So... My version of Ultima doesn't have music, and I'm pretty sure the official Apple ][ version had no music without a sound thingy... uh, I don't know. Anyway, is there a way to mod in the Ultima 4 soundtrack without ux4?

See the sticky thread for the unofficial Ultima IV upgrade patch. Also comes with a nicer VGA tileset. i don't know if you can have only the music without the graphics upgrade though, if that's important to you. Personally I like the new tileset much better than the original graphics.

use the media player of your choice to play medieval music or the later soundtracks.

Well, you could download a C64 emulator and then find the C64 version of Ultima IV, it had music!

the closest you will get is using the xu4 source port/fan engine, it will allow you to play the game in EGA with music, it's quite faithful and any additional stuff they may have added can be turned on or off. Outside of that you could try the old Midi patch but that is not recommended since it was never completed since the creator of the patch merged the project with the VGA patch project. So the music sounds like ass as it plays way to slow.