Thanks dudes

@chris: the player with this nice music data = 950 bytes, and that music use 4 patterns the max patterns could be 8 pat.
There's no big trick on byte usage, the player use 4 channel but I need to use 2 bytes for music data except when there's no note to play which in this case is one 1 byte. The first byte is the note and second byte have the sample to play and volume control.
The big trick here is to let the musician use their own music tracker, I'd provide the gm samples, the final file should be saved in .xm (fasttracker II format), and I use a special tool to convert back to my own format. This is really good, because we save a lot of time on music development and make the music artist happy

That's all, btw I can add directsound effects but not for now, I need to think a tiny and versatile way to use it.
Cheers,