Then you did something wrong.
Not 'a' soundcard, SB original for music and effects.
Also hit the 'configure' button, and set params properly for music AND effects.
Works fine for me, really, default dosbox config file, nothing altered.
Did you correctly unpacked? You should have some 123 files in you game dir.
Maybe you would better delete the game folder and start over from scratch, can help.
[Edit]
There you'll find the two config files for MoM in dosbox 0.72.
Overwrite the old ones.
http://www.abandonia.com/vbullet/showthread.php?t=17514
Should you still have problems, reply there and give ALL your mount lines, fully detailed please.