I'm having the same initial problem as Burge with DOTT. To start with everything works fine (opening sequences and first cut scenes) but as soon as I actually start to play voices and sound effects disappear never - so far at least - to return.
The replies to Burge's original post are no help to me. Could anyone tell me if there is a solution to this. I don't want to appear ungrateful but I thought the whole point of Scummvm, Q+E etc was to do away with the lack of sound when playing these games under Win2X etc. So far this hasn't been the case for me (except for Samnmax) which is a little frustrating to say the least.
Any help will be gratefully received.

The floppy version of DOTT only has voices in the intro so that may be why. As for sound effects I dont know, perhaps its related to the problems with MI you mention in your other thread.