in Spawner v1.1 you can add music of a lot of ways... one of this ways is the next:
in this folder(fmod/MAPS), copy/paste you music and re-write with the name of the map...
for example... i like the music "Matrix"(matrix.mp3)... then i copy this music and paste in the folder Maps (in the folder fmod), then i re-write the file "matrix.mp3" for the next: "Smallone.mp3"... now when you start the map smallone the matrix music will automatic play 

enjoy! :D