I bought SMAC-PP and I don't hear the game music while playing
I used to play a demo of the game, here I didn't have any problems with the music tunes. but now, whenever a special event affects the music (base founded, e.g.) or just the background music is supposed to play, only the FIRST TUNE (first wave file of the 'track') is played. and then, silence
Since your getting music when running smacx, I can't see what the problem is. There's a lot of stuff in smacx which does improve gameplay, although some would say the original is a better game.
If your concerned, have you checked to see if in 'options' if music is disabled?