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Modular Synthesis Explained

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You may be wondering what is a modular synth or what is modular synthesis. In this tutorial, I'll explain the history of modular synthesis leading to modern systems. 

I'll explain modules, systems, the history behind them and why they're increasingly relevant to modern music.


Synthesizer and modular development began around 1963-64 when Robert Moog (1934-2005) and Don Buchla (born 1937) invented several parts and concepts to be used in a system called the modular synthesizer.

Moog worked in New York, the eastern part of USA, while Don Buchla lived in San Francisco, the western part of USA. They worked independently of each other, and later the Moog concept was called East Coast philosophy and the Buchla concept was called West Coast philosophy.

Moog 55Moog 55Moog 55
Moog Model 55 / Wikipedia / Kimi95

Moog, Buchla and ARP

Though Moog and Buchla were pioneers in this field, in 1969 Alan Robert Pearlman founded ARP instruments, or ARP, and had a degree of success. 

When synths became more portable and Minimoog was a hit, the semi-modular ARP 2600 synth became the opponent with great sound, great functionality and a cheaper price. 

Of course the prices were huge back then, but it formed a trend and simple synths became more affordable later.

ARP 2600ARP 2600ARP 2600
The ARP 2600 semi-modular synth / Wikipedia / Daniel Spils

Making a Hit Synth Brand

Originally Moog asked opinions and worked with several musicians to perfect his synth. He decided to make it an instrument to be used for musical purposes and melodies. 

Over time the Moog brand became a great success and became synonymous with the synth term. Often people still identify synth with Moog synonymously.

Buchla, however, didn’t care for serving the mainstream and his products remained pricey and esoteric and primarily used for sound design and experimental music.


Modular synths can be broken down into its components which are called modules

Each module has a specific function and they can be connected with patch cables using the inputs and outputs. 

The current that flows in the machine controls the parameters of each module.

There are two types of signals: 

  1. CV—control voltage, useful for sound sources and modulation
  2. Gate—gate is an on/off switch or a trigger event

These include:

  • Sound sources (VCO, white noise): this can be a voltage controlled oscillator or a noise generator
  • Filters (VCF): in East Coast philosophy this removes some of the frequency of the sound source
  • Amplifiers (VCA): this amplifies a signal in response to a control voltage
  • Waveshaper/wavefolder: in West Coast philosophy this makes a sound source sharper or more metallic sounding
  • Low pass gate (LPG): in West Coast philosohpy this is a combination of a low pass gate and an amplifier, to create short, plucky sounds. Search youtube for Buchla Bongo to understand its sound
  • Envelope generator (EG): this provides a single shaped voltage, triggered by the gate signal
  • LFO: this is a continuous modulation source used to control other modules.
  • Mixer: a module which combines voltages
  • Ring modulator (RM): combines two signals and creates the sum and difference of their frequencies
  • Sequencer (SEQ): this produces a sequence of voltages, which can be targeted to control oscillators, filters and so on. The sequence can be looped infinitely and the speed can be set dynamically with an LFO acting as a clock signal (square output).

Eurorack modularEurorack modularEurorack modular
Eurorack system with various brands, Make Noise, Tip Top and Intellijel / Youtube / Luke Killen


The following are some modern examples on how to plan a system.

Moog Modular—Model 15

  • 2 x VCA
  • 1 x VCF
  • 1 x Fixed Filter Bank
  • 2 x EG
  • 2 x VCO
  • 1 x Noise

Moog Modular—Model 35

  • 3 x VCA
  • 2 x VCF
  • 1 x Fixed Filter Bank
  • 3 x EG
  • 4 x VCO
  • 1 x Noise

Doepfer A-100 Mini-System

  • 2 x VCO
  • 1 x RM
  • 1 x Noise
  • 1 x VCF
  • 1 x VCA
  • 1 x Mixer
  • 1 x EG
  • 1 x LFO
  • 1 x MIDI-to-CV/Gate/Sync Interface

Make Noise 0-Coast (semi-modular)

  • 1 x VCO
  • 1 x VCA
  • 1 x Overtone & Multiply (harmonic interest without filter module)
  • 1 x LPG
  • 1 x LFO
  • 1 x EG
  • 1 x MIDI to CV interface
  • 1 x Random and Clock module

Pittsburgh Foundation 3.1

  • 1 x MIDI to CV interface
  • 2 x Waveforms
  • 1 x LFO
  • 1 x Mixer
  • 1 x Toolbox
  • 1 x MixMult
  • 1 x LPG
  • 1 x VCF
  • 2 x EG
  • 1 x Dual VCA
  • 1 x Out

Today's Modulars

Fortunately today’s hardware synthesizers are cheaper than ever thanks to modern planning, manufacturing, brands and trends. In the 1970s a modular could be had for a price of a large house, now you can buy as low as around US$1000-2000.

Modern modulars include digital modules, which are pitch perfect despite heat, unbelievable sounds, modulation sources and sound design capabilities. There are around hundred brands and thousands of modules, which includes commercial and artisan / DIY products.

Make Noise SystemMake Noise SystemMake Noise System
A full Make Noise system in action / Youtube / Barry Wood


I recommend these manufacturers based on the range and type of modules on offer.

Doepfer, Pittsburgh and Analogue Solutions are on the cheap side, while others are West-coast types, multi functional modules and expensive ones.


Software modulars are a very cheap way into creating complex sounds or to have the workflow you are into with virtual cables.


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u-he Bazille software synth


Free beta

Sonigen Modular



This tutorial was an introduction to modular synthesis, hardware and software. I explained the history, brands, systems and modules. 

If you want to get into the hardware world cheaply you can start with semi-modular synths and adding some modules with a small empty powered case. Don’t forget to buy some cables as well. Happy learning and patching.

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