They may cause you to better perceive Tinnitus , and decreased hearing. I had an on and off high-pitched ringing in my ear for a week and a half, which then crescendoed yesterday with my 5th straight day of ringing and forced a visit to the doctor. It turns out I had about a tic-tac box's worth of wax completely plugging the canal. They flushed my canal with some saline solution and the improvement was dramatic. A subjective measurement would say my hearing improved three-fold, and following the initial cleaning session (1 of 3) her voice sounded as if it had been turned up to 11. The cause? The doctor nor I could be completely sure, but she believed it to be the headphones(Shure e3c). It makes sense. Qtips are not to be used to clean ears because the head actually shoves the wax deeper into the canal. The little cushions on the headphones most likely caused a build-up via a similar mechanism. By shoving the phones into my ear, I also shoved a wax build-up (caused by the phones) deeper into my canal, which after time led to a complete blockage. Now this is of course not a problem with everybody, but if using them or considering buying them I would suggest you keep your ears cleaned.