So my late 13" is at the Apple Store right now (oh my goodness they're taking forever) to replace the Left speaker. The reason for sending it in was because of some faint crackling distortion in the speaker after the volume was put at least half way. Especially with higher frequency sounds. Is this something that happens to all the unibodies? Or is it just mine in particular. Did I waste my time sending it in? We'll see in the next few days. I was just wondering if anyone else had the same problem as I do.