Synthesizer voice

The block diagram for a very basic synth voice. Inputs on the left, outputs on the right and control inputs below.
A synthesizer voice is an individual audio circuit path in a synthesizer which produces an individual sound.

Signal flow

Even with multiple oscillators, a typical monophonic synthesizer has a single voice and only one key at a time can be used to sound a note. On a polyphonic synthesizer, as many keys will sound simultaneously as the instrument has voices.[1]

The simplest standard voice is made up of a VCO, a VCF, a VCA and the envelope generator to give the note timbre and dynamics (changes in loudness). In a polyphonic synthesizer, each voice is a parallel signal path with its own oscillator, filter and amplifier. A paraphonic synthesizer plays several notes at once, however they all go to a single filter.[1][2][3]

Sometimes voice is also used to refer to a preset instrument-like sound.[1][4]

Rather than have a voice for each key, a polyphonic synth's keyboard will use voice allocation to allocate a voice to whichever key is pressed. Exceeding the maximum polyphony results in voices cutting out abruptly.[4]


  1. ^ a b c Synthesizer Basics edited by Brent Hurtig, GPI Publications (Hal Leonard Pubs), 1984, ISBN 0-88188-714-5, p. 121
  2. ^ The complete synthesizer by David Crombie, Omnibus Press, 1982, ISBN 0711900566, p. 15
  3. ^ The new complete synthesizer by David Crombie, Omnibus Press, 1986, ISBN 0711907013, pp. 23-26
  4. ^ a b Roland - Digital pianos FAQ