http://www.somascape.org/midi/tech/spec.html#banksel
For FluidSynth,
Interpretation of MSB and LSB depends on synth.midi-bank-select
https://github.com/FluidSynth/fluidsynth/wiki/FluidFeatures
synth.midi-bank-select Type: Selection (str) Options: gs, gm, xg, mma Default: gs This setting defines how the synthesizer interprets Bank Select messages.
gs: (default) CC0 becomes the bank number, CC32 is ignored.
gm: ignores CC0 and CC32 messages.
xg: if CC0<120 then channel is set to melodic and CC32 is the bank number. If CC0>=120 then channel is set to drum and the bank number is set to 128 (CC32 is ignored).
mma: bank is calculated as CC0*128+CC32.