modularworlds2 1 0 werbemuster - synmag · jean-michel jarre needs to be credited as one of the...

A Guide To Modular WorldsUse synthesizers for more personal creativity

Rolf-Dieter Lieb • Ulf Kaiser

Lieb Kaiser

Modular Worlds

DON‘T PANIC! � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 8

Work in progress � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9

Introduction 11A Brief History of electronic Synthesizers � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 12

Modular, Semi-Modular, MIDI-Modular - What is it all about ? � � � � � � � � � � � � � � � � � � � � � 20

East Coast, West Coast - Synthesizer Concepts � � � � � � � � � � � � � � � � � � � � � � � � � � � 26

Racks & Jacks - Sizes of Modular Synthesizers � � � � � � � � � � � � � � � � � � � � � � � � � � � � 32

About Electrics - Most important Facts condensed � � � � � � � � � � � � � � � � � � � � � � � � � � 42

Power is nothing without Control ! 51Gates, Clocks and Triggers - The Power of On/Off ! � � � � � � � � � � � � � � � � � � � � � � � � � � 52

Start, Stop & Tempo - Gate & Clock Manipulation � � � � � � � � � � � � � � � � � � � � � � � � � � � 58

Slew up and down - The Making of Envelopes � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 62

Undulating Movements - Periodic Control with LFO & Loops � � � � � � � � � � � � � � � � � � � � � 68

Add, Multiply & Subtract - Signal-fusion with VCAs & Mixers � � � � � � � � � � � � � � � � � � � � � 76

And Action... ! 83User Interfaces - How to interact with Electronics � � � � � � � � � � � � � � � � � � � � � � � � � � 84

Technical Interfaces - MIDI, USB, CV, Gate and more linked together � � � � � � � � � � � � � � � � � 90

User’s Helpers - Arpeggiators, Quantizers & S&H � � � � � � � � � � � � � � � � � � � � � � � � � � � 98

User’s Companions - Sequencers of various types and applications � � � � � � � � � � � � � � � � 104

Make them sing ! 111Triangle, Sawtooth & Square - Classical Oscillator Concepts � � � � � � � � � � � � � � � � � � � � 112

What’s all that noise? - About Colors & Origins � � � � � � � � � � � � � � � � � � � � � � � � � � � 120

Two is more than one - Audio controls Audio Part I (AM, RM & Sync) � � � � � � � � � � � � � � � � � 126

I am MasterYou are Slave - Audio controls Audio Part II (FM, PD & Waveshaping) � � � � � � � � � � 134

Wavetables & Sampler - Digital Audio Sources I � � � � � � � � � � � � � � � � � � � � � � � � � � 142

Physical Modeling & Granular - Digital Audio Sources II � � � � � � � � � � � � � � � � � � � � � � � 150

Less is More I - Classic Filters and their application � � � � � � � � � � � � � � � � � � � � � � � � 156

Less is More II - Filter Resonance & Self-Oscillation � � � � � � � � � � � � � � � � � � � � � � � � 162

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Make them cry ! 169From Overdrive to Distortion - Special Amplification � � � � � � � � � � � � � � � � � � � � � � � � 170

Dynamic control by nonlinear amplification � � � � � � � � � � � � � � � � � � � � � � � � � � � � 176

Come and go - Delay & Reverb Effects � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 180

Floating & Squeezing - Chorus, Flanger, Phaser & alike � � � � � � � � � � � � � � � � � � � � � � � 186

Fun or Harm ? - Bit Crushing, Sample Rate Reductions & alike � � � � � � � � � � � � � � � � � � � � 194

Make them dance ! 201Tip Top Tap - Rhythm Generation � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 202

Boom, Bam, Splash - Rhythm Sound Sources � � � � � � � � � � � � � � � � � � � � � � � � � � � � 210

Many Functions in One - Voice-Modules � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 216

Many is More - Polyphonic Modules � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 220

Virtual in its own Right ! 227Do I look like it ? - Software Synthesizer & Modulars � � � � � � � � � � � � � � � � � � � � � � � � 228

Everything in Recall - DAW-Control of Modulars � � � � � � � � � � � � � � � � � � � � � � � � � � � 242

Back & Forth - Hybrid Concepts � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 248

Now I want more ! 253Where to get Information ? - Print & Online Magazines � � � � � � � � � � � � � � � � � � � � � � � 254

Where to get Advice ? - Websites, Forums & Communities � � � � � � � � � � � � � � � � � � � � � 258

Where to buy Stuff ? - Shops, Online & more � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 262

Make your own Stuff ? - Live & DIY � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 270

Where to meet ? - Tradeshows & Meetings � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 280

For Readers - Some Literature � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 286

Index � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 290

Picture Credits � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 298

The Team behind this book � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 299preliminar

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Part IV

Part V

Part VI

Part VII

Statements of

Manufacturers4ms Company � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 178

1010music � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 192

ACL � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 160

AJHSynth � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 124

Arturia � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 214

Cwejman � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 66

Doepfer � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 38

Endorphin�es � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 30

Erica Synth � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 132

Expert Sleepers � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 96

Five 12 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 102

GRP Synthesizers � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 118

Jomox � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 208

Moog Music � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 48

Mutable Instruments � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 166

Nonlinear Labs � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 234

Radikal Technologies � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 218

Rossum Electro-Music � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 148

SchneidersLaden / Alex 4 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 266

Sequential � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 88

Superbooth � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 284

Toontrack � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 224

u-he � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 56

Verbos Electronics � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 184

Vermona � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 198

WMD � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 174

Statements of

ArtistsBernd Kistenmacher � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 250

Boris Blank � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 18

Charlie Clouser � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 72

Christian Halten� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 256

Daniel Miller � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 24

Jean-Michel Jarre � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 60

Johannes Schmoelling� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 154

Jörg Hüttner� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 246

Michael Lehmann Boddicker� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 260

Michael Menze � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 274

Reinhold Heil � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 80

Richard Devine � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 140

Vince Clarke� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 108

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This book is an introduction to the highly complex world of electronic circuitry used for sound production as known from instruments widely called synthesizers. It is therefore not free of tons of technical terms and technical descriptions. As the title points out, this book focuses in particular on the type of synthesizer circuitry known and available as modules. This means that certain function blocks are built into a unit, which can then be interlinked to other modules by means of simple cables, allowing for countless new combinations of such modules.

In other words, we are dealing with a nerdy topic that can well consume those who love it!

In a market with many small manufacturers, new modules get announced or available nearly every week. Online platforms already list more than 1000 different products in the most popular Eurorack format. It may not be useful to know all of these! In fact, most users will certainly not be willing to spend too much money but rather look for a suitable setup for their specific needs. For a better understanding which module might be useful for ones purposes, this book tries to introduce the most important facts and principles in a systematic approach. Topics like possible DIY with modules, software alternatives and DAW-integration are included in the same way as classical and modern standards of the modular world.

However we believe that this topic and the knowledge behind it can bring good ideas to practical and experimental musicians and to all kinds of electronic music. One will not need to dig into every detail in order to make (huge) profit for everyday music creation and moreover for a better understanding of how today‘s electronic musical instruments work and which possibilities they might offer.

We have added interviews with many interesting developers and musicians from the world of music production in order to underline the thinking and lifestyle that developed from this community and which influences other movements of modern music produc-tion as well as young peoples‘ lifestyles around the world.

So have a try and let yourself be guided to this formerly unknown galaxy of modular and non-modular synthesizers, its technology, its products, its philosophy, its tech speak and its people! We hope to have explained the tech issues in a way everybody can understand and wish you a good journey as a reader as well as a creator of music and emotions, which is in the end, what we all do this for!

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DON‘T PANIC! A Welcome by Rolf-Dieter Lieb

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Modular sound today is a lot more than it ever was. We are in the middle of the renais-sance of modular synthesizer systems where patchable components are developed in more places than ever. What was thought to be outdated has returned – like fashion styles, musical genres or other trends. The obvious question is why?

Being different is a strong driving force. Engineers search the unspotted and so does the next generation of artists. Whether you have never played a modular synthesizer or that experience has disappeared in old memories, it is still magic!

But there are further reasons …

The driving force behind the first synthesizers were engineers wanting to travel uncharted territory. Music and instruments already had a long history in the exploration of sound. Electronic components empowered these inventors to create an immense bandwidth of sounds by adjusting the basic parameters of any sonic event: volume, pitch, duration, timbre and their course over time.

60 years later, synthesizers have massively shaped the sound of music. They became ex-tensions to existing genres, brought up new musical styles and entered the digital world, reducing their cost from unaffordable to partially free.

Still, the search for new sounds is an important factor of any synthesizer. On the other hand, new products are also measured by their capabilities to reproduce “classic” electro-nic sounds. And both aspects combined lead to larger interest.

Furthermore, we live in a world being dominated by computers. Musical instruments however want to be touched! Compare a Minimoog to its virtual counterparts: Our ears may be satisfied, but our hands often are not.

Doubtlessly, the virtualization of the studio brought us big benefits. But since we spend a good portion of the day with a computer, we may not want to continue this when being creative. Also, software – as good as it can be – has the drawback that it can be copied endlessly. We all use Word to type and maybe Pro Tools to craft our mixes. However, as an artist we appreciate individuality. And here we are …

Today‘s modular scene is a community of developers, dealers and users that embrace the development of countless new sound-shaping components. Combine a few (often limi-ted) modules and you will end up with a unique instrument, mostly without memory locations. Does it get more individual?

Even better: All aspects being mentioned can be combined. Current modular systems consist of modules of multiple manufacturers, offer classic, advanced analogue circuits, digital source code and even exist in virtual form. They can be used standalone or in combination with digital workstations. Great for studio and stage, highly usable to create music, sounds, FX, installations and a lot more. In short: Modular systems are no thing of the past, but playgrounds of creativity that continue to develop in countless directions.

Enjoy reading!

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Work in progress An Introduction by Ulf Kaiser

Jean-Michel Jarre needs to be credited as one of the most influential musicians to bring electronic sounds into our music-listening-world. Jarre studied piano and com-position. He was educated in the Groupe de Recherches Musicales by Pierre Schaef-fer, founder of the Musique Concrète movement, and Pierre Henry.

His breakthrough was his debut album Oxygène, released in 1976 and recorded on an 8-track tape-machine in his private appartment. It started his ongoing worldwide, 50 years spanning, career with several album productions, several collaborations and live-events of monumental size that even made it into the Guiness Book of Records.

Lyon-born Jarre owns a studio in Paris with a large collection of synthesizers. Among his favorites are the EMS VCS3, the ARP 2600, the Fairlight CMI and the Elka Synthex. However, Jarre has always followed and embraced the latest innovations in electronic instrument development – from sampling to plug-ins to Eurorack.

Title: Jean-Michel and his ARP 2500 © Photo by Herve Lassince

Jean-Michel Jarre

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What‘s your relationship to modular systems?

I started with modular systems. When electronic music was in its beginning, we, at GRM (Groupe de Recherches Musicales) or Karl-Heinz Stockhausen took pieces of radio mea-surement equipment to create such a system. This was before Moog designed a modular system as a dedicated instrument. Anyway, those big modular synthesizers were really expensive and it was really difficult to purchase or even use one back then. For Oxygène I used an EMS VCS3 and AKS, a Moog modular and the ARP 2600 among other sound gene-rators like the Mellotron or the Eminent 310 U.

What do you think about the Eurorack development?

I own and use Eurorack modules. One of the aspects I love is: When plug-ins emerged on the market, they were often imitating hardware in a virtual format. Now, some Eurorack modules create plug-ins in a hardware format. That‘s great because suddenly a new gene-ration of musicians can now find out what electronic music is all about – it is a very tactile and sensitive approach to sounds. Even though I love plug-ins, we are analog animals after all. And the machine in front of you will have a heavy influence on what you do.

What I also like about Eurorack is the large number of manufacturers! Instead of having one guy, that designed his modular system in the old days, you can now freely combine oscillators, filters and modulators of different brands to your personal preference.

I am a fan of the Latvian company Erica Synths. They have a double vision of creating cra-zy sounds, for example by using valves, but also a high quality approach. Plus, they have a great look. People often forget the importance of aesthetics in electronic music. Beau-ty and aesthetics will also help to develop expression of your own feelings and emotions. This is no different to a nice electric guitar. Other brands that I really like are Intellijel and Mutable Instruments.

Could you compare the Eurorack to your old modular systems?

I believe, we cannot or should not compare an EMS VCS3, ARP 2500 or a big Moog system to a Eurorack system. It is entirely depending on what you want to do. At the same time I think, we are still at the dawn of Eurorack. I often hear drones from these instruments, which is great. However, there is so much more you can do with Euorack modules. I hope this is just the beginning of a longer story…

Do you combine your modular system with your digital production environ-ment?

Yes, of course. For example, I have done this a lot on my current album Equinoxe Infinity. I have used my Moog modular and Eurorack modules and combined these with granular sounds of my Tasty Chips GR-1. Partly, I will control the modules from my computer being used as a sequencer. On the other hand, my main sequencer is still the custom-made Digi-Sequencer which was created by Michel Geiss and Jean-Claude Dubois.

www.jeanmicheljarre.com

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Undulating Movements Periodic Control with LFO & Loops

Title: Roland System 100

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Undulating Movements – Periodic Control with LFO & Loops

We have introduced the key element of a Control Voltage (CV) in the previous chapter. Gate signals trigger the envelope generation to modulate parameters of different mo-dules in a modular synthesizer system. But what is available for continuous modulation of parameters?

The standard type of continuous modulation CV is the output of a Low Frequency Oscil-lator (LFO). Oscillation means that the signal is a continuous repetition of periodic chan-ges of the signal over time. This is like the swinging of a pendulum or children’s swing, which is equal to a sine curve. The describing parameters of such a periodic signal are usually given as

• Waveform, e.g. a sine wave

• Frequency, which is 1 divided by the duration time of one period or cycle of the wave-form

• Amplitude, which is the difference between maximum and minimum voltage level of the cycle, e.g. +/- 5 V creates an amplitude of 10 V peak to peak,

and sometimes…

• Delay, which starts the oscillation with a delay after the trigger signal is received

• Phase, which is only relevant for the comparison of several waves of similar frequency.

Nearly every LFO Module creates its signal with the highest possible amplitude, as the intensity of a modulation is not adjusted on the LFO but on the receiving module, as we will see in the next chapter. However the signal may be bi-polar, like from -5V to +5V or uni-polar, if it is only ranging from 0V to +5V.

The most popular Waveforms are shown in the graph below for 2 cycles each (first green, second blue). The Sine Wave mentioned above and shown on top of the graph is the most simple one and created by a natural circular movement. If the periodic cycle alternates between minimum and maximum level with a linear rise and fall of equal slew rate, a Triangle Wave is created. (Fig. 1)

Fig. 1: Classic Waveforms and their naming

period 1 period 2

time0V

voltageSine Wave

time0V

voltage Rectangle orSquare Wave

time0V

voltage

Triangle Wave

time0V

voltage Sawtooth orRamp Wave

period 1 period 2

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If one amplifies a Triangle Wave with maximum amplification all positive voltages go to max level and all negative voltages go to min level (or max. negative level) with only very short and steep ramps in between. The result of a symmetric triangle (same size in the positive and negative levels) is then a symmetric rectangular waveform, which is usually called a Square Wave.

If the positive and negative parts are not of equal size, e.g. because the triangle wave was shifted with its mean level above or below the zero level, the resulting rectangular wave-form will have different lengths in its positive and negative part. This kind of waveform is known as a Pulse Wave. A Square Wave is a special Pulse Wave with 50% length of the positive pulse. We already discussed that kind of periodic pulse in chapter 7 on clock si-gnals. The gate length was then the equivalent of what is here called the Pulse Width. As we will see in chapter 15 on classic Audio Oscillators, the modulation of the Pulse Width is a common parameter of rectangular wave forms as well. (Fig. 2)

The last classic waveform shown above is known as Ramp or Sawtooth Wave. Mostly triggered as a start the maximum level is jumped to and a decreasing ramp follows to arrive at the negative max level (mathematically speaking at the min level). As this form is similar to the teeth of a saw for cutting wood, it is called Sawtooth Wave. If the jump is down to min level and the ramp rises to max. level this inverse waveform to the Saw-tooth Wave is sometimes called Ramp Wave, negative Sawtooth or Rising Sawtooth. In the graph this wave is shown in yellow.

Of course, the LFO waveforms are expected to continue without interruption (and not only in few cycles as shown in the graphs) and are usually created with max and min level to get the biggest possible amplitude. This is because it is much easier to reduce the CV amplitude than to amplify it, as we will see in the next chapter. Furthermore, there are lots of other possible waveforms for an LFO. But the above named waveforms are the most common and popular ones.

Another setting often to be found is called Sample & Hold (S&H). This setting is not a periodic waveform, but just a periodic jump to a new value, e.g. on a clock pulse. Depen-ding from which original signal the Sample & Hold circuit drags the actual sample (for details refer to chapters 13 & 16), which is then held constant until the next clock or trigger is detected, the change of the values may be periodic, semi probabilistic or fully probabi-listic. In any case any periodicity will appear only at multitudes of the clock length and therefore often not be apparent to the listener.

Another possibility to create low frequency periodic waveforms is to use an envelope-CV and cycle this by retriggering at a certain point or after a certain time (what could be clock driven again). Some innovative envelope generators allow for the definition of loops on certain steps of the envelope too. Such a loop may end with the gate end and come to a fi-nal release phase, in case the character of an envelope shall be maintained. If it continues forever, the envelope is changing over to a kind of LFO, especially if it is externally trigge-red by a clock or self-triggered after some steps. In fact, early Buchla synthesizers did not even use dedicated LFOs but instead offered two stage loop envelopes for this purpose.

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Such looped envelope LFOs are usually started by a first gate or trigger signal, which defi-nes the first rising attack phase. This way the phase of the periodic waveform is defined by those signals. For an LFO the same locking of the phase of the waveform to an incoming signal is called Key Trigger. The opposite mode without synchronization of the wave-form is to simply let the waveform continue in Free Running.

Some sequencers allow for such high repetition rates that the running sequence of diffe-rent CV-levels may be seen as a periodic cycle and a possible waveform as such too. Find more explanations on sequencers below in chapter 14.

A further application of phase on LFOs is to have several phase shifted copies of the same waveform given to several outputs. Often such an LFO is called a Quadrature LFO and

the waveforms are output in four equally phase-shifted versions at 90° offset, as shown in the next graph for a triangle waveform. But there are different angles of start phase and other numbers of copies as well. This way an Octature LFO will have a differen-ce of phase of only 45° between its 8 copies. The modulation of similar parameters of the module setup with phase shifted LFO-wave-forms creates the impression of movements running one after another. One example in nature for such behavior is sea waves cons-tantly running on a beach. (Fig. 3)

Common frequencies for LFOs are 0.01 Hz to 30 Hz, with the corresponding cycle peri-od lasting from more than a minute to only 33 ms (10 milli seconds = 0.01 s). Most LFO modules cover at least 0.1 Hz to 10 Hz and the mostly used band is maybe 0.5 Hz to 2 Hz or 2 s to 0.5 s cycle period. The frequencies above 32 Hz are commonly called audio fre-quencies, as with increasing frequency the up and down of the periodic wave is not heard as a movement anymore but as a deep to midd-le high tone. 32 Hz is commonly rated as the lowest standard frequency still hearable as a tone to the human ear.

Many LFOs expand in their range into lower to higher audio frequencies too. Modulation of sound parameters at audio speeds are a separate topic presented in chapter 17 below.

Fig 2: Generation of a Pulse Wave

Fig. 3: Phase Shifting of a Waveform

Amplified toPulse Wave

Shifted Triangle Wave

time0V

voltage

time0V

voltage

Triangle Wave 0°-Phase




90°

180°

270°

time0V

voltage

time0V

voltage

time0V

voltage

time0V

voltage

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Part IIIMake them sing !

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Triangle, Sawtooth & Square

Classical Oscillator Concepts

Title: Analogue Solutions Colossus Mega-Synthesizer © Photo by Tom Carpenter

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17

Triangle, Sawtooth & Square – Classical Oscillator Concepts

Classic electronic sound sources are oscillators that produce a periodic waveform of vari-able frequency. This is the same process as introduced in chapter 09 for LFOs. And pretty often oscillators for audio applications are able to produce low frequency oscillation, too. So the first question is. What is the difference between these two frequency bands?

In general, oscillators are typically coupled in frequency to a musical input reference such as a voltage or MIDI information being transferred by a keyboard or sequencer. Whereas LFOs are mostly operating at constant frequencies. However, technically, the difference derives from the behavior of our ears! When we hear low frequency oscillation, our ears can follow the nature of the waveform up to a certain speed limit, be it the clicking of a square wave or the swelling of a triangle wave. This perception changes above 10 – 15 Hz (or periodic cycles per second) into hearing of a deep tone. Usually, the lowest frequencies perceived by healthy ears are given around 16 Hz but may vary with age up to 21 Hz. Other sources claim even 32 Hz, as a sine wave at that frequency needs already much amplitude (around 60 dB(A)) to be heard. On the other hand, the deepest note of a grand piano by standard is the lowest A0 with a frequency of 27.5 Hz and some grand pianos are even extended to the deep G0 or F0 at 24.5 and 21.8 Hz (based on a 440 Hz = A4 tuning). And those deep tones are clearly audible. So there must be something else about hearing deep tones, e.g. harmonics or distortion. Also our brain is often capable to “resynthesize” fun-damentals based on hearing their harmonics as will be explained in chapter 17.

The highest note of a grand piano or similar of a piccolo flute is given with C8 at nearly 4.2 kHz (4.186 Hz at 440 Hz tuning) and is still well below the upper limit of our hearing range, which is given around 20 kHz, but may vary down to 16 kHz with age. This highest piano note seems to be already pretty high in our perception, so again what are the higher frequencies good for? To explain this we first need to understand the tone spectrum!

Spectral Issues When hearing tones in the Hearing Range (i.e. 16 Hz – 20 kHz) our ears and brain can no longer follow the real waveforms but analyze the spectrum of the frequencies arriving. Mathematically, the simplest waveform with only one frequency is a sine wave. But all other periodic waveforms with that frequency may be described as the superposition of several sine waves. As those other sine waves need to fit in the same periodic cycle their frequencies are whole numbered multiples of the basic sine wave of the tone frequency. This coincidence is known as the Fourier theorem and a Fourier Transformation may be derived from that, thus converting our amplitude over time view of the waveforms into an amplitude over frequency view, which is called the spectrum of the tone or waveform.

The above named whole numbered multiples of the base sine wave are sometimes refer-red to as Overtones or Harmonics but it is much easier to understand them as Partial Tones with the Base Tone or Fundamental being the partial number one. Partial number two has then the factor 2 for its frequency hence sounds one octave higher. Partial num-ber three has factor 3 and sounds an octave plus a fifth higher. Number four is the second octave and so on. prel

iminary sa

mple

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This scheme is also known from Drawbar Organs, which offer nine partial sine waves for a free mixture defined by the drawbar positions. The possibility to add sine waves in order to create a tonal spectrum is known as Additive Synthesis in synthesizer terminology, but took years to be realized in an electronic product other than the limited approach of drawbar organs.

But back to our Classical Oscillators and their most common periodic waveforms!

• A Sine Wave is a sine wave and hence includes only the first partial in its spectrum

• A Triangle Wave adds all odd numbered partials with declining amplitude

• A Square Wave adds all odd numbered partials but with slower declining amplitude for higher frequencies

• A Sawtooth Wave adds all partials with declining amplitude

If you have an oscillator with a variable waveform you can easily compare that the sound is getting sharper or brighter the more partials are added. Therefore, Square Wave and Sawtooth are the most popular basic waveforms for a Subtractive Synthesis Scheme in East Coast Systems, as explained in chapter 4. In that subtractive scheme the oscilla-tor(s) produce a constantly sharp or harmonically rich signal that is reduced with a filter afterwards in its higher and/or lower partials. It is worth mentioning that the classical oscillators will sound as long as there is a Pitch-CV connected and any sound shaping in the East Coast approach is done with gates or envelopes working on the following filter and amplifier stages. However, it is also worth mentioning, that the first really popular east coast synth – the Mini Moog – increased the sharpness of its oscillators by overdri-ving the filter input with its amplitude hence producing additional distortion (compare chapter 23 below). It also offered another classic waveform, a combination of Sawtooth and Square Wave as shown in waveform and spectrum on the opposite page. Another po-pular possibility to sharpen the basic sound is to add some noise to it, as will be discussed in the next chapter.

Modular Oscillator ParametersAs explained in chapter 13, the basic information for the oscillator is which note to play and is defined by a Pitch-CV. This is why it is called a Voltage Controlled Oscillator or abbreviated VCO ! The corresponding parameter jack is mostly called 1V/Oct or fre-quency. Often a second jack called Pitch or FM (for Frequency Modulation) is found as well and may be used to detune the oscillator frequency dynamically in time. A common application is to connect an AD-envelope into pitch that is triggered to detune the start of the tone. The CV on the Pitch input maybe further controlled by an Attenuator to limit its influence but mostly has a much lower sensitivity than 1V/Oct, like 5V/Oct or even 5 V/semitone. It is worth checking this difference in order to determine the possibilities. If there is no jack for Pitch, the same effect may be accomplished by adding the desired devi-ation to the note information of the Pitch-CV in a CV-Mixer. But you need to make sure, that the 1V/Oct Pitch-CV is not attenuated by this process. Therefore, it is often better to

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time0V

voltageSine Wave

time0V

voltage

Triangle Wave

Sine Wave

Triangle Wave

frequencyF=1 2 3 4 5 6 7 8 9…

amplitude

amplitude

frequencyF=1 2 3 4 5 6 7 8 9 X 11

time0V

voltage

Saw Triangle(Moog)

Saw Triangle Waveamplitude

frequencyF=1 2 3 4 5 6 7 8 9 X 11…

time0V

voltage Rectangle orSquare Wave

time0V

voltageSawtooth Wave

frequencyF=1 2 3 4 5 6 7 8 9 X 11…

amplitude

amplitude

frequencyF=1 2 3 4 5 6 7 8 9 X 11 12 13

Pulse Wave 20%

time0V

voltage

time0V

voltage

Pulse Wave 33%

frequency

amplitude

amplitude

frequencyF=1 2 3 4 5 6 7 8 9 X 11 12 13

F=1 2 3 4 5 6 7 8 9 X 11 12 13

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limit the influence of the CV for the Pitch deviation first and then use a Precision Adder module to combine both voltages before connecting to the oscillator‘s 1V/Oct input.

A counterpart to the above named jacks are knobs to determine the Frequency, Tuning and Fine Tuning. Other denominations are Coarse Tuning for the Frequency or a selec-tor switch for the basic octave, classically given as 32’, 16’, 8’, 4’ and 2’ as known from the length of organ pipes in the corresponding octaves. Those knobs create CVs internally which are added to the CVs input at the jacks. Therefore, it is worth noting that tuning an oscillator is a basic work in most classical concepts. Even more if one knows that most old classical oscillators were infamous for detuning over time due to component heating or when exposed to different climate conditions within a location. Today, most analog oscillator circuits are temperature compensated and show only little detuning if at all. The development of Digitally Controlled Oscillators (DCO) made detuning mostly ob-solete and is the reason why nowadays only few people talk about it at all.

Another important parameter for classical oscillators with Square Wave generation is PWM which stands for Pulse Width Modulation. The principle was already explained in chapter 9 for LFOs. A Pulse Wave is similar to a Square Wave but the ratio between high and low voltage duration may be manually altered as mentioned above or modulated. Usual values are 10% to 50% for the duration of the positive voltage. The sound is getting sharper and thinner with smaller values of this percentage but values over 50% behave vice versa as for the sound and spectrum 40% = 60%, 30% = 70% and so on. As 0% is no valid option the PWM input jack will usually accept a CV for a certain range of let’s say 10%-50%. As the range of these CVs are dependent of the electronic circuit you should check, which voltage is needed to get the whole effect. If the input is designed for +/- 8 V you will hardly get the full effect with a CV that is produced on a 0-5V level. On the other hand, most PWM inputs are paired with an attenuator, so it is easy to limit the effect if the supplied voltage is higher.

A variable pulse width for a square wave is a parameter being found in many classical synthesizers. However, it is technically possible and becomes more and more popular to vary the symmetry of other wave shapes such as Triangle or Sawtooth, too. As a result, the harmonic spectrum of such an oscillator generating a waveform being variable in its symmetry can also provide different sounding spectra. An example of Symmetry Modu-lation of a Triangle Wave is shown on the opposite page.

Most oscillators have additional parameter jacks like Sync and FM which are needed for coupling with other oscillators which will be described in chapter 17.

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Left: 10% Symmetry Modulation of a Triangle Wave creates needle peaks without clear fundamental, Right: Spectrum of the waveform

Left: 25% Symmetry Modulation of a Triangle Wave creates needle peaks with Ramp, Right: Spectrum of the waveform, the fundamental is back

Left: 35% Symmetry Modulation of a Triangle Wave adds a swerve, Right: Spectrum of the waveform, partials are reduced

Left: 48% Symmetry Modulation of a Triangle Wave creates nearly the Triangle, Right: Spectrum of the waveform with fewest partial intensity

Paolo Groppioni is based in Monte Porzio Catone nearby Rome, Italy. He started buil-ding analogue synthesizers as a hobbyist and without commercial intentions in 2000. After meeting Austrian synthesizer collector Theo Bloderer who encouraged him, this changed with the first production models A8 and A4 that earned his company GRP a high reputation in the market. In 2017, the models A2 and R24 were added which could be used standalone or in a 5U frame. They are based on compatible equipment from synthesizer.com. Since 2018, a series of twelve modules in Eurorack format around the classic basic components of his synthesizers has been added to the product line.

What‘s your approach in designing new modules?

I am deeply convinced that it is fundamental to keep the quality of materials and circuits at highest levels, no matter if used for standalone or Eurorack machines. The choice of the function, the design and the ergonomics for the user are the essential parameters in my development of new modular units.

In order to avoid quick wear the electro-mechanic parts of a module are the most important issue for a long-lasting joy with them. I.e. all jacks, potentiometers with stable axis, knobs etc. are under continuous operation and therefore experience minimal but steady wear. Electronic parts vice versa will operate under much less impact during the module’s use.

GRP Synthesizers Paolo Groppioni

Title: Paolo Groppioni and his Grp A4 © Photo by Paolo Groppioni

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So the engineering is twofold: find a robust and technically sturdy electromechanical inter-face is one side and combine it with a good sounding electronic circuitry the other one. This is one reason, why many module manufacturer often have similar module layouts for differently sounding electronics.

Where do you see the future of modular synthesis?

I believe, that modular systems, let aside fashions, will play a major role today and in the future. The flexibility of connections, the possibilities to configure a personalized system and not to forget the uncountable advantages to really understand what is going on, are unique selling points for modular systems. And there is a lot more possible and to discover far beyond the pure modularization of existing synthesizer concepts.

Do you wish for additional communication standards?

Keeping to the field of modular systems, I believe that a definite protocol for all brands of those could make it possible to integrate polyphonic synthesis as well. However, such a communication system between modules would have to be digital to keep connections simple and independent of the number of voices.

But then it would probably need a common association of the manufacturer’s to find a common standard which is still easy enough to be incorporated in all relevant systems.

What‘s the importance of polyphony in a modular system?

Polyphony with modular systems could make this type of synthesizers really complete. I am convinced however, as already said, that a definite protocol is needed to solve the problems of supplying the necessary information to a number of interacting modules as otherwise the needed cabling would unnecessarily limit possibilities and joy to use such polyphony.

Some manufacturers have started to incorporate MIDI connections in a TRS 2.5 mm jack. But there is no common standard, how the signals are linked to tip and ring. And is it really the old and slow MIDI standard to define the new polyfonic data exchange or its newest implementation MPE or should a new standard not have a much higher resolution in all parameters? But this is not a question of modular alone. The whole industry must agree on such vital changes and nothing in this direction has happened in the last decades.

Which other manufacturer‘s module impressed you most lately?

I must admit, that I don’t have enough time to test modules of other designers. I do have contact with Simone Fabbri of Frap Tools and David Mancini of Sound Machines: they pro-duce very interesting cabinets, modules and elements of bidimensional control for parame-ters. It is always exciting to meet people at fairs and exhibitions, with cables and patches…

www.grpsynthesizer.it

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Symbole1V/Oct�-scheme 101

5D Sensors 86

AAAX 229

Accent 105

Accent Function 212

ADAT-lightpipe interface 94

Additive Synthesis 28, 114

AD-envelope 211

Aftertouch 85, 136

Algorithm 136

Aliasing 195

All Pass Filter 157

AM 128

Ambience 182

Amplitude 69

Amplitude Modulation 128

Analog Sequencer 105

APF 157

Arpeggiator 99

Attack 63, 177

Attenuator 77

Attenuverter 77

AU 229

Audio Interfaces 94

Audio Unit 229

Auxiliary Sends 78

Avid Audio eXtension 229

Azure Noise 122

BBand Pass Filter 157

Band Reject Filter 157

Band Stop Filter 157

Base Tone 113

BBD 183

Beating 187

bi-polar 69

Bipolar CV 77, 85

Bit Crusher 196

Bit Resolution 195

Blue Noise 122

Boost 172

BPF 157

Breath Controllers 86

Brownian noise 122

Bucket-Brigade Device 183

Buffered Multiples 47

CCapacitor 64

Carrier 135

Channel Aftertouch 92

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Channel Volume 78

Chase Light Programming 107

Chord Generator 99

Chorus 188

Chromatic Scale 101

Circuit Bending 22

Classical Oscillators 114

Classic Waveforms 69

Clean Channel 171

Clipping 172

Clock 53

Clock Divider 54, 128, 203

Clock Multiplier 54

Cloud

CMOS-Circuitry 43

Coarse Tuning 116

Comb Filter 187

Complementary Metal-Oxide-Semiconductor 43

Compression 176

Continuous Controllers (CC) 92

Control Voltage 63, 69, 77

Critical Distance 182

Crunch 171

Current Draw 44

CV 63, 69

DDAC 143

DAW 229

DAW-Controllers 85

DCA 136

DCO 116, 143

DC-Offset 79

Decay 63

De-Esser 164

De-Essing 177

Delay 69, 181

Digital Audio Interfaces 94

Digital Audio Workstation 229

Digital Controlled Amplifier 136

Digitally Controlled Oscillators 116, 143

Digital Oscillators 143

Digital Sequencers 105

Digital to Analog Converter 143

Digital Waveshaping 196

Distortion 172

DIY 271

Doppler Effect 191

Drawbar Organs 114

Drawbars 87

Drive 172

Drum Machines 106

Dry/Wet-Balance 182, 187, 190

Ducking 177

EEarly Reflections 182

East Coast Systems 27, 114, 217

EDM 203

Electronic Dance Music 203

Encoders 86

Ensemble Effect 188

Envelope Follower 85, 94, 165, 177

Equalizer 157

Exciter 153

Expansion 176

exponential 64

FFader 78

Feedback 183, 187, 190, 196

Fender Rhodes Piano 211

FETs 129

Field Effect Transistors 129

Filter Emphasis 163

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Filter-FM 163

Filter Key Tracking 159

Fine Tuning 116

Finger Drumming 107, 212

Fixed Filter Bank 158

Flanger 187

FM 135, 212

Formants 146

Fourier Row 28

Fourier Transformation 113

Free Running 71

Frequency 69, 116

Frequency Modulation 135

Frequency Modulation Synthesis 135

Frequency Ratio 136

Frequency Shifter 129

Fundamental 113, 127, 187

Fundamental Frequency 28

Fuzz 172

GGain 171

Gate 53

Gate Length 59

Grains

Granular Synthesis

Graphic Equalizer 158

Groove Boxes 106

HHard Disk Recording 229

Hard Knee Characteristics 177

Hard Sync 130

Harmonics 113

Headroom 145

Hearing Range 113

Heterodyning 129

Highest Note Priority 93

High Pass Filter 157

Hold 63, 65

Homophony 94, 222, 223

HPF 157

HUI 249

Humanize 105

Human User Interface Protocol 249

IInterference 187

JJoystick 86

KKey Trigger 71

Key Velocity 85, 136

Knob 85

LLag-Generator 63

Last Note Priority 93

Latch Mode 99

LED 159

Leslie 191

Level 171

LFO 69

Light Emitting Diode 159

Limiting 176

linear 64

Lo-Fi Effect 195

logarithmic 64

Logic Gates 55

Looper 183

Loop Length 183

Lowest Note Priority 94

Low Frequency Oscillator 69

Low Pass Filter 157

Low-Pass-Gate 29, 159

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LPF 157

LPG 29, 159

MMass 77

Master Keyboards 85

Max 230

Microphone Input 95

MIDI Modular Synthesizers 23

MIDI standard 91

MIDI-to-CV converters 92

Mixer 77

Modular Samplers 147

Modular Synthesizer Systems 21

Modulation Wheel 92

Modulator 135

Mod Wheels 86

Monophonic 93, 221

Monophony 223

Motion Sequencing 107

Multiband Compression 177

Multicore Cable 95

Multiple Modules 45

Multi-Sampling 146

Multitimbral 222, 223

Musical Instruments Digital Interface - MIDI 91

Mute Button 79

NNoise 100, 211

Noise Gate 177, 211

Noise Generator 121

Non-Harmonic Spectrum 211

Normalization 146, 176

Normalized Inputs 79

Notch Filter 157

Notch Filters 187

Note-Off-Command 92

Note-On-Command 92

Nyquist Theorem 147

OOctave 101

Open Sound Control 249

Operator 135

Optocoupler 91, 159

OSC 249

Oscilloscope 59, 122

Overdrive 172

Overdrive channel 171

Overtones 113

PPanorama 78

Parametric Equalizer 158

Paraphonic Mode 127, 190, 221, 223

Partials 28, 187

Partial Tones 113

Patch Cables 44

Patching 271

Pattern-Chaining 107

Pattern Generator 212

Pattern Sequencer 107

PCB 43, 275

PD 138

Phase 69

Phase Distortion Synthesis 138

Phase Locked Loop (PLL) 94

Phase Shifting 71, 189

Physical Modeling 151, 212, 229

Ping-Pong-Delay 183

Pink Noise 122

Pitch 114

Pitch-CV 101, 114

Pitch Shifting 190

Pitch Wheel controller 92

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Playback Direction 99, 105

Plug-Ins 229

PM 151, 212

Polarized Mixers 78

Polarizer 77

polyphonic 93

Polyphonic Synthesizer 221

Polyphony 94, 223

Potentiometer 64, 77

Power Chords 128

Power Rating 44

Power Supply Units 43

Precision Adder 116

Pre/Post Fader Routing 78

Pressure 85

Printed Circuit Board 43, 275

PSU 43

Pulse Wave 70, 116

Pulse Width 70

Pulse Width Modulation 116

Push Buttons 85

PWM 116

QQuantizer 99

RRacks 35

Ramp 70

Random CV 204

Ratcheting 105

Real Time Audio Stream 229

Real Time Programming 107

Red Noise 122

Release 63

Release Times 177

Reset 59

Resistor 64

Resonance 163

Resonator 153, 164, 196

Re-Synthesis 28

Reverb 181, 182

Reverberation Time 182

Rhythm Pattern 205

Rhythm Sounds 211

Ribbon Controller 86

Ring Modulation 128

Ring Modulator 129

RM 128

Roll 105

RTAS 229

SSample 143

Sample Frequency 145, 146

Sample & Hold 70, 122

Sample & Hold Generator 100

Sample Loop 145

Sample Resolution 143, 145

Sampling 145, 151, 183, 195, 213

Saturation 159, 172

Sawtooth Wave 70, 114

Seaboards 86, 93

Self-Oscillation 163

Semi-Modular Synthesizers 22

Semi-Parametric Equalizer 158

Sequencer 29, 105

S&H 70, 204

S&H device 100

Side-Chain Input 177

Sine Wave 69, 114

Slew Rate Limiter 63

Slider 85

SMD 277

Soft Knee Characteristic 177

Soft Sync 130

28

Software Modular Synthesizers 23

Software Sequencers 106

Song 107

Sound Design 137

Space Sound 183

Spectrograph 122

Spectrum Analyzer 122

Square Wave 70, 114

Stackable Cables 46

Start 59

Step Programming 107

Step Sequencer 107

Stereo Mixers 78

Stop 59

Subharmonic Oscillators 130

Sub-Oscillator 128

Subtractive Synthesis Scheme 114

Supersaw Oscillator 221

Surface Mounted Devices 277

Sustain 63

Swarm Oscillator 221

Swing 105

Symmetry Modulation 116

Synchronization 130

Synclavier 135

Synth Expanders 23

TTape Delay 183, 187

TDM 229

Tempo 59

The MIDI-Manufacturers Association (MMA) 91

Theremin 129

Threshold Level 176

Through-Hole-Technology 277

THT 277

Time Division Multiplexing 229

Time-Level-Envelopes 65, 136

Time Stretching 147

Time-Stretching/-Compression

Total Recall 244

Touch Pads 86

Touch-Plate Keyboard 85

Touch Strips 86

Transistor Ladder Filter 158

Transistor-Transistor-Logic Circuits 43

Triangle Wave 69, 114

Trigger 53

Trigger Pads 85

Trigger Sequencer 106, 203, 212

Trill 135

Trimmer 64

TTL-voltage 43

Tuned Percussion 211

Tuning 116

UUAD 229

uni-polar 69

uni-polar CV 77

Uni-Polar Modulation CV 85

Unison 223

Universal Audio Digital 229

USB MIDI 93

VVA 152, 231

Vactrols 159

VCA 63, 79, 128

VCF 157

VCO 114

Vector Synthesis 144

Vibrato 135

Video Projection 196

Violet Noise 122

Virtual Analog Synthesis 152, 229, 231

29

preliminar

y sample

Virtual Studio Technology 229

Visual Elements 196

Vocoder 165

Voice Modules 217

Voltage Controlled Amplifier 63, 79

Voltage Controlled Filters 157

Voltage Controlled Oscillator 114

Voltage Controlled Switch 54, 203

Volume 171

Vowel Filters 163

VST 229

WWaveform 69

Wave Shaping 138

Wavetable Synthesis 144

West Coast Approach 27, 137, 217

West Coast Systems 29, 63, 139, 159

White Noise 121

Width Factor HP 34

Wind Controllers 86

XXLR 95

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modularworlds2 1 0 werbemuster - synmag · jean-michel jarre needs to be credited as one of the...

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