Midi Messages In-Depth; Program & Bank Changes - M-Audio KEYSTUDIO KeyStudio 49i User Manual

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KeyStudio 49i User Guide 30

MIDI Messages In-Depth

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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 programs + program "0" = 128 programs total) Because of inherent limitations of the MIDI
communication protocol, the number of directly accessible programs (using program change messages) cannot easily be expanded
beyond 128 Thus, a system of banks, with 128 sounds in each, has been created that enables manufacturers to overcome 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 resulting 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 result is a system of 128
banks that can contain 128 sub-banks in each
of them, which, in turn, can contain 128 sounds
(programs) within them
Bank change messages are useful when calling
up sounds from a large library that may exist in a
particular sound module or software synthesizer For
example, devices that are built according to Roland's
GS specification or Yamaha's XG specification
require you to specify a bank change in order to
access the extra voices that these devices provide
MIDI CC 0 is the bank select MSB (Most Significant
Byte) message This MIDI message is 7-bit in size
and can be used to select any of 128 banks This
message can be used in conjunction with MIDI CC
32 which is bank select LSB (Least Significant
Byte): a separate 7-bit message allowing additional
selection of any of another 128 sub-banks The
combination of Bank MSB and LSB messages gives
a 14-bit message that can select any of a possible
16,384 banks Each bank can in turn contain 128
possible sounds selected via a separate program
change MIDI message This enables a user to
theoretically recall over two million programs directly,
using only MIDI commands However, most devices
only use a few different banks, and you can often
ignore the LSB message