1 volt per octave is a control voltage used to determine pitch information sent from a keyboard.


ADSR is Attack Decay Sustain Release, a type of envelope generator with four stages. The attack of the sound where it builds up to its initial peak when you press the key. The decay of the sound where it goes back down in volume. The sustain level where it remains until the player releases the key. The release where the sound fades out.

Aliasing Distortion

Aliasing distortion is when an audio signal contains frequencies above 1/2 the sampling rate. Those unwanted frequencies above the sampling rate are mirrored back into the sample rate range and can be heard.


An amplifier boosts a signal and at the same time can be voltage controlled to change the signals amplitude over time.


A device that steps from note to note for whichever keys are pressed (or latched) in a preset. The mode control determines which direction the notes play. The range control determines how many octaves the notes will repeat. The rate control determines the speed of the notes changing.


The time taken for an envelope to achieve maximum amplitude after it has been triggered on by a gate signal.

Band Limited

Band limited audio does not contain any frequency content above 1/2 the sampling rate. Band limiting an audio signal prevents aliasing distortion.

Band Pass Filter (BPF)

A band pass filter removes frequencies below and above the cutoff frequency from the sound.


Beats Per Minute.

Control Voltage (CV)

Control voltages are a signal used to control a parameter of a module, such as the frequency modulation amount of a filter.

Cutoff Frequency

Cutoff frequency refers to the frequency at which a filter removes other frequencies (depending on the type of filter).


Second phase of an ADSR envelope.


Dissonance is an unstable or inharmonic sounding tone.


Any form of audio signal processing that alters the original sound.

Envelope Generator (EG)

An envelope generator generates a signal that changes over time, normally to control the loudness of the sound. EGs are also used to control other parts of the synthesizer, such as the filter.


A filter removes certain frequencies of a sound. Filters have two main controls, frequency and resonance.


Frequency is the measurement of a repeating event such as a waveform of an oscillator. Frequency is typically measured in hertz (hz).


Gate is a signal used to trigger an event, such as the attack and release phase of an envelope.

High Pass Filter (HPF)

A high pass filter removes frequencies below the cutoff frequency from the sound.

Hertz (hz)

Hertz are measurement unit for frequency and are on a scale of cycles per second. So 10 hz is a repetition of 10 times per second.

Low Frequency Oscillator (LFO)

A Low Frequency Oscillator is similar to a normal oscillator except that it outputs very low frequencies and is used as a controller signal to modulate a parameter.

Low Pass Filter (LPF)

A low pass filter removes frequencies above the cutoff frequency from the sound.


MIDI (Musical Instrument Digital Interface) is a standard digital means to connect musical instruments together. In modular, MIDI is used to allow you to connect an external keyboard or sequencer to play the synthesizer.

Modular Synthesizer

A modular synthesizer is one where the structure of the synthesizer isn't fixed. There are a variety of modules which can be plugged into each other. Each module is specialized for a single function of the synthesizer. A modular synthesizer offers great flexibility but has a steeper learning curve.


A module a device that is responsible for a single function of a modular synthesizer.


Monophonic is one sound. A monophonic synthesizer can play only one note or sound at a time. Modular is a monophonic synthesizer.


An oscillator produces a repeating waveform at a frequency controlled by voltage. Oscillators typically have the option to change the frequency and waveform.


An adjustable performance effect that glides or bends the pitch from one note to the next. Slew limiters can be used for a portamento effect.

Pulse Wave

The pulse wave has a complex set of harmonics depending on what the pulse width position is. At 50% pulse width, the harmonic content is only odd harmonics which is the same as a square wave.

Pulse Width

Pulse width is the duty cycle of a pulse wave, typically in percent values. A pulse width of 50% has equal positive and negative phase lengths and is considered a square wave.


The time taken for an envelope to achieve minimum amplitude after it has been triggered off by a gate signal.


Resonance is a feedback loop from a filters output back into its input. The resonance control is the amount (in percent) of the signal being fed back to the input. This feedback creates an emphasis at the cutoff frequency. When resonance is increased, it also typically reduces frequencies that are not near the cutoff frequency.

Ring Modulator

A ring modulator takes two signals and multiplies them and outputs the result. The resulting frequencies are called sidebands which are the sum and difference of the two original signal frequencies. Ring modulation creates a dissonant, metallic sound.

Saw Wave

The sawtooth wave contains all harmonics.

Sine Wave

The sine wave is a single cyclic waveform that contains only the fundamental frequency and has no additional harmonics.

Slew Limiter

A slew limiter takes a signal and slows down any changes in its value. For example, if the signal is a keyboard note in 1v/oct, and the note changes, instead of instantly changing to the new note being played, the signal smoothly glides to the new note in a portamento type effect.


A sideband is an additional frequency created above or below the original signal. This is a typical effect of various types of modulation.


A socket is an input or output connection on a module which receives or sends a signal.

Square Wave

The square wave contains only odd harmonics.

Subtractive Synthesis

The technique of creating a desired timbre by filtering waveforms rich in harmonics.


Sustain is the level at which an envelope generator stays at after the decay phase. Sustain is typically measured in percent.

Sync (oscillator)

Oscillator sync is a function where a signal retriggers the oscillator waveform phase. A typical sync source is another oscillator, but any controller can be used to retrigger the oscillator.

Sync (tempo)

Tempo sync is a function where an cyclical event such as an oscillation is scaled to a tempo value.


The tone and character of a sound.

Triangle Wave

The triangle wave has only odd harmonics, with every other harmonic inverted and at reduced amplitude.

Voltage Controlled

Voltage controlled is a device that is controlled by an electrical signal. Modular behaves similar to a voltage controlled synthesizer, but it is not truely voltage controlled. We decided to use this terminology so that our synthesizer is more familiar to those who traditional synthesizers.

Voltage Controlled Amplifier (VCA)


Voltage Controlled Filter (VCF)


Voltage Controlled Oscillator (VCO)



A waveform is a repeating signal typically created by an oscillator. A waveform can also be random in the case of noise.


A wire is used to connect input or output sockets on a module.