iPhone 4 speaker crackle/distorted
A couple of days ago my iPhone 4's built-in speaker got this real bad crackling/distorted sound, it honestly sounds like the speaker is blown. The sound doesn't go away as I turn the volume down. This happened over night, I noticed it when my alarm went off in the morning. I do listen to music (usually Pandora) and watch YouTube videos, but it's never caused a problem in the year I've had it. Has anyone had this problem or have any idea about what I should do? I live about 2hrs from the nearest Apple Store so I can't just make a quick trip.
iPhone 4, iOS 5.0.1