Wait and install iOS 5 when Apple releases it to the public. If it still gives you problems. I would say you have a hardware issue.17" 2.2GHz i7 Quad-Core MacBook Pro 8G RAM 750G HD + OCZ Vertex 3 SSD Boot HD
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I have this on my Verizon iPhone 4. After installing iOS 5 GM, sounds are pretty much all but gone, occasionally I'll get the charger plugged in tone. Also while using headphones it may stop too while playing music. Downgraded back to iOS 4 and it was fine again. I just knew iOS 5 was not ready for the public and most likely won't be on the 12th.