Midi Messages In-Depth; Program & Bank Changes - M-Audio Session KeyStudio User Manual

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Table of Contents

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 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 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.

You will ﬁnd many MIDI devices respond to program change commands and many are organized according to the GM listing. In General MIDI

devices, different sounds are organized in the same way from device to device. Piano sounds are in their particular place, string sounds are in

their place, drum sounds are in their place, and so on. All GM devices (both hardware and software sound modules) are clearly labeled as such,

so you know that their sounds are organized in the General MIDI structure. When a GM device receives a MIDI program change, it calls up a

type of sound that you expect from the GM sound set. All non-GM MIDI sound modules call up unique sounds from their memory upon receiving

MIDI program changes. Since the sounds in a non-GM device are not arranged in a particular order, you need to take a look at the device itself

to see which sound you want and at which location in the memory it resides. Many VST instruments such as Native Instruments' FM7 or the synth

modules in Propellerhead Reason are non-GM devices.

You can send program change, bank LSB and bank MSB messages directly from the KeyStudio keyboard. Please consult the "Advanced

KeyStudio Features in Edit Mode" section of this User Guide for further details.

Session KeyStudio User Guide