One of the biggest problems with heading into a rehearsal as a keyboard player is picking which sounds (patches) to use. I've too-often spent many hours meticulously programming the exact sounds I think I should use, only to completely abandon them when the MD changes musical direction in rehearsal. Here's some simple do's and don'ts when trying to get the sound you want onstage:
• Make sure you have a bunch of solid "stock" sounds available to select at any moment (i.e. simple atmospheric pad, piano, organ, etc). That way, if the sound that you programmed doesn't work, you can quickly switch to a more generic sound that might be a better fit.
• Take notes. If there's something you need to fix in your patches, make a note of it during the rehearsal.
• Check your levels beforehand. Custom-programmed keyboard sounds have a reputation for being all over the place when it comes to volume- a simple VU meter can give you all the info you need at home to know if you're going to be too loud or too soft. (Also, make sure to check that all your patches are peaking at around the same level, too).
• Program sounds at the rehearsal. There's nothing that other musicians hate more than having the rehearsal screech to a halt while you dial in the exact sound that you want. Make a note of what you want patch-wise, select a more generic sound, and keep playing. No one will probably notice, anyway.
• Pick patches that will overtax the CPU in your computer (if you're using a computer). There's nothing worse than crashing your live sound program by using a plugin live that requires too much power. Stick with stable, time-tested plugins that don't take up too much CPU when playing live.
• Arrive at the same time as the other musicians. Get there early, so you have a chance to sound check each of your sounds through the monitors. Many times, you can head off problems by simply hearing what your patches sound like in the practice space before any of the other musicians get there.