Music change in levels

[Super mystic sonic]

Ya know, I've been thinking this for a while, and I couldn't find it anywhere either. If its on the SRB2 wiki, forgive me that I didn't take the time to look everything trough.

Okay, so the question is, I've seen numerous wads that change music when you enter certain sectors. The question is, how do I make music changing sectors?

 

[BlueZero4]

Some random linedef executor. Go fishing.
Edit: This one.

 

[Super mystic sonic]

How could I've missed that? I even looked at the lindef executors!

Thanks, by the way.