Wikipedia
DirectMusic
DirectMusic is a deprecated component of the Microsoft DirectX API that allows music and sound effects to be composed and played and provides flexible interactive control over the way they are played. Architecturally, DirectMusic is a high-level set of objects, built on top of DirectSound, that allow you to play sound and music without needing to get quite as low-level as DirectSound. DirectSound allows for the capture and playback of digital sound samples, whereas DirectMusic works with message-based musical data. Music can be synthesized either in hardware, in the Microsoft GS Wavetable SW Synth, or in a custom synthesizer.