Why does my microphone only work in camcorder and speakerphone?

[AC Question]

I have a Droid 2 Global and I think I am having a microphone(s) problem.

1. It works fine recording on the camcorder. Callers on the other end can only hear me when using the speakerphone (or headset).

2. It does not work for voice commands. Callers at the other end can't hear me when using the handset normally for calls. There are no screen protectors or cases.

3. Headphones with mic work fine both ways.

To try to isolate which microphone serves which service, I have tried holding my finger over the top mic, the bottom mic separately and at the same time. Camcorder and speakerphone both work when covering either or both microphones.

Are these mics dedicated to specific functions? If so, which one controls what? Any ideas on how to diagnose or fix would be appreciated.

Android ver. 2.3.4

 

[B. Diddy]

Welcome to Android Central! Where exactly are you locating the secondary microphone at the top of the phone? I'm just wondering if you're covering the correct opening when you're testing it. The behavior you describe makes it sound like the primary phone mic (the one at the bottom) has failed, while the secondary one is still working (which is why speakerphone and camcorder audio still works).

That phone is >6 years old -- wow!

 

[webosnationTEC]

The secondary mic that I am covering is a very small notch on the top/back of phone. Looking at the back of the phone, it is above and about 1/2" to the right of the camera lens. Actually, I put black tape over both mics and the headphone jack. Oddly, the camcorder and speaker phone both sound fine. Not sure how that is happening with both mics covered. And yes, it is an old phone. It is my secondary phone and the MVNO plan that I am using will not allow 4G phones.

 

[B. Diddy]

Tape probably isn't enough to completely block the mic from detecting sound, because the tape is probably acting as a sound-conducting membrane itself (like an eardrum). Use your finger to occlude the top mic, and see if people on speakerphone can hear you, or if the camcorder can still record audio.

 

[webosnationTEC]

I held my finger over the microphones in the first test and repeated it after your last post. Same thing. Camcorder and speakerphone both work. There is no difference in volume or clarity if my finger is covering the mic or not. Strange.

 

[B. Diddy]

Huh, that is weird. I wish I could find an official schematic of the phone on the web, but I've come up empty-handed so far. The closest I came was the iFixit teardown, which shows the secondary mic in the location that you're mentioning: https://www.ifixit.com/Teardown/Motorola+Droid+2+Teardown/3502

 

[webosnationTEC]

Thank you for the link for the teardown. It would be great to know if the problem is a bad lower mic. Do you know for sure if the top mic responds to the camcorder/speakerphone and the bottom mic is for voice commands/talking? If I can confirm this, I may just replace the bottom mic. It doesn't look that difficult to do. Again, thank you for your help.

 

[B. Diddy]

I think the top/secondary mic is conventionally the speakerphone mic, and also acts as one of the stereo mics for the camcorder. When you're on a call while not on speakerphone, it acts as a noise-cancelling mic. But I can't be sure that it's the case for all phones, sorry!