Chosen Solution
I search everything to find someone with a problem similar to mine but could not find it. My iPhone frontal mic does not work for most of the time, but I managed to make it work sometimes, here’s how: I make a call and before I hear the first dial tone I press the speaker option (which uses the top frontal mic) and on the other end people can actually hear me (which may seem that my mic is working well), but if I decide to turn off speaker mode and turn it on again, the mic will not work at all. Facetime, Siri, Front Camera recording does not recognize my voice at all. Anyone have a clue why the microphone would have this kind of erratic behavior?
There are 3 microphones in the iPhone. https://support.apple.com/en-us/HT203792 The bottom microphone is for Voice Memo and phone calls. The other microphones serve as error cancellationThe (top) front microphone is used for FaceTime calls, Siri and selfie videos with the front camera (FCAM). The top back microphone serves as error cancellationThe (top) back microphone is used for videos with the rear camera (RCAM). The top front microphone serves as error cancellation Make sure you update your device to the latest version of iOS and then try to isolate which microphone is not working properly by trying each individual microphone with the related apps above. Check the microphone port holes for dust and debris which could be attenuating the sound. If the issue affects more than one microphone, then it could be the Audio Codec IC on the logic board. Anything at the logic board level will require micro-soldering so you would need to find a repair shop that offers those services.
