring-loaded mechanism that automatically returns it to this center position when you release the wheel. As the digital revolution swept the synth world, wheels began to be used to control stuff other than just these original two parameters. On modern synthesizers, you can manipulate virtually every parameter via a wheel. Things get really hip when you can assign several functions to the wheel and execute them simultaneously—this handy feature actually lets you “play” sounds. Pedals and Foot Switches Synth designers, possibly inspired by traditional church organs, thought to exploit the fact that we multi-appendage creatures come factory-equipped with two feet and came up with a bunch of pedals and footswitches to control the instrument. The former generate continual data streams and the latter trigger and gate signals. On classic synthesizers, these usually have fixed parameter assignments, but since the arrival of MIDI, you can use them for controlling practically any function that tickles your fancy, which is a nifty option indeed. Ribbon Controllers A Ribbon Controller is simply a touch-sensitive strip. Long ago, the ribbons were made of wire mesh or velvet. Today these tend to be made of more hygienically-correct plastic. On vintage models, when you ran your finger down the ribbon, you changed the value of a resistor, which the synthesizer converted into a control voltage. Today a digital component captures data indicating the position of your finger and generates control data based on this information.

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Controllers Abbildung Moog Multimoog

On the Multimoog, which incidentally contributed many of the audio examples on the CD, one wheel was replaced with a ribbon controller.

You will come across two types of ribbon controllers: The more common version works with a definite center position; you can feel the raised spot when you run your finger across the ribbon. From this point, you can move to the left or right to decrease or increase values. With the other model of ribbon, featured for example on the Yamaha dinosaurs CS-60 and CS-80, where ever you happen to place your finger is defined as the starting point for manipulating values. For the longest time, ribbon controllers were nearly extinct, but recently they have enjoyed a renaissance of sorts. The company Kurzweil even makes a “stand-alone” MIDI ribbon—albeit an expensive one—that can control practically every parameter of a MIDI-capable synthesizer. Ribbons have a distinct advantage over wheels: Because you can place your finger directly on any desired position, you can “jump” parameter values, for example to generate trills when you’re controlling the pitch via a ribbon. Anyone who has had the opportunity to work with a ribbon will confirm that this is a pretty flexible tool for “playing” sounds.

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Axel Hartmann

Lever

The lever, a more infamous than famous controller

The “Lever,” occasionally called a “Bender” in reference to the inscription indicating what it does, is a controller that you’ll most often find on synthesizers sporting the Roland brand. Here two functions—pitch bending and triggering a modulation—are executed via a single control feature. When you move the lever to the left, the pitch is lowered; moving the lever to the right increases pitch. Pushing it forward triggers or fades in a modulation. A spring-loaded mechanism ensures the lever returns to its center position when you release it. Now for another tirade: The lever is a controller that—no matter how much you are willing to give it the benefit of the doubt—you will ultimately end up cursing. Granted, after you have practiced enough to get a “feel” for the gadget, it does let you achieve some nice pitch modulation effects. But talk to any Roland user and they’ll set you straight: It is extremely difficult to bend the pitch and control a modulation at the same time subtly. On older model levers, your options for modulation control are to one: triggering. In other words, the lever works exactly like an “On” switch, which you’ll agree is not the most thrilling function imaginable.

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Axel Hartmann

Joystick and X/Y Pad

The joystick, a tool for two-dimensional parameter control

The first time a Joystick cropped up as a controller was on the legendary VCS 3 by EMS. The Korg people obviously thought it a dandy gizmo because it later appeared on a slew of the company’s synthesizers. The Korg joystick usually works along the following lines: The horizontal trajectory (left, right) of the stick is responsible for pitch bending and the vertical (up, down) controls other modulations (e.g. LFO or filter cutoff). A spring-loaded mechanism returns the stick to its center position when you release it. The fixed assignment of the pitch bending function robs the joystick of its potential for versatility, which is possibly why many musicians, when asked to comment on the gadget, mutter something unintelligible or unprintable. If you want to find out how handy, even cool, a joystick can be when it is freely assignable, simply check out that old workhorse, the VCS 3. In more recent times, the notion of a two-dimensional, freely assignable tool was revived in the form of the X/Y pad as found on the Korg Z1. This X/Y pad is something of a cross between a joystick and a ribbon controller. Depending on the position of your finger on a touch-sensitive plastic panel, you can control parameters assigned to the horizontal and vertical levels, whereby you can achieve really nice gliding effects. Now if this pad could only gauge the amount pressure applied to it by your finger, you would have a three-dimensional controller!

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Breath Controller The Breath Controller, a favorite source of off-color jokes among synthesists, is an innovation for whom we have the imaginative people at the R&D department of Yamaha to thank. Here you blow into a mouthpiece and a converter that gauges air pressure and changes it into a control value. In theory, this is a pretty hip controller because it gives you yet another option for manipulating synthesis parameters beyond those handled by the four standard-issue human appendages. Also, it is very responsive, allowing subtle control of effects. In practice, there are some serious image-related drawbacks: First of all, the gadget seems to promote saliva production and it doesn’t take long for you to resemble Cujo (no headbanging in public, please). Then of course there’s the nearly insurmountable problem of looking cool with something resembling an over-sized pacifier in your mouth. Finally, as you get into the groove of things, the Dizzy Gillespie factor may crop up, puffy cheeks and all.

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10 10 Advanced Synthesis Features and Gear With the information discussed in the chapters you’ve read thus far, you should now be able to find your way around an analog synthesizer, or, at the very least, have a basic idea of what the different parameters do. In the following chapter, we’ll take a look at some features that are not part and parcel of every synthesizer under the sun. Many of these are either rarely found on hard-wired synthesizers or not at all. You’ll have to check out modular systems—which after reading this chapter you will be raring to have a go at—to enjoy the benefits of these. Keep in mind that you don’t have to shell out big bucks for a Nord Modular or CreamWare Scope, not to mention a Moog 55 or ARP 2500 to have fun. Purely software-based systems such as the Native Instruments Generator give you the same features—albeit in a virtual package—without having to mortgage your house. You see, computers are good for something after all: they’ll give you a relatively big bang for your buck.

Using an Oscillator as a Modulator You already know that LFOs can be used to come up with effects a great deal wackier than run-of-the-mill vibrato and tremolo. If you’re into making big noise, try modulating an oscillator with another audio oscillator. You can turn seemingly harmless waveforms such a square or sawtooth into the worst kind of snarling monsters. You can take the whole thing into the realm of overkill when you modulate the oscillator that’s doing the modulating. Here a normal LFO can give you pretty wild results.

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The same holds true for modulating filter parameters—the cutoff, resonance or even both for each audio oscillator: nasty, nasty, nasty.

Using Your Synthesizer as an Effects Device Early on, intrepid musicians saw the potential of synthesizers and began abusing them as effect devices for other instruments, voices or whatever. The only prerequisite is one or several inputs that let(s) you patch in external audio signals. These can then, depending on the synth, be processed by a few or a number of synthesis components. For example, you could only use a Minimoog’s filter and VCA for this purpose, with modular systems and newer virtual analog synthesizers such as the Access Virus, your options are anywhere from substantially greater to near infinite. One of the more popular tricks of electronica freaks is to route drum or sequencer loops or even entire tracks to synths and modulate them to their heart’s content. You’ve heard the computer adage, “Trash in, trash out?” Well, here in many cases quite the opposite holds true: boring in, exciting out.

Envelope Follower An envelope follower is patched in after the external audio input of a synthesizer. It converts the level curve—the envelope—of an incoming signal into a control voltage. You can assign this control voltage to any synthesis parameter, which is then modulated according to the level of the audio signal. For example, if you turn it loose on the VCA, you can control the dynamics of the synthesizer. Unleash it on the filter and you can use the control voltage to generate universally loved auto-wah effects and similar stuff. CD track 31: Envelope Follower: The amplitude of the drum loop signal controls the cutoff frequency of the filter through which the drum loop is being sent (auto-wah).

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Pitch-to-Voltage Converter

Pitch-to-Voltage Converter A pitch-to-voltage converter is a module rarely found in synthesizers. It analyzes the pitch of an input signal and generates a control voltage based on this value. Usually it is coupled to an envelope follower which generates the trigger and gate signals. Theoretical purpose: You could conceivably control a synthesizer via voice, guitar, nose flute, idiophone, kazoo or another sound source that is capable of generating single notes. Practical result: Ask anyone who ever played on an early guitar synthesizer equipped with pitch-to-voltage converters. They all sing the same song, that glitches and erratic tracking were the norm. One of the major problems of these devices was that the converters had trouble identifying the pitch whenever the signal level dropped below a certain level. If you’re one of those musicians with a zeal for experimentation and you run across one of these less than brilliant guitar synthesizers at a garage sale or pawn shop, by all means go for it if you can get it for a steal. Take it home, plug in a microphone and do the Karaoke thing. Although the box will rarely do what you expect it to, on your quest for bizarre sounds, it may take you to some strange places; not necessarily wonderful, but definitely strange, which is cool too.

Sample & Hold This module is also often call a “Random Module,” which strictly speaking is not quite accurate. A sample & hold module takes a sample of the incoming signal at definable intervals, holds this value and routes it out of the module as a control voltage. You can then use this voltage to control all manner of parameters. What the sample & hold module does is carve a step into a normally continuous signal; the depth of this step depends on the interval between two “samples.”

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If you use an LFO waveform as the input signal and the module’s output signal to modulate the pitch of an oscillator, then depending on the settings, the sequence that is generated sounds rather random, but it actually isn’t. A stickler for accuracy would say that the actual oscillation of the LFO doesn’t change, so the effect is predictable. The only time the results are truly random is when you select noise as the input signal. Next to the oscillator frequency, a popular modulation destination for this effect is the filter cutoff frequency, in which case, rather than the pitch, the timbre of the signal changes in sync with the clock of the sample & hold module. Here’s something you can try at home: On modern synthesizers, you can often feed MIDI clock to the module. Then the effect will be in sync with the sequencer—which can produce some pretty wicked grooves. CD track 32: Sample & hold: near random pitch variations

Formant Filter A formant filter is inexplicably one of those awe-inspiring components, which when synth freaks get to talking about it, the volume of the conversation drops to a suitably hushed whisper. Don’t be fooled, a formant is as easy to understand as it gets; it’s nothing more than a fixed frequency. If you want to call a spade a spade, then the formant filter is a filter with a predefined invariable cutoff frequency. This isn’t very impressive, but it is easy to understand and at least as correct as the more esoteric explanations that you’ll come across. Presumably, the reason that it became famous and the stuff of legends was the formant filter bank of the Moog 55, which was equipped with a whopping fourteen formant filters featuring variable amplitude. The best and surely most common example of formants is the human voice. It comes factory-equipped with formants, i.e. frequencies that never change, regardless if the pitch of the voice changes or not. These are responsible for the fact that each voice has its own timbre that is as unique as a fingerprint.

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Vocoder

Vocoder A vocoder is scarcely a standard issue feature of synthesizers, at best you’ll find it on board the rare modular system. Vocoders usually call a dedicated, stand-alone device home. In a nutshell, a vocoder lets your sounds do the talking for you. The majority of “robot” voices that you may have heard were generated via vocoders. So how does one of these synth-based talk-boxes work? Actually, the principle is pretty simple. A vocoder requires two signals to work its magic: a so-called “carrier” signal and a “speech” signal. The speech signal is piped through a section of the vocoder that dissects and analyzes its component parts. Based on the results of this analysis of speech data, the synthesis section of the vocoder reconstructs the carrier signal so that it mirrors the structure of the speech signal. vocoder

The legendary EMS Vocoder 5000.

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For you trivia buffs, the first vocoder, built in 1940 by the famously named US engineer Homer Dudley at the renowned Bell Laboratories, was not developed with a musical purpose in mind. It was a part of a series of experiments to research ways of compressing the human voice for transmission via the then standard copper-wire cables. It wasn’t until much later, 1948 to be exact, that the German phonetician Werner Meyer-Eppler discovered that the machine was suitable for making electronic music. The electronic and mechanical components that comprise a vocoder are fairly basic. If you have a handful of band pass filters, envelope followers, amplifiers and an oscillator for generating the carrier signal—all soldered together at the proper spots, you’re ready to roll: ❖ The speech signal is routed to the analysis section, where it is piped through a series of band pass filters characterized by steep slopes. ❖ Each of these band pass filters’ output is routed to an envelope follower, which generates a control voltage based on the level of the incoming signal. ❖ In the synthesis section, the carrier signal is also patched through a series of band pass filters with steep slopes. The number of filters and their cutoff frequencies in this section are exactly the same as those in the analysis section. ❖ However, these filters are each followed by a VCA controlled via the voltage generated by the corresponding envelope follower in the analyzer. This is how the speech signal “voices” the carrier signal. If you take a look at the illustration below, it should clarify anything that might still be unclear to you about the design of a vocoder. The high pass filter indicated in the diagram has a special purpose: It routes a portion of the original speech signals directly to the output to improve the intelligibility of the carrier signal. Vocoders had their Warholian fifteen minutes back in the taste-challenged Seventies. With just a few exceptions—Kraftwerk being a notable one— they weren’t used for their unique tonal aesthetics, but instead to make vocalists of instrumentalists that under normal circumstances wouldn’t have been let anywhere near a live mic: The “artist” talked into the device

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Step Sequencers

and used a keyboard to control the pitch of the oscillator that generated the carrier signal—voilà, the machine suddenly sang. Because even the best vocoder was unable to reproduce a voice 100 % accurately—the device always added a very unmistakable synthetic coloration—audiences soon grew weary of the vocoder sound. No longer the flavor of the month, the instrument all but disappeared from the scene for many years. Techno, a style played by musicians known for their willingness to experiment, was lastly responsible for the rediscovery of the vocoder. The protagonists of this style of electronica are typically unconcerned with what something was designed for, they use technology for the sole purpose of having fun with it. These players fed the vocoder with all manner of signals instead of voices and used sounds other than what you might call standard for carrier signals. Suddenly the vocoder metamorphosed into one of the most interesting sound manipulating machines imaginable. Fortunately, now that it is back in vogue, vocoders have become readily available, some with a price tag that lets less affluent musicians take one home: Opcode offers a software plug-in for Macintosh and PC, Digitech has a device called “Talker” which sounds interesting but is not cuttingedge in terms of flexibility. For really hip, highly versatile vocoders, check out the modules in the Clavia Nord Modular and Creamware Pulsar and Scope. If you are taken aback by the price tag of these systems, keep in mind that a good analog vocoder by EMS or Sennheiser costs about the same as a good economy car or even a decent mid-size. Sure, the vocoder gets better mileage, but try taking out a date in it. Again, the virtual analog synths come out on top in the bang-for-buck stakes. CD track 33: Vocoder (carrier: poly synth), speech signals: a. drum loop, b. human speech

Step Sequencers Even if step sequencers have nothing whatsoever to do with sound generation, a book on analog sound synthesis that didn’t at least touch on this topic would be missing the point. For one, the history of voltage-controlled synthesizers and step sequencers, called analog sequencers by some, are inseparably intertwined. For the other, step sequencer hitched a ride on the coattails of the analog synthesizer and also enjoyed a renaissance of

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sorts. Today, many electronica freaks would rather part with their mates than their step sequencers, and to hear tell, the “either-it-goes-or-I-go” scenario isn’t all that uncommon in households where the synth bug has found a home. korg sq-10

The Korg SQ-10 was a no-frills analog step sequencer, but it certainly had plenty of knobs—one for each parameter of every step.

Before I try to explain how one of these works and presumably get it terribly wrong, let’s learn by doing. Join me as we build a step sequencer of our very own. First of all, we need a bag full of control voltage sources (say sixteen, which sounds like a real musical value) and set these up all pretty in a row. These are our “steps.” Now we’ll connect them to a clock oscillator (for example an LFO that puts out a square) so that each pulse of the clock oscillator selects the next step. Basically, that’s all there is to it, except that it might be nice to hear what’s going on. Ergo we’ll route the signal of each “active” step to an oscillator. It would also be helpful to generate different pitches for the different steps, so we’ll make the control voltage of each step variable, and for ultimate handling ease, we’ll drop in a rotary knob for just this purpose. Presto, your step synth is ready to do its thing. For the icing on the cake, we’ll teach it to start back at Step 1 when it has run all the way through Step 16, a little trick called a “Cycle” function. Now it will noodle away merrily until judgement day. So far, so good? I thought so.

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Step Sequencers ro_tb303.tif

This bass synthesizer with step sequencer is eternally hip—to this day, the Roland TB-303 Bassline sets the standard in terms of sound and sequencing coolness.

Not willing to leave well enough alone, let’s add a pinch of spice to the stew. We’ll drop in another control voltage source to each step and make these variable via rotary knobs. Next, we’ll connect the outputs of this row of components to the cutoff modulation input of the filter—now we can manipulate the timbre of each step. “Hey,” you say, “what about controlling the volume of each step?” No problem, simply add another row of variable voltage sources and route these to the VCA—voilà. Now if we access all three control voltages and use them to manipulate the frequencies of three oscillators, we can even generate chords. Although we have built a fairly simple apparatus, it certainly is versatile. With an attention span honed by the 30-second sound bite, we’re already anticipating that our sequencer might become monotonous after while. Fair enough, so we’ll reach deep into our bag of tricks to keep ourselves entertained: You can of course modulate the clock generator (foresight being one of our strengths as DIY designers, we used a standard LFO) and thus create syncopated or even totally arhythmic grooves, if this isn’t a contradiction in terms. If we modulate the clock oscillator via another row of knobs which

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are sampled step by step, then exactly this pattern is repeated in every cycle. If instead we modulate the clock oscillator via an LFO, sample & hold module or an envelope, then the whole thing takes on an unpredictable life of its own. Mind you, what I’m on about here is not pure conjecture or theoretical musing, you can actually do exactly what I’ve described here. If you own a modular system—to belabor the point, an inexpensive one such as the Generator by Native Instruments will do just fine—you can build a sequencer just like we described. To make sure I wouldn’t lead you astray, I followed my own instructions using my Modular; lo and behold, the sequencer actually worked. To see how incredibly flexible an analog step sequencer can be when its makers pull out all the stops, we’ll check out a few of the features of the possibly most lavishly appointed model of this breed of device ever made, the “Touch Activated Keyboard Sequencer” by Serge: Among a host of other stuff, you can interactively change the length of the cycle while it is running, use voltage-control “commands” to step forwards or backwards through the sequence and have the sequence start at a different position in each cycle. In recent years, very few step sequencers have been introduced to the market, and those that are available cost a bundle. Production is expensive because of these—as we’ve just experienced—require a bunch of hardware parts. Moreover, the market for these devices is just a tiny niche, so they’re manufactured in very small numbers. Worth mentioning is the SAM 16 built by Munich’s own Sebastian Niessen. You’ll have to dig deep in your pockets for this baby—it retails for US $ 2,500, and I have yet to see it offered on the second market for anything less than US $ 1,400. At some US $ 800, Notron by the British company Latronic is not as pricey, but in contrast to SAM, which features both MIDI and analog capabilities, it is purely a MIDI device. The good news is that its design is truly innovative. Then are some synths that feature really nice integrated step sequencers, e.g. the Yamaha AN1x or—in a modular package—the Clavia Nord Modular. Hopefully these will serve as an inspiration to other makers. We would all welcome it if step sequencers enjoyed a development

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Types of Effects

similar to what analog sound synthesizers are currently undergoing—a renaissance where designers aren’t satisfied to simply imitate vintage models, but instead use contemporary technology to improve on an already grand idea. CD track 34: Step sequencer with a tonal modulation

Why have musicians bothered to rescue step sequencers from oblivion? Well, for one, modern styles—from jungle to hip-hop and techno to drum & bass—thrive on repetitive elements, and as we have just seen, step sequencers are absolutely predestined for this type of application. Another fantastic advantage of these boxes is that they make it easy to work intuitively and be creative without requiring a great deal of experience in synthesis. To fiddle with and change a sonic sequence, all you have to do is turn this knob, maybe that one a tad, shift the start or end point of a sequence by a step, and presto, everything sounds totally different. And best of all, you can do it in realtime while the machine is running, which, believe me, is big fun.

Types of Effects This of course is a book about synthesizers, not a treatise on effects devices. Nevertheless, they are an important ingredient when you’re cooking up sounds, so in the following section we’ll take a brief look at some of the more common effects and check out what they do. Before we get down to business of discussing select effects, I’d like to share a few thoughts on these sound mangling options and how they relate to synthesizers. Although you might feel that these insights are a bit too philosophical and not enough “hands-on,” if you keep these in mind when you’re creating sounds, you will come up with substantially better, i.e. more unique, sounds—you have my word on it. Generally, there are two schools of thought when it comes to effects. In a nutshell, the one camp believes that a synthesizer sound is only valid if it sounds good without effects. In this mind-set, the actual sound and the effects are regarded as two distinctive components. Plus there is a certain

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touch of snobbery that relegates effects to a more or less subordinate role. It’s not uncommon for effects to be regarded as sonic “make up” with which incompetent sound programmers attempt to mask their short-comings. The other school regards effects as totally valid, fully equal components of a sound. From this point of view, the actual synth sound is no more than a lesser element of the greater sonic picture, and the only criterion is if the final product sounds good. Far be it from me to tell you how and what to think, but you might be better off contemplating the advantages of the latter attitude. Among the noted sound designer Helmut Kohl’s many incisive remarks was something to the end that the only thing that counts is what comes out in the end. Although in politics, this seems a dubious proposition, in synthesis, it’s sound advice. How you come up with what you have in mind is up to you, but the undeniable fact is that effects often make for more interesting sonic events. Then there is another aspect you should keep in mind: effects devices give you more options for “playing” sounds. You can manipulate effects parameters in realtime just like you can tweak parameters on your synthesizer. Thus under certain circumstances the knob that controls the delay rate of your delay device can be just as powerful a sound-sculpting tool as the cutoff knob of your synthesizer. Delay Delays, way back in the dark ages of pop often erroneously called “echo devices,” are possibly the most productive effects when married to synth sound. Some synths feature on-board delays or more accurately, delay modules, although generally this effect is housed in a dedicated peripheral device. A delay is pretty much self-explanatory; it lets you postpone signals by a variable amount of time (“Delay Time”) and have the device repeat these delayed signals a variable number of times. The effect has an incredibly wide range of possibilities—you can conjure up anything from the sonic ambience of a trash can (extremely short delay times of 20 to 70 ms),

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Types of Effects

through to creating wild grooves by playing just a few notes or a chord. By the way, when you want to sync the repetitions up to the song tempo, use the following formula: Divide 60,000 by the song tempo in BPM. The number that you come up with is equal to the delay time that you should set for quarter notes in milliseconds. Here’s an example using a song tempo of 120 BPM: 60,000⁄120 BPM = 500 ms. To figure out the numbers for other note values, divide or multiply the sum that you came up with for quarter tones by the appropriate number. Tape Loops Real dinosaurs such as the Roland Space Echo, to name possibly the most legendary among these beasts, use tape loops to generate delay signals. The signal is recorded just like on a standard tape deck and then played back by one or several play heads. The delay time is exactly the amount of time it takes for the tape to be carried from the recording head to the play head. It’s been a while since anyone has built this type of device for commercial purposes. If you scour classifieds, pawn shops and the like you might find an original device. Unless you’re a real retro freak, I wouldn’t recommend actually buying one of these brutes. Sure, tape delays sound hip, but they have serious drawbacks. Being a true mechanical device, a tape-driven delay requires a great deal of tender loving care and finding new tape loops when your old ones are ragged out is a real adventure. Analog Delays If on the evolutionary scale of delays, tape devices crawled out of the muck, analog delays began to walk upright, although certainly on shaky legs. Here an electronic circuit rather than a tape was used to record the original signal. The recorded signal was then routed to another delay unit at a variable interval called delay time. From this unit, the signal was sent to another delay unit, ad infinitum. On most devices, you could determine the number of repetitions via a knob labelled “Repeat” or “Feedback.” The manner in which these delay units were implemented inspired the colorful and truly descriptive name “bucket brigade.” Surely you’ve seen an old Western or two where somebody’s farm was torched by desperados. All the

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neighbors rush to the aid of the beleaguered family, form a human chain from the well to the house and pass buckets of water down the line to put the fire out. This is exactly how the signal is passed from unit to unit in an analog delay. To stick with the Hollywood analogy, in all the excitement, water splashes out of the bucket every time it is handed over so that— depending on the length of the line—a half or even totally empty bucket arrives at the site of the blaze. The same thing happens in analog delay— with each repetition, less of the original signal survives. Why am I explaining this in such detail? Well, insiders claim that every analog delay has its own special “sound,” and as you now know, this is not the fanciful product of the mystique-making prevalent throughout the realm of music-related electronic engineering, but the plain truth—a sideeffect of the technology used to create delay. If we take this a step further and consider that an effect is an integral component of the sound generation process, then of course its actual sound, not just the effect it produces, is significant. It might not be a bad idea for you to check out analog delays and maybe even acquire one or two of the models that sound hip to you. It may take a little effort to sound out the second-market; digital delays have pretty much displaced their analog predecessors. An exception is the “Memory Man” made by the effects wizards at the US company Electro Harmonix, which I whole-heartedly recommend to all those with a soft spot for analog delays; it simply sounds ultra-cool. Digital Delays The digital revolution, which affected everything else in the world of music, of course had a profound impact on the manner in which delay effects are generated. A digital delay is a much more “faithful” device than its analog counterpart—it doesn’t color the sound nearly as much and gives you a substantially cleaner signal. Perversely, many of these devices offer options that let you throw in some analog dirt. Here signals are artificially degraded so that you can emulate anything from a wobbly tape echo to an el-cheapo analog delay—provided you know which parameters to tweak. A huge advantage of digital delays over their analog ancestors is the ability to generate substantially longer delay times: Whereas even topnotch analog delays throw in the towel at anything over some 400 milliseconds, several seconds are standard with better digital devices.

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Plus you get a whole bunch of nifty options such as synchronizing delay time to MIDI clock. As makers have realized that they’re selling gear to musicians rather than engineers, you’ll also find that delay times are often indicated and can be set in musical intervals (quarter notes, eighth notes etc.). Then there’s so-called “Multi-Tap” circuitry, which lets you generate several different delays simultaneously and route these out via different outputs or even make them sweep through the stereoscape. Undeniably, a major disadvantage of most digital delays is the fact that they aren’t equipped with nearly enough control features to let you actually “play” the device. In this respect, analog devices are a heck of lot more fun. The bottom line: Budget constraints notwithstanding, your best bet is to stock both analog and digital delays in your arsenal of sound-shaping equipment. CD track 35: Different synthesizer sounds with delay

Chorus Chorus is presumably the most common on-board effect found on synthesizers. A chorus is really a delay with an extremely brief delay time (some 20 ms). The delay signal can be modulated variably, thus creating slight deviations in pitch. If you’ve ever heard a twelve-string guitar and noticed how much “bigger” it sounds than its six-string counterpart, then you know exactly what a chorus does. The slightly out-of-tune signals give you a fat, shimmering sound. You’ll find that for exactly this reason, chorus is often integrated into synths that are equipped with just one oscillator. By beefing up the sound of the box, the effect gave the impression that the synth was equipped with several oscillators. Although the designers’ intent may have been questionable, it led to truly legendary sounds such as the typically warm, pulsating pads of many Roland synthesizers. CD track 36: Soft pad with slowly swelling chorus

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Phaser A phaser is responsible for the type of synthesizer sounds heard on “Equinoxe” and “Oxygene” by Jean-Michel Jarre. Although he probably could have thought of more titles with “X” in them, he probably exhausted the range of possible phasing effects with these two albums. Presumably the most widely-heard phasing-type effect is the sound of the Enterprise as it whooshes off to yet another place where no man has gone before. A phaser also works with delay, albeit of a very brief nature. More significant is a process called phase shifting. The more “phase shifters”—actually the “stages” of a phaser—that the device offers, the more conspicuous its sound—here more is indeed better. When you mix the phase-shifted signal to the original signal, a specific number of frequency bands are cancelled out (the number depends on the number of stages). The more stages, the more radically the sound is bent. The “Center Frequency” knob of the phaser is used to determine which frequency bands are cancelled out. The actual phasing effect, i.e. a periodic change in tonal or timbral coloration, is created when the center frequency is modulated by an LFO, whereby the speed (Rate) as well as the modulation intensity (Depth) of this LFO are variable. Aside from the standard phasing effect that is generated by the process I just described, you can use a phaser to create totally different, substantially more unusual (in my book, more interesting) effects. For example, you can switch off the LFO to terminate automatic modulation of the center frequency (some phasers let you do this) and control the center frequency manually. Some high-end phasers and phaser modules as featured on the Clavia Nord Modular let you control the center frequency via envelopes or clock signals, which produces wacky effects with real Hall of Infamy potential. CD track 37: Poly-synth sequence a. without and b. with phaser

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Flanger Flanging is also an effect based on delay, but of substantially greater length than the delay used for phasing. The principle behind the flanger also differs from that of a phaser (the latter’s delay time is frequency-dependent, the former’s isn’t), which put simply, enables the flanger to produce considerably more spectacular sound manipulations than a phaser is able to, despite the fact that the two effects are rather similar. The big difference from a technical point of view is that you can create flanging effects using almost every digital delay. For flanging effects, you don’t need to shift the phases of signals. CD track 38: Percussive poly-synth sequence with a flanger fading in

Distortion and Overdrive Distortion and overdrive are both effects that up the grunge factor considerably. The label “Distortion” usually indicates that the effect emulates a classic transistor-based stomp box such as the Fuzzface. This type of sound has a distinct edgy, artificial sound, whereas “Overdrive” generally indicates a simulation of softer, warmer tube distortion. If you want to cook up heavy, evil-sounding stuff, both of these effects are your ticket to the “dark” side. If you just want to add some grit to a sound, these effects will give you the amount of dirt you’re after. We’ll be generous and say that the way distortion is implemented in onboard units for synthesizers is generally questionable, if not down-right ugly. You’ll find the good stuff in the guitar department rather than the keyboard corner of your local instrument shop. Try out some of the real tube preamps—some of which are amazingly affordable—that put every digital overdrive effect to shame. Having said that, the hype in the world of pickers and grinners about the new digital modeling amps has reached the level of hysteria, so we may be entering a new era in distortion. Many people consider Jimi Hendrix’s fave toy, the “Big Muff” by Electro Harmonix, the ultimate in fuzz box voodoo. Now that it has been reissued, we’ll join the club and recommend it to you. CD track 39: Step sequence with slowly increasing overdrive and filter modulations

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(Wo)Man as Modulator—“Playing” Sounds We’ve touched on this concept a number of times over the course of this book: Analog synthesizers are great for playing music in the conventional manner, i.e. notes, but you can also use them to actually “play” sounds. Here too, techno freaks and innovators in similar styles of electronica helped change the way the synthesizer is perceived and advanced it considerably on its way to becoming a truly independent instrument. Historically, synths have been regarded as the aural equivalent of a condiment, a spice to add flavor to tonally bland fare. You may remember that they were often used in less than thrilling music (does the term “prog-rock” ring any bells?). Now synths are bread-and-butter instruments, the mainstays of an entire movement. “Fair enough,” you say, “but how can I ‘play’ sounds and what tools should I use?” First of all and most importantly, you’ll need a good pair of ears. These are in any case a musician’s most important tools. By the way, these words of wisdom didn’t originate with me. I first heard my father, all his professional life one of Germany’s leading figures in the world of classical music, voice this opinion. I’ve passed them on to you to illustrate that the importance of training yourself to hear what’s going on is essential in every style and genre of music. Always listen closely and focus on what’s going on. Develop a kind of internal taste-o-meter and evaluate what’s happening in terms of sound: Is it thrilling or chilling? If it’s boring, change it. What exactly you change is up to you. There are no rules, just make it exciting. Here’s nevertheless a tip that I’ve found helpful: You don’t always have to add something to make for a more exciting sound. Sometimes your best bet is to remove an element. For example, if you have a really heavy-duty bass sound, tweak it so that it loses all its “oomph.” Your audience will notice immediately and try to anticipate when you will pump it up again.

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Analog synthesizers feature a host of tools that you can wield in the traditional sense of the word—the many dedicated control features for all the parameters that you have available. Try anything out of the ordinary like changing the timbre of the sound to the groove of the music, generate rhythms via volume modulations, sweep sounds through the sonic landscape at any pace you see fit, play with the attack, decay and release times of envelopes. There are only two things that you should keep in mind when you’re experimenting: Be sure you have a general idea of what you are attempting to prevent disasters of different orders (sudden absolute silence, hopelessly distorted recordings, shot speakers), and—I know I’m repeating myself— listen, listen, listen. Here are a few practical tips to get you started: ❖ String pads, bass sounds, rhythmic chord sequences and the like can be “revved up” and “throttled” during the course of a track by varying the cutoff frequency, resonance, volume, pitch, panning and any combination of these parameters, all which will give you a more dynamic sound. Whether you—spurred by spontaneous inspiration—do this manually or prefer to program the whole thing in a sequencer is entirely up to you. ❖ More and more synthesizers give the option of controlling two or more parameters simultaneously via a single other parameter. Often you can define to which extent each of the involved parameters is manipulated. The bandwidth of potential effects encompasses everything from bending sounds more or less radically to seamless cross-fades between two totally different sounds. Keep in mind that you can record these manipulations to your sequencer when ever you choose to. ❖ Program a sequence featuring a “score” of sounds rather than notes. ❖ “Play” the effects that are part of a sound. For instance, blend in delay (think Jamaican dub) or fiddle with the dry/wet mix. Change the delay time manually, which creates bizarre pitch glitches, especially when you’re using analog delays. (Warning: Particularly when you cut the delay time drastically, be sure to keep one hand either on the Volume or Repeat knob, because the delay signal tends to suddenly acquire a life of its own and its level goes overboard.)

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Again, these are just a few tips that may inspire you to bigger and better things. The possibilities for “playing” sounds are as limitless as your imagination. Your best bet is to just get started; in all likelihood you’ll never stop.

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Appendix Contents of the Audio CD In this table, you’ll find a survey of the audio examples on the CD. For every example, we indicated the synthesizer we used to produce the sound bite and the page on which the subject related to it is discussed. Track

Description

Synthesizer

01

Typical sounds and phrases of analog synthesizers: Moog Lead, Moog Sequenzer Bass, Modular Arpeggio, OB Dark Poly, OB Rock Poly, Modular SynthBrass, OB GlideDrone, Moog MegaBass, OB Warm Pad

Multimoog, Oberheim OB-Xa, Clavia Nord Modular

20

02

Sequence with sawtooth waveform

Nord Modular

40

03

Sequence with square waveform

Nord Modular

41

04

Sequence with pulse waveform, the pulsewidth changes during the course of the sequence

Nord Modular

42

05

Sequence with triangle waveform

Nord Modular

42

06

a. Sequence with sine waveform, b. sine subbass, c. sine laser

Nord Modular

43

07

a. Seamless crossfades between white and pink noise b. Analog drum kit—all drums based on noise

Nord Modular/ EQ/FX

43

08

Crossfade: One oscillator alone  increasingly detuned

Moog Multimoog

45

09

a. One oscillator alone, b. two oscillators tuned a fifth apart, c. two oscillators an octave apart

Moog Multimoog

45

10

Sequence with synchronized oscillators, the slave oscillator is detuned.

Moog Multimoog

46

11

Diverse examples of ring modulation

Nord Modular

46

two oscillators 

Page

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Appendix Track

Description

Synthesizer

12

Amplitude modulation—the modulator is transposed in semitone steps into the range of audible frequencies.

Nord Modular

47

13

Frequency modulation: a. Ratio 1:1, the modulator is slowly turned up, b. constant level, the modulator frequency is increased in whole-number intervals (1:1, 1:2, 1:3…)

Nord Modular

47

14

Filter sweep envelope with notes played at staggered intervals

Oberheim OB-Xa

50

15

Sequencer bass where the resonance is slowly turned up to the point of self-oscillation

Nord Modular

50

16

Low pass sweep from top to bottom, high resonance

Nord Modular

52

17

High pass sweep

Nord Modular

52

18

Band pass sweep

Nord Modular

53

19

Band reject sweep

Nord Modular

54

20

a. Poly-synth phrase without filter; b. with 12-dB filter, percussive envelope; c. with 24-dB filter, percussive envelope

OB-Xa

57

21

Amplitude envelopes: a. organ, b. piano, c. backwards, d. brass

Nord Modular

65

22

Pitch envelope: a. percussive, b. trumpet, c. synth, d. synth brass

Nord Modular

66

23

LFO modulations—simultaneously influencing the oscillator, cutoff and pan—with varying rate: a. sine, b. triangle, c. saw up, d. saw down, e. square, f. random

Nord Modular

71

24

Vibrato—here and in the following LFO examples, the LFO rate is controlled via an envelope.

Nord Modular

76

25

Tremolo

Nord Modular

76

26

PWM

Nord Modular

76

27

Trill

Nord Modular

76

28

Auto-panning with different LFO waveforms

Nord Modular

77

29

a. LFO to filter cutoff b. square LFO to VCA, c. descending sawtooth to VCF and VCA

Nord Modular

77

30

a. Portamento, b. Fingered portamento (Legato portamento effect)

Nord Modular

84

116

Page

Pocket Compendium of Analog Sound Synthesis Track

Description

Synthesizer

Page

31

Envelope Follower: The amplitude of the drum loop signal controls the cutoff frequency of the filter through which the drum loop is being sent (auto-wah).

Nord Modular

96

32

Sample&hold: near random pitch variations

Nord Modular

98

33

Vocoder (carrier: poly synth), speech signals: a. drum loop, b. human speech

Nord Modular

101

34

Step sequencer with a tonal modulation

Nord Modular

105

35

Different synthesizer sounds with delay

Diverse

109

36

Soft pad with slowly swelling chorus

Nord Modular

109

37

Poly-synth sequence a. without and b. with phaser

Nord Modular

110

38

Percussive poly-synth sequence with a flanger fading in

Nord Modular

111

39

Step sequence with slowly increasing overdrive and filter modulations

Nord Modular

111

Pocket Compendium of Analog Sound Synthesis ADSR

Acronym for Attack, Decay, Sustain, Release. This is the most common type of envelope used in analog synthesizers.

Aftertouch

The ability of an instrument to respond to pressure applied to a key on the keyboard after the key is initially pressed.

Amplifier

In this context, the component or module that boosts the level of a signal.

Analog

In this context, “analog” designates electronic equipment in which the signal corresponds to a physical change brought about by circuits and discrete components such as capacitors, resistors, transistors etc.

Analog Delay

Analog device used to replicate a signal a variable amount of time after it receives the original signal.

Analog Sequencer

 Step sequencer.

Astrogirl

Noise created by different components combined in a module. Often turned up to painful levels in Cologne’s Liquid Sky Cologne Club.

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Appendix Attack Time

The first parameter of an envelope generator which determines the rate or time it will take for the event to reach the highest level before starting to decay.

Band Reject Filter

Same as band stop filter

Band Pass Filter

A filter which allows only a selected band of frequencies to pass while rejecting all other frequencies above and below the cutoff point. The frequency located dead-center of the frequency band that is allowed to pass is called the center frequency.

Band Stop

Filter consisting of a low pass and high pass filter set up in series. It cuts a frequency band out the of the signal.

BPM

Short for Beats Per Minute. Used to indicate the tempo of songs.

Clock

A steady pulse used to control repetitive events and for synchronization. In vintage synths, it is generated exclusively via control voltage; modern devices run on MIDI clock, a digital clock signal.

Corner Frequency

Another term for cutoff frequency

Control Voltage Electrical charge used to manipulate synthesis parameters. Practically all “true analog” synthesizers work with control voltages, “virtual analog,” which in reality are digital synthesizers, are controlled via digital information. Controller

General term for the control features of a synthesizer

Cutoff Frequency

The frequency at which a filter will start filtering signals present at its input.

CV

Short for Control Voltage

DCA

Short for Digital Controlled Amplifier, an amplifier which is controlled by digital information rather than—like a VCA—control voltages.

DCF

Short for Digital Controlled Filter, a filter which is controlled by digital information rather than—like a VCF—control voltages.

DCO

Short for Digital Controlled Oscillator, an oscillator which is controlled by digital information rather than—like a VCO—control voltages.

Decay Time

In an envelope, the amount of time it takes for a signal to fall from peak level to sustain level.

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Pocket Compendium of Analog Sound Synthesis Delay

A variable parameter giving the ability to start an event only after a predetermined amount of time. The devices that are used to generate delay signals are also called delays.

Digital

Equipment that uses quantities represented as binary numbers. In a digital synthesizer, every aspect of sound generation is handled as a numeric calculation. This digital information is not audible, so it must be converted into analog form.

Digital Delay

A device that uses digital quantities and components to calculate delayed output signals.

Distortion

The sound of an overdriven signal

Envelope

An envelope is used to modulate a sound-shaping component within a given time frame so that the sound is changed in some manner.

Envelope Generator

A circuit in synthesizer, usually triggered by pressing a key on a keyboard, that generates a changing voltage with respect to time.

Envelope Shaper

Another term for envelope generator

Envelope Follower

A synthesizer component that samples the input signal and generates control voltage based on the amplitude of the signal.

Filter

A synthesizer component that changes the intensity of and relationship between the fundamental tone and overtones and thus the timbre of a sound.

Fixed filter

In an analog synthesizer, this is a filter with a cutoff frequency that cannot be varied via control voltages.

Formant filter

Another term for fixed filter

Frequency

The number of cycles per unit of time. It is indicated in Hertz (Hz); 1 Hz = 1 cycle/second.

Gate

A pulse signal that has two conditions, “active” and “inactive.” Usually used to control envelopes: When a gate is activated, an envelope is started, when the gate is deactivated, the envelope goes into its release phase.

Glide

Another term for portamento

Glissando

A rapid movement through a series of consecutive half-tone steps from one note to another

Hertz

Unit of measure for frequencies; 1 Hertz = 1 cycle/second

High Pass Filter A filter that allows only frequencies higher than its cutoff to pass.

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Appendix Hz

Short for Hertz

Infrasonic

Sound with a frequency below 16 Hz and thus beyond the range of human hearing

Key Follow

Control information derived from the position of key played on a keyboard. This feature was originally designed to simulate certain properties of acoustic instruments. For example, this information can be used to manipulate the amplifier envelope so that as the pitch increases, the decay time of notes decreases to emulate the response of a piano.

Key Tracking

Another term for key follow

Keyboard

In this context, the term for the piano keyboard used to enter note data to a synthesizer.

Keyboard Tracking

Another term for key follow

kHz

Short for kilohertz; 1 kHz = 1,000 Hz

Level

The degree, strength, or loudness of sound

LFO

Short for Low Frequency Oscillator

Low Frequency Oscillator

An oscillator used for modulation with a frequency below the audible range (usually 0.1 to 100 Hz). Primarily used as a modulation source to generate cyclic changes (vibrato, tremolo etc.).

Low Pass Filter

A filter whose frequency response remains flat up to a certain frequency, then rolls off (attenuates signals appearing at its input) above this point.

MIDI

Short for Musical Instrument Digital Interface. MIDI enables synthesizers, sequencers, computers, rhythm machines, etc. to be interconnected through a standard interface for the purpose of exchanging information.

MIDI Clock

 Clock

MIDI Sequencer

Hard- or software for recording and playing back MIDI information

Modular Synthesizer

Synthesizer consisting of modules that are not connected permanently to one another, but can be interconnected freely.

Modular System

Another term for modular synthesizer

Modulation

In acoustics: Variation in the amplitude, frequency, or phase of a wave in accordance with some signal, in a synthesizer: The process of one synthesizer parameter influencing another

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Pocket Compendium of Analog Sound Synthesis Modulation Wheel

Wheel-shaped controller for realtime manipulation of synthesizer parameters. Often permanently assigned to vibrato.

Module

In an analog synthesizer, a component or assembly with a specific function

Monophonic

In this context, a single voice

Noise

In this context, a random signal comprised of an equal portion of all frequencies at the same volume

Noise Generator

Synthesizer component used to create noise.

Notch Filter

A special type of band stop with a very narrow bandwidth and a steep slope. Used to filter out specific undesirable frequencies.

Oscillator

Synthesizer component that generates oscillations.

Overdrive

Distortion effect that simulates an overloaded tube amp.

Overtone

Every sound consists of a fundamental tone that determines its pitch and overtones that determine its timbre. Overtones have a frequency of vibration that is an exact multiple of the frequency of the fundamental. Also called “harmonics.”

Patch

In modular systems, this is a circuit combining synthesizers created by connecting several modules. The term is often used as a synonym for storable programmed sounds in synths with a memory.

Patch Cord

Cord used to connect synthesizer components in modular systems

Pink Noise

Signal created by damping the high frequencies in white noise

Pitch

The element of a tone or sound determined by the frequency of vibration

Pitch Bending

Changing pitch seamlessly

Pitch Wheel

Wheel-shaped controller for realtime pitch bending

Polyphonic

The property of producing more than one tone at time; multi-voice

Portamento

A continuous automatic gliding from one note to another, sounding intervening tones

PPQ

Short for Pulses Per Quarternote. Usually used in connection with clock to indicate its resolution.

Preset

On a synthesizer, a fixed programmed sound

Pulse Wave

Square wave with a variable relationship between pulse and rest

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Appendix Pulse Width

Describes the ratio of pulse and rest in a pulse wave. Pulse width is indicated percentages. At a pulse width of 10 %, the ratio between the pulse and the rest is 1:9.

Pulse Width Modulation

Changing the pulse width of a pulse wave via a modulation source such as an LFO

PWM

Short for Pulse Width modulation

Random

Lacking aim or method

Square Wave

Square-shaped wave with pulse and rest of the exact same length. Contains exclusively odd-numbered overtones.

Rectangle

Another term for square wave

Release Time

Length of the phase of an ADSR envelope that is triggered when the gate that started the envelope is deactivated. Usually this is executed by releasing a key. If the envelope is assigned to the VCA of the synthesizer, then the release time is the amount of time it takes for the tone to fade out after the key is released.

Resonance

Parameter for boosting the frequency band surrounding the cutoff frequency of a filter

Ribbon Controller

Strip-shaped controller once made of wire mesh or velvet, today made of plastic

Ring Modulator Synthesizer component that processes two input signals so that the sum and difference of the two signals is routed to its output. In analog synthesizers, it used to generate odd-numbered overtones such as bells, gongs etc. Sample

A part, piece, or item taken or shown as representative of a whole thing

Sample&Hold

Synthesizer component that takes samples of voltages at given intervals and holds these. These voltages are routed to the module’s output and send to other synthesizer components for further processing. If you select noise as the input signal, then the sample & hold module serves as a “random generator.”

Saw

Short for sawtooth

Sawtooth Wave

Waveform containing all overtones

Sequencer

A device that steps through a series of signals or data called a sequence that can be controlled via synthesizers.

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Pocket Compendium of Analog Sound Synthesis Slope

Indicates how steeply the curve of a filter drops off after its cutoff frequency. In the audio world, which of course synthesizers are a part of, slope is indicated in dB/octave values.

Step Sequencer

Sequencer featuring a certain number of steps that can be repeated periodically. In the past this was only type of sequencer available. All of these were analog in design, which is why they are often referred to as “analog sequencers.”

Sustain Level

Level at which an ADSR envelope remains after it has run through the decay phase until the gate controlling it is deactivated. When the envelope is controlled via the keyboard, then this is the moment at which a key is released.

Time

In this context, interchangeable with rate

Track

The term is used both to indicate an individual component of a multitrack recording as well as an entire song.

Triangle

Waveform containing all overtones, although these are severely dampened. Thus its sound is closer to that of sine than a sawtooth wave.

Voltage Control A method of controlling processes via an electrical charge Waveform

The characteristic curve of an oscillation cycle. The names of most waveforms were inspired by what their shape looks like on an oscilloscope (e.g. triangle, square etc.).

Waveshape

Another term for waveform

Wheel

Wheel-shaped controller on a synthesizer

White Noise

A signal that contains all frequencies at equal volumes and thus does not have definite pitch. The sound is best described as the rush of a waterfall.

123

Index Numbers

C

1-Volt/Octave specification 81

Channel Aftertouch 86 Chorus 76, 109 Clock 72, 118 Compact Synthesizers 26 Control Voltage 118 Controller 118 Ribbon ~ 122 Corner Frequency 118 Cutoff 50 ~ Frequency 118 CV 118

A ADSR 62, 117 Aftertouch 34, 86, 117 AM 47 Amplifier 59, 117 Amplitude ~ Envelope 65 ~ Modulation 47 Analog 117 Analog Delay 107, 117 Analog Sequencer 117 Analog Synthesizers 19 Analog Virtual ~ 28 Astrogirl 117 Attack 62 ~ Time 118 Auto Panning 77

B Band Pass 53 ~ Filter 118 Band Reject Filter 118 Band Stop 54, 118 BPF 53 BPM 118 Breath Controller 94 Buchla Don ~ 18

D DCA 60, 118 DCF 49, 118 DCO 39, 118 Decay 62 ~ Time 118 Delay 106, 119 Analog ~ 107 Digital ~ 108 LFO ~ 73 Digital 119 Digital Delay 108, 119 Distortion 111, 119 DX Synthesizer 47 Dynamophone 11

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Index

E Effects Types 105 Envelope 33, 61, 119 ~ Follower 96, 119 ~ Generator 119 ~ Shaper 119 ADSR ~ 62 Filter ~ 65 Modulating via ~s 67 Pitch ~ 66 Volume ~ 65

F Filter 32, 49, 119 ~ Envelope 65 ~ Sweep 50 Band Pass ~ 118 Cutoff 50 Fixed ~ 119 Formant ~ 119 High Pass ~ 119 Low Pass ~ 120 Notch ~ 121 Resonance 50 Timbre 57 Fixed Filter 119 ~ Bank 98 Flanger 111 FM 47 Foot Switch 90 Footage 44 Formant filter 98, 119 Frequency 44, 119 ~ Modulation 47 Corner ~ 118 Cutoff ~ 118

Glissando 119

H Hammond 16 Hard-wired Synthesizers 26 High Pass 52 ~ Filter 119 HPF 52

I Infrasonic 120 Intervals 45

J Joystick 93

K Key Aftertouch 86 Key Follow 84, 120 Key Tracking 84, 120 Keyboard 79, 120 ~ Tracking 120

L Level 120 Lever 92 LFO 33, 69, 120 ~ Delay 73 ~ Fade 73 ~ Rate 72 Low Frequency Oscillator 69, 120 Low Pass 52 ~ Filter 120 LPF 52

M G Gate 35, 82, 119 Glide 84, 119

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Matrix Patchboard 23 MIDI 120 ~ Clock 120

Index ~ Sequencer 120 Minimoog 26 Mixturtrautonium 17 Modular Synthesizer 23, 120 Modular System 120 Modulating via envelopes 67 Modulation 120 ~ Generator 69 ~ Wheel 89, 121 Module 121 Monophonic 83, 121 ~ Aftertouch 86 Moog ~, Robert 18 Minimoog 26 Multimoog 86 Multimoog 86 Multi-Trigger 82

Pink Noise 43, 121 Pitch 44, 121 ~ Bending 121 ~ Control 81 ~ Envelope 66 ~ Wheel 121 Pitch-to-Voltage Converter 97 Polyphonic 83, 121 ~ Aftertouch 86 Portamento 84, 121 PPQ 121 Preset 121 Pulse ~ Wave 41, 121 ~ Width 122 ~ Width Modulation 42, 122 PWM 42, 122

R N Noise 43, 121 ~ Generator 121 Pink ~ 121 White ~ 123 Notch Filter 121

O Ondes Martenot 14 Oscillator 32, 39, 121 ~ as a Modulator 95 ~ Sync 46 Overdrive 111, 121 Overtone 121

P Patch 121 ~ Cord 121 Pedals 90 Phaser 110 Piano Keyboard 79

Random 122 ~ Waveform 71 Rectangle 122 Release 62 ~ Time 122 ~ Velocity 87 Resonance 50, 122 Retrigger 82 Ribbon 90 ~ Controller 122 Ring 46 ~ Modulation 46 ~ Modulator 122

S Sala Oskar ~ 17 Sample 122 Sample & Hold 97, 122 Saw 122 Saw down 70 Saw up 70

127

Index Sawtooth 40 ~ Wave 122 Sequencer 122 Analog ~ 117 Step ~ 101, 123 Sine 42 Single Trigger 82 Slope 55, 123 Sound 31 Sound Synthesis 31 Speed 72 Spherophone 13 Square 41 ~ Wave 122 Step Sequencer 101, 123 Suboscillator 45 Sustain 62 ~ Level 123 Sync 46 Synthesizer 11 ~ as an Effects Device 96 Analog ~ 19 DX ~ 47 Hard-wired ~ 26 History 11 Modular ~ 23, 120 Predecessors of the ~ 18

T Tape Loops 107 Theremin 12 Time 123 Track 123 Trautonium 15 Tremolo 76 Triangle 42, 123 Trigger 34, 82 Multi-~ 82 Single ~ 82 Trill 76 Types of Effects 105

128

U Unisono Mode 84

V VCA 59 VCF 49 VCO 39 Velocity 34, 85 Release ~ 87 Vibrato 75 Virtual Analog 28 Vocoder 99 Voltage Control 123

W Wave Sawtooth ~ 122 Square ~ 122 Waveform 39, 123 Waveshape 123 Wheel 89, 123 White Noise 43, 123

X X/Y Pad 93