From the VSMSound documentation:
VDMSound is a program that overcomes what has probably been the most exasperating limitation of DOS boxes since Windows NT — sound support. VDMSound is an open, plug-in oriented platform that emulates an MPU-401 interface (for outputting high-quality MIDI music), a SoundBlaster compatible (SB16, SBPro 2, SB2, SBPro, etc.) implementation (for digital sound effects and FM/AdLib music), as well as a standard game-port interface (for playing games with joystick support). In development are improvements to the existing joystick emulation, and possibly VESA support.
Unlike all the Win9x SoundBlaster ISA ‘legacy’ drivers available from a variety of PCI soundcard manufacturers, VDMSound is not a mere ‘wrapper’ or ‘bridge’ to existing audio hardware. It is a self-contained, 100% software emulation program that is completely independent of your audio hardware type and settings. VDMSound works with any soundcard, and will even work on computers that have no audio hardware at all (for instance, instead of outputting sounds through your soundcard using the standard Windows drivers, VDMSound can easily output them to disk).