Is your feature request related to a problem? Please describe.
There are many MIDI instruments that sound extremely similar to each-other and really don't warrant separate instruments in MIMI (I.E: There are like 4 different bass guitar sounds) but would be nice to have access to.

Describe the solution you'd like
It would be cool to either be able to switch between different voices of an instrument from the GUI or perhaps by placing the instrument in a crafting grid in the same way that you switch between stone variants in vanilla.

Describe alternatives you've considered
N/A

Additional context
N/A