I would explain it this way.  I hope it's helpful.

A "synth" (also called "synthesizer") is a hardware or software device that makes musical sounds according to the MIDI messages it receives.

Most synths have a variety of sounds available.  These sounds are called "patches".  The musician can choose the patch by sending a "program change" MIDI message to the synth.

The "program change" MIDI message can only select from among 128 patches.  Many synths have more than 128 patches available.  In order to accommodate more patches, they are organized into "banks".  The musician sends "bank select" MIDI messages to the synth, which prompts the synth to change to a different bank of patches.  Then a "program change" message can select a new patch within that bank.

Within Rosegarden, bank definitions specify the banks and patches available within a synth.  This allows the user to select a sound by name (e.g., "Trombone") rather than the series of numbers to be sent in "bank select" and "program change" MIDI messages.

On Wed, Jun 16, 2010 at 5:12 PM, D. Michael McIntyre <michael.mcintyre@rosegardenmusic.com> wrote:
Hey everybody...  This question requires a fairly long answer and I broke one
of my fingers at work.  Typing is not a pleasant process and I would like to
hand this question off for someone else to answer.


On Tuesday, June 15, 2010, 光宇董 wrote:

> by the way,could you explain some word to me?
> *<qt><p>Bank definitions allow you to tell Rosegarden about the programs or
> patches available for use on the equipment (hardware or software synth)
> connected to this device.</p><p>You must have something defined for any
> program or bank changes you wish to transmit, as Rosegarden hides all bank
> and program numbers that are undefined.</p></qt>*
> **
> *is "synth" a file that contains voice(such as piano)?   what's "define the
> bank"? is that tell the software that what voice the synth contains?*
> 2010/6/15 D. Michael McIntyre <michael.mcintyre@rosegardenmusic.com>

D. Michael McIntyre

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