I noticed than the game takes a long time to load, I'm pretty sure it's because the music files are loaded into memory at startup.
To do it quick, "static" sound files are loaded and decompressed in memory where "streamed" sound files are directly read from the disc.
The advantage of "static" files is than they are really light process to read, it is recommended for SFXs and other short sounds.
Music files on the other hand should be streamed.
Hope it helps you :)