Here's a quick solution for those who have the following problem on iPhone 6 (I assume it works on other models as well)
NOT WORKING:
- Siri works, but she can't hear you
- Dictation can't hear you
- Front-facing camera records only background static in video mode
- Instagram's front-facing camera does the same as above
- When making a call, people can't hear you when on speaker mode
WORKING:
- Snapchat video records sound normally, front- and back cameras
- Voice control works
- Voice memos record normally
The first thing you should do is check whether all 3 microphones on your phone are functioning. The Voice memo app should take care of the bottom mic. Use the native Camera app to test out the remaining two. While recording video with the rear camera, give the little pinhole next to the lens a few firm taps with your fingers. Do the same with the front camera, tapping on the left-most corner of your receiver speaker. If the mics are working properly, you should hear a considerably loud thud when playing back the video. If the thud is faint or almost indiscernible, you probably have a dirty microphone. If there is absolutely no sound at all (be sure to do a very thorough check, if need be, scream loudly into the mic at point blank range), the mic will probably need replacing.
Buy a can of compressed air and carefully blow into the microphone ports meintioned above. It doesn't hurt to clean out the rest of the ports either.
This worked for me. I have no idea how I got crud in there and I only noticed it after Siri stopped working abruptly.
Again, if there is even the faintest sound while testing out the mics, this is not a software issue.
Hope this helps. Cheers.
