Very odd sound issue with Late 2007 Macbook Pro

Hey all, I would appreciate any help possible, as this issue has been driving me crazy. About two months ago, my Macbook Pro speakers began to crackle a little bit. This happened simultaneously, and with low volume so I really don't think I blew them. When I play a song in itunes to my wireless speakers by selecting the speakers in iTunes, everything sounds fine. On the other hand, if I play the same song in iTunes, and set my audio output within iTunes to my built in speakers, and then use AirFoil to stream that signal, the same crackle appears. The sound will sporadically get very low, and all I can hear is the crackle. This odd AirFoil predicament leads me to think it may be some sort of driver issue. Anyone with more knowledge able to lend a hand? I really appreciate the help. - Aaron

Just bumping this in the hope that someone may see it and be able to help, if this isn't allowed my apologies.

Have you disabled Airfoil and just played music with your built in speakers without any alteration? Sounds similar to a problem I've seen with some computers that have Realtek installed when the settings assume you have giant speakers that can handle very loud output.

Hey FasterPussyCat, thank you for the reply! The problem shows up whether I'm using airfoil or not :-/ And it's not just iTunes, it's anything with sound. For example, watching youtube videos will cause the crackle, even without airfoil enabled. Sorry if that's not very helpful, let me know if there's anything else I could tell you that may help. Thank you so much!

The crackle is most likely caused by a faulty speaker in your MBP. Since you can stream the music to your wireless speakers and get clear sound, drivers and the sound module in your machine are probably OK.

If your MBP is still under warranty you might want to take it to Apple and let them change out the bad speaker. I guess it could be both, but probably just one.

Regards.

Thanks for the reply chscag! It's out of warranty, as I unfortunately do not have Applecare coverage :-(

To clarify, why would the busted speaker cause crackling on my external speaker through airfoil? Sorry if I'm being annoying, I just am trying to understand this problem :-(