dosbox has a mixer tool (for all soundcards and cd audio too) which might be good enough:
MT32 is a different channel from Soundblaster so i'm probably sorted.
MIXER SB 50
allows me to lower the voice to 50% of the normal, but not music (and other sound effects unfortunately but ce la vie). Also the sound scale doesn't seem to be linear, i put it to 10% and it only sounded slightly muffled, so i guess i'll end up to about 50-60% to just remove the outrageous high (i guess they wanted it to be higher than the music all the time without hacking the exe, but this was a bad move imo).
to use different sound cards for music you first check out the monkey.exe comand line options, running it once with
will show them. The voices always seem to run through soundblaster so for me
works for roland + soundblaster ... somehow.
One thing i noticed, the ultimate talkie monkey island 2 is not saving the voice+text settings yet, is this intentional?