When talking on new iphone 6s, caller the other end sounds like they are a million miles away.I've done all the usual sound settings but still have the problem. Any ideas please
I had the same problem but when I called Apple Support and we tried a number of things - what fixed it was the plastic over the speaker hole. took it off and voila! Someone else did the same fix - don't discount it. At least try.
(taken from here https://discussions.apple.com/thread/6566555?tstart=0 )