I have found a solution how to fix the calling noise on your Iphone!
I had exactly thesame problem and it drived me nuts!
Somehow I discovered when you make a pressure on you Iphone where the speaker and the mic goes the odd buzzing noise disappears at your gsm calls!
My solution to this was that something
got lose with time and therefore it vibrates
when there was a tension in the circuit.( That was
only my theory)!!!
You can fix this problem without replacing or repairing
your Iphone, you just have to open up your Iphone,
and put a little bit of rubber above the speakers and the mic( I used half the lengt of a keboard tangent). You can go to youtube and see how you can open your Iphone, I can assure you that it will not break, I have opened mine about 5 times now, to correct the rubber so the noise will be gone. I used a smal rubber so when I putted the display back it would only maby be a gap at 0.5mm maby even less!
Note: Peoble at youtube opened their Iphones with somking of stick plug, I used two needles that I poked into the wholes where the screws goes and like ben it up. Hard to
eplain, but if you look carefully at the screw wholes you will see that the other part will
move with the display, and you can push that part up with your needles!
Note: If your home button stops to work, don’t be worried, you have just used to
thick rubber(that you will have to slim down) so the Home button cannot make contact inside the phone, you will notice this when you open your phone, that the home button from the other side of
display makes a contact with two small pins inside the phone when the display closes.
I hope this will work for you too!!!