If you have a slower computer (although i'm extremely reluctant to call my P4@2.8GHz "slower", it's a fact that my work computer with a Core2 just feels that much snappier) and want to play DOS games in dosbox, you might experience this:
The overall game performance is good, your CPU is not even fully taxed, sounds generally work as expected - all nice and fun, except for the MIDI music. Which crackles and skips and stutters and is generally unpleasant enough that you want to turn it off.
Fear not, for i have found a cure!
Open your dosbox.conf (you don't have one? head over to google and find yourself a nice set of instructions on how to create it and where to place it), locate the [mixer] section and increase the prebuffer value. I set mine to 50 (default seems to be 10) and the music is smooth like a cleanly polished watermelon. Or something.