Looping Ambient Sounds

So I have this ambient sound that needs to be looped to work correctly. I ticked off “Do NOT loop” in the flags but to no avail. Help?

Is it a custom sound? In either case the solution probably is to add something called cue points. 5 sec Google search: http://developer.valvesoftware.com/wiki/Looping_a_Sound

Im guessing it will loop in-game and not in goldwave?

Yes. If you correctly add cuepoints and uncheck “Do NOT loop” it should loop in-game.

It works, thanks guys!