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