DOSMid is a MIDI and MUS player for DOS. It's a real mode application designed to run on very modest hardware configurations. It plays standard MIDI files, as well as MIDI in RIFF (ie. RMID), and MUS tunes (as used by Id Software in numerous games like Doom, Heretic, Hexen, etc).

DOSMid requires a MIDI-capable hardware available either via the standard MPU-401 interface, or an RS-232 port, or an EMU8000 engine (as found on SoundBlaster 32/64 AWE series). Note, that some sound cards provide an MPU-401 interface natively, although many need an additional 'wavetable' daughterboard to produce actual MIDI sound. Since DOSMid v0.7 it is also possible to somewhat emulate MIDI via FM synthesis using an OPL chip (that is one of the Yamaha YM3812 or YMF262 chips, found on most sound cards from the nineties) - be warned however that, most of the time, such MIDI-over-OPL emulation will yeld less than desirable results, unless the MIDI file was specifically crafted for OPL.

Official website can be found HERE