Structure And Function Of The Scb-55; Parts; Voices And Polyphony - Roland SCB-55 Owner's Manual

3. STRUCTURE AND FUNCTION OF THE
SCB-55

(1) Parts

The SCB-55 provides 16 Parts, and thus allows for a maximum of 16 different perfor-
mance parts to be played at the same time. Part 10 is for playing percussive instrument.
A Part is something like an orchestral part; think of it as a group of musicians all playing
a particular instrument. The big difference compared with a regular orchestra is that you
are completely free to decide what kind of instrument they will be playing. In addition,
you can change that instrument midway through a song (as many times as you want) for
every different part. You could think of this group as being made up of incredible multi-
instrumentalists who can play any instrument you give them.
There are many different kinds of performance data in MIDI, but probably the most basic
is the note message determining which key to play, how hard, for how long, and when
to start. Every part has its own MIDI channel over which it receives performance data
and, unless you reset it for some reason, the channel number is the same as the part
number.
Each part plays by following the instructions in the performance data on its own chan-
nel, and pays no attention to the data on other channels intended for other parts. So
thanks to this MIDI channel scheme, you can play each Part completely independently
of the others, like on a multitrack recorder.
* As to MIDI, refer to "ABOUT MIDI." (p. 8)

(2) Voices and Polyphony

The SCB-55 contains 28 internal components (Voices), each of which is capable of gen-
erating sound. All 28 Voices can operate simultaneously. However, some sounds
require 2 Voices to produce one note. For this reason, the number of notes actually
available can be 28 or less. For example, if every sound you are using consists of 2
Voices, the maximum number of notes you could play at once would be 14.
To determine how many Voices the SCB-55 is using, add up the number of Voices used
by all the Parts. Note that it is possible to have all 28 Voices working to produce the
sound of only one Part.
For information on the number of Voices used by particular sounds, refer to the "TONE
TABLE" (p. 14).
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