Just a side notice - if you select in some game in DosBox
Roland MT-32,
Roland Sound Canvas or any other Roland card as the option for music, without having the actual external sound module attached to your computer or without having at least an emulator for that type of music module, the music output in the game would be incorrect, and often even crappy compared to Soundblaster / Soundblaster Pro / Soundblaster 16 selection. The reason is because DosBox doesn't emulate those music modules.
You might want to simply select one of the
Sound Blaster options for music in that case, if you want the music being played as intended.
If you still want to use the Roland option(s), one possibility is to buy one of those sound modules on eBay, but they're usually heavy bid on and end up being sold for quite high prices. Another possibility, for example for Roland Sound Canvas, is to get
Virtual Sound Canvas (version 3.23 as only this one can run in Windows XP) which is an emulator for this sound module and does the emulation quite good.
For Roland MT-32 there're also emulators available, in my opinion the best is this one -
Link. But you'll need the two Mt-32 ROM files for it, which are not provided with the emulator.