Audio macro for Twine version 1
Not sure where I found this code, sorry. Will give proper credit when I figure it out.

<<playsound "sfx1.mp3">>
Use playsound to simply play a sound once.

<<loopsound "track1.mp3">><<loopsound "track2.mp3">><<loopsound "track3.mp3">>
Use loopsound to loop background music.
You can split it into tracks, like bass, guitar, drums. If the tracks are the same length, they will remain in sync.

<<mutesound "track2.mp3">><<mutesound "track3.mp3">>
You can mute a looping track. For example, I have muted the guitar and drums, but I'm letting the bass play.

<<unmutesound "track2.mp3">>
Unmute a looping track. If the tracks are the same length, they will remain in sync.