What the hell? I've used T-Mobile, Verizon and Sprint. But only AT&T makes buzzing noises on my speakers at home and and work. And it's not just me, my friends (without iPhones) say the same thing. Since I have an iPhone, I have to use it near my computer (to sync it)! I think I need a 10' sync cable to keep it away from my Bose speakers otherwise it sounds like a redneck with an amped up 1978 Cobra CB radio is sitting in my driveway chatting up the "eager beavers" and warning the "gypsies" about the "rolling bears". Grrrr!