INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SET LEFT/RIGHT BALANCE                
	AX = 6904h
	BX = voice number (00h-1Fh)
	CX = balance (0 = left, 7 = even, 15 = right)
Return: nothing
SeeAlso: AX=6902h,AX=6903h