I am become sorcerer, thanks for the base file. Updated it so it shows only the song defined as music, and only stops when said song stops or a new one starts playing. Won't show any sound effects, though.
Also, going by what little I understood of the one other file I opened, apparently you can define sound effects to loop until you tell them to stop, like music, and more than one channel for sounds too, I think, but that seems like high level renpy.
EDIT: Backscrolling support added, no promises it won't break if Sel does something.
EDIT 2: Electric Boogalooing into your settings, because I realized it'd show in screenshots and at least I didn't want it.
EDIT 3: Silent edit because apparently something breaks even when it's a default, also I didn't know you could global like that. The second, less heavy, file is the new one, leaving the old one just in case someone understands what's happening.