I was wondering about the music from the EE too. It does seem to be different from the classic version - why is that?
I haven't tried the classic version, but I am assuming it is the DOS version (or SSP). However, it most probably uses FM synthesis per default (sound blaster, OPL3). This is probably what some / most people remember.
You can get (mostly) identical music from the classic version if you enable GM midi music (not sure if the required files are included or not). What matters then, is only the soundfont / hw synthesizer you are using. So: the music is identical, it's only that the enhanced edition does not have FM chip emulation.