First of all stop getting high its bad for your health you know

Second of all i did not read the topic
Third here is a simpler way to make the music loop and actually make a turn on/off system(what no one bothered to answer or what i didn't bother to read

)
Here it is:
Condition:Player X brings at least 1 anyunit to location 'musicon'
Actions:play Wav (corboandhisguitarpwnsall.wav)
Wait(wav length)
Preserve trigger
now to answer your question you will have to do what i just said and add some conditions like elapsed time or switches example
Wav 1 (switch 1) when it stops set new switch and stop the old one just like it and in the last trigger you want preserved you don't clear the switch
as simple as that, when you get your unit out of the location the music will not play again however it will not immidiately stop it (you know you can't stop music)
using a bring action has always saved me a few switches and a lot of work keep that in mind oh and keep in mind that using a wait time like this will mess up other waits so do this trigger for each player you want to play the music for