Hi - love my iPhone 4 but I'm having an issue with the noise cancellation. When I'm on a call inside in a completely quiet room with a full signal and I start to walk around (really just a slow pace) people I talk to tell me that there is ridiculous background noise - like I'm outside on a windy day - to the point that they can't hear me. I can hear a really faint wind noise on my end but barely audible. As soon as I stop walking around there's no noise and people can hear me crystal clear (simple enough solution, I guess, but not really cool and I never had that issue with my 3GS). I've tried this with and without using a bumper but still same issue. Tried to cover the top mic, no change. Also, this does not happen when the phone is on speakerphone. And when I'm outside (and it actually is windy) the phone sounds pretty good too. I even tried this with my friend's iphone 4 and got the same behavior with his phone. Just wondering if other's have noticed this. Since I've seen the same issue on two iphone 4s, I'm not sure a replacement would solve it. Thanks and sorry if this has already been reported (didn't find a thread)!