Chosen Solution
I happen to have this very strange problem with my phone. The microphone works perfectly fine when I talk on the phone, even while I change to speaker during phone calls and when I do recordings with the Voice Memo as well. I make Whatsapp, Viber, FacebookMessenger calls too and there is nothing wrong with it. However, only with making phone calls using the mentioned apps, whenever i change to speaker, the other end tells me that they can hardly hear my voice. The microphone barely catches my voice even if the phone is close to my mouth. I have tried resetting my phone, deleting the apps and reinstalling them but the problem is still there. Again, this doesn’t happen with regular phone calls, both in and out microphones work fine. I have never been more frustrated. Does anyone know a solution or perhaps have tips for me?
Prior to the 6S, the speakerphone microphone in normal (not Whatsapp) calls is the one in the earpiece grille attached to the proximity sensor. Starting with the 6S, they started using the redundant in-call mics by the charge port to complement the top mic. Which microphones Whatsapp chooses to use is unknown to me as I don’t use it on customer devices. Make sure you don’t have any debris blocking the holes at the bottom flanking the charge port. Barring liquid damage, I’d be surprised to see either the earpiece microphone or the charge port microphones to “go bad” at this age. If your issue is a hardware one, your top suspects are the charge port flex or the sensor (AKA front camera, proximity sensor) flex since they contain the bulk of your microphones.
