Yamaha SY77 Operating Manual page 25

Play up to 16 AFM notes
and 16 AWM notes at
once
A Drum voice consists of
61 percussive sounds
The one two or four elements in a voice can produce many types of keyboard
split and layer effects.
On earlier Yamaha synthesizers such as the DX7-II, layers and splits were
created by combining two or more Voices into a "Performance". This meant that
sometimes you played Voices and other times you played Performances.
However on the SY77, layers and splits can be included in a voice, so you can
simply select a voice and play without considering whether it contains layers or
splits.
The SY77 contains two tone generators; an AFM tone generator and an AWM
tone generator. The AFM tone generator can produce up to 16 simultaneous
notes of FM sound, and the AWM tone generator can produce up to 16 simul-
taneous notes of digitally sampled sound.
Some voices consist of only one element, some of two elements, and others
of four elements. (The Voice mode setting inside each voice determines how
many elements are used.) The important thing to remember is that up to a total
of 16 notes of AFM sound and 16 notes of AWM sound can be sounding at any
time. If a voice plays two or more elements for a single key, the sound will be
more complex and richer, but you will be able to play fewer simultaneous notes.
In addition to the "normal" voices explained above which consist of one two or
four elements, the SY77 provides a special type of voice; the Drum voice.
A drum voice has no elements, but consists of a different AWM sample for each
of the 61 keys of the SY77 keyboard.
A drum voice can be played from the keyboard just like a normal voice.
Usually you will use a sequencer to play a drum voice, providing drums and
percussion accompaniment. Either the SY77's internal sequencer or an external
MIDI sequencer can be used to play a drum voice.
There is no distinction between normal voice memory and drum voice
memory; either type of voice can be stored in any of the voice memories.
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