I've been noticing, it's happened probably 4-5 times in the last week or so, that when I'm on my phone at home, I get this weird crackle. The only way to describe it is like when you have a headset plugged in and you move the jack that plugs in around and it creates that crackle sound. Yet nothing is plugged in. It seems to be more prevalent when I make the call but I think it's happened on inbound calls as well. I have 3 of 5 circles for signal strength (AT&T). Whenever it happens, the other person doesn't seem to hear it. I did some searching and saw a good bit of this issue back on the iPhone 4 but didn't see much with this phone. Any ideas what might be causing this?