Background music and arpeggios when flying though the air...
I have no idea how, though.
I think what you are looking for was well explained by Neco at the "Mapping Tips and Useful Links" thread (http://forums.thinking.withportals.com/mapping-help/mapping-tips-and-useful-links-t468-15.html). As follows:
neco wrote:
Another useful thing I found out was to create your own 'rectangular' soundscape areas using trigger_multiples replacing the env_soundscape entities.
Create your own fade-in/fade-out logic_relays and let them trigger your desired sound files when 'start_touching' or 'end_touching' the area defined by the trigger_multiple.
The trigger_multiple method also has also the advantage to be exactly a large as the room if desired.
Hope that helps!
Skip to around 1:00 and listen when he jumps on the repulsion Gel.
Maybe that helps. I think I saw some other script also, but I can't find it right now.
