Appendix H. Midi Messages In-Depth; Program & Bank Changes - M-Audio Keystation Mini 32 User Manual

Appendix H: MIDI Messages In-Depth
Program & Bank Changes
When the MIDI standard was first established, it enabled the user to access only 128 different sounds using program
change messages (0-127). As MIDI devices grew to be more sophisticated and contain more sounds, bank change messages
were included in an updated MIDI specification to allow for more than 128 sounds to be accessed.
The language MIDI uses to communicate
between musical instruments only allows
for program change commands 0-127, for a
total of 128 possible programs (127 pro-
grams + program "0" = 128 programs total).
Because of inherent limitations of the MIDI
communication protocol, the number of
directly accessible programs (using pro-
gram change messages) cannot easily be ex-
panded beyond 128. Thus, a system of
banks, with 128 sounds in each, has been
created that enables manufacturers to over-
come the 128-sound MIDI limit.
128 banks with 128 sounds in each bank is
the basic principle used to expand the
number of accessible sounds. However, to
avoid reaching the new limit of the result-
ing 16,384 possible sounds (128 banks x
128 programs) accessible using a bank
change combined with a program change,
another layer of banks was added. The re-
sult is a system of 128 banks that can con-
tain 128 sub-banks in each of them, which,
in turn, can contain 128 sounds (programs)
within them.
Bank change messages are useful when call-
ing up sounds from a large library that may
exist in a particular sound module or soft-
ware synthesizer. For example, devices that
are built according to Roland's GS specifica-
tion or Yamaha's XG specification require
you to specify a bank change in order to ac-
cess the extra voices that these devices pro-
vide.
Keystation Mini 32 User Guide Appendix H: MIDI Messages In-Depth
34