Hi all, Had my iPhone 3G since July and lately I have been using speakerphone a lot to make calls. Nevertheless, people have been complaining that they can't hear me - that my voice comes and goes during a conversation. Normally I make these calls at my home and always have 4 or 5 bars of service. After restoring my phone, I still have this problem. What's more confusing is that Shazam works perfectly, so the mic seems to be working... Anyone else experiencing this problem. Is it likely just the cell network?