M-Audio 25 manual Midi Messages In-Depth, Program & Bank Changes

KeyRig 25 User Guide 17

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 programs + program “0” = 128
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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
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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.
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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		���������
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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-		���������
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banks in each of them, which, in turn, can contain ����������
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128 sounds (programs) within them.		�����������
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Bank change messages are useful when calling		���������
up sounds from a large library that may exist in a		���������
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particular sound module or software synth. For	������������
example devices that are built with Roland’s GS		�����������
specification or Yamaha’s XG specification require
you to specify a bank change in order to access the
extra voices and effects 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
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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 allow you to access them with either a Bank LSB message or a Bank MSB message. Please consult your synthesizer’s or software’s documentation for more information on which type of bank change messages they can process.”