Voice-Stealing

What a keyboard or synthesizer does when it runs out of voices (notes of polyphony), but continues to receive note on commands. Actually, some keyboards will (or can be set to) ignore any note commands that come in if all available voices are already in use. However much of the time what happens is the oldest note – the first note played that is still sounding – will be cut off so the machine may play the new note. This is voice-stealing. There are many sophisticated methods of voice-stealing in use that go well beyond simply taking the oldest note away. For example, many machines will not take the lowest note playing because in the context of a performance it is very apparent when that note drops out. The algorithm used to decide which notes get stolen under these circumstances can have a profound impact on the ‘apparent’ polyphony of a keyboard or sound module.