A modular synth is made up of different modules, each with a simple function. This page covers the different types of modules and what they do.

Oscillators

Oscillators are the sound source of a modular synth. They generate a waveform that can be shaped and modulated to create different sounds. The basic waveforms are sine, square, triangle, sawtooth, and noise. Each waveform sounds different.

Waveforms

Think of waveforms as the most basic sound. They are the building blocks of all sounds.

Voltage Controlled Oscillators (VCOs)

Voltage Controlled Oscillators (VCOs) are the most common type of oscillator. They generate a waveform with a frequency that can be controlled by a voltage. For every 1 volt increase, the frequency goes up an octave (which doubles the frequency).

Frequency Modulation (FM) Oscillators

Frequency Modulation (FM) Oscillators are a type of oscillator that can modulate the frequency of another oscillator.

Filters

Filters are used to shape the sound by removing certain frequencies. The most common types of filters are low-pass, high-pass, band-pass, and notch filters. Each filter type removes different frequencies from the sound.

Envelope Generators

Envelope generators are used to shape the amplitude of a sound over time. The most common type of envelope generator is the ADSR envelope, which stands for Attack, Decay, Sustain, and Release. Each stage of the envelope controls a different aspect of the sound’s amplitude.

  • Attack: How quickly the sound reaches its maximum amplitude.
  • Decay: How quickly the sound drops to the sustain level.
  • Sustain: The level of amplitude while the note is held.
  • Release: How quickly the sound fades to silence after the note is released.

Low-Frequency Oscillators (LFOs)

Low-Frequency Oscillators (LFOs) are used to modulate other parameters of the sound. They generate a waveform at a low frequency (usually below 20 Hz) that can be used to modulate parameters such as pitch, filter cutoff, and amplitude.

Voltage Controlled Amplifiers (VCAs)

Voltage Controlled Amplifiers (VCAs) are used to control the amplitude of a sound. They take in an audio signal and a control voltage, and output the audio signal at a level determined by the control voltage.