My Droid Turbo (Android v.4.4.4) has developed a problem. When I make calls nobody can hear me, but as soon as I hit the speakerphone button everything is fine. I'd take the phone back to Verizon for a replacement, but it's the same microphone in both situations, right? So how could it be a hardware problem? Is there maybe a volume setting somewhere I need to tweak?
Lots of phones have more than one microphone on them. I know for a fact that my Oneplus One has three, and I think your phone has four. If that's the case then it could be a hardware issue. before taking it back do a full reset and see whether that helps. At least then that eliminates the possibility of a software error.