Cloned Cube is a Portal mod. It takes place after GLaDOS' fall in Portal. You assume the role of Chell's secret clone. You have to escape or else you may just be tested to death. There is one obstacle. CUBiS is trying to kill you.
This is the loop that you hear from an open portal in game. My sister made it sound a little more musical. It sounds great in game except that it pops when it loops. I have to fix that!
The loop is popping in engine because the loop's end isn't silent like the beginning. If you want to stop popping you either have to fade out the sound to silence and make sure it loops in beat or make sure the loop's start appears at the end or vice-verca (same waveform content at start and end). Sorry for the techie overload but that's what's causing your problem.
If you use any DAW there is usually an option to wrap the end to the beginning.
I noticed something. Everything in Portal 2 plays Dubstep Music when it is turned on. And this fits right in.
I love it!