Mic broken on Android phone... except the mic works?!

June 17, 2020 12:45 PM

My phone has no sound on phone calls, but the mic does not appear to be broken.

I have a Motorola Moto e5 Play, running Android 8.0.0. Some weeks ago, the screen showed a fault: there were lines and streaks on the screen. My local phone repair shop replaced the screen for me.

After the repair, I noticed that my microphone did not work on phone calls. During a phone call, on either speaker-phone or in regular mode, nobody could hear my voice. Using a headset, however, people could hear me. "Dang it!", I said to myself, "the phone repair guy broke my microphone!"

But when I took the phone to the phone repair shop, the repair guy pointed out that the microphone seemed to be working. You can take a video on the phone, with sound working correctly.

The obvious implication is that the microphone for phone calls was broken while the mic for videos was not. But I can't find any evidence that there are two mics in the Moto e5 Play.

- All the sources on the web, that I can find, refer to only one mic.
- There is only one opening in the case for a mic.
- Taking the back off the phone reveals no obvious second mic.

Videos record with sound. Phone calls do not. WhatsApp phone calls have no sound.

How is it possible that the microphone works for some apps but not for others? Can I fix this?

posted by jb to Technology (7 answers total)

I had an older phone do something similar when it decided that crud in the USB port meant it was plugged into a car kit dock, and started answering every call in speakerphone mode at maximum volume. I suspect this is something similar, where it thinks you are using a dock or a (wired) headset and is defaulting calls to that phantom mic instead. I can see where this would affect phone use but not video recording. The damage to the phone might be worse than was detected, like a hairline crack or tiny short in the circuit board is misleading the sensor that judges this.
posted by CyberSlug Labs at 1:59 PM on June 17, 2020

It could also be something sensing there is a mic plugged into the headphone plug, when there actually isn't. Sometimes this can be fixed by plugging/unplugging a headphone cable a few times, or other ways that you can perhaps google.

Also I can tell you from poking around in the Android programming innards a year or so ago, that the programming path for routing microphone audio to a phone call, and for routing microphone audio to literally everything else on the phone--such as video recording, audio recording, maybe even apps that "act like" a phone call such as Zoom or Skype--are wildly and completely different from each other.

So it doesn't surprise me at all that the microphone could be completely broken for phone calls yet completely operational for everything else. The code and processing and everything else for phone call audio and every other kind of audio is completely different.

FYI this seems to be part of an effort to reduce lag on phone calls that came into place in a fairly recent version of Android (maybe Android version 7, 8 or, 9? Somewhere in that time frame, anyway).

I don't know if this leads to any particular solutions to your problem, but the idea that it *could* be a problem is no surprising at all to me.

If all else fails, I would be thinking about something like a complete factory reset and reinstall of all software. Not guaranteed to help but maybe--again, if you've tried everything else and the situation is not improved. Be aware that this will erase everything on the phone, so make all necessary backups first.
posted by flug at 5:19 PM on June 17, 2020

Have you rebooted the phone?
posted by Kirth Gerson at 6:23 PM on June 17, 2020

I had a weird similar problem a few years ago, where my Android phone mic didn't work properly on phone calls only. (It DID work intermittently, but fuzzily, and other times it didn't work at all, but only ever on phone calls). Maybe it's not the same problem but just in case, for whatever reason, disabling the "Ok Google" thing where the phone listens for your voice solved it. You can do that somewhere in the settings. It was some weird interaction between the microphone being in assistant listening mode vs in conveying sound to the person on the phone mode or something, and for some reason was triggered by phone calls. I know that doesn't make a ton of sense - I only have a fuzzy memory of what the mechanics of the issues were, but I do know that disabling the assistant worked.
posted by lollusc at 7:19 PM on June 17, 2020

I would check if it behaves differently on speakerphone or with a headset. Agree with flug above that it's worth trying a factory reset if that's feasible, but circumstantially I would strongly suspect that the "phone handset" mic connection got bonked during the screen replacement, and this could be different hardware from the speakerphone/video mic. EDIT: oh wait you said speakerphone, sorry. Still worth checking a headset though.
posted by implied_otter at 9:32 PM on June 17, 2020

I dunno if your phone has two mics. However, I would get "contact cleaner" spray and give it a spray. I had a similar issue with my speaker. Speaker worked for music and speaker phone but not for phone calls. In this case it was obviously different speakers. When my charging port broke someone suggested contact cleaner spray. When I sprayed the charging port I figured no harm trying the speaker at the same time. Speaker and port both fixed.
posted by If only I had a penguin... at 2:25 PM on June 18, 2020

This review has pictures that appear to show holes for two microphones. One is on the bottom near the charge port and the other is on the top near the headphone jack. With smartphones, normally the top microphone is used for noise cancellation purposes during a phone call, since it hears much less of your voice than the bottom microphone and can be used to somewhat isolate ambient noises and cancel them. I can see a situation where the phone switches to the top microphone for video, or maybe uses both microphones for L/R channel sound. If that were the case, then it's possible that they broke the bottom microphone but the top one still works. It would be a potentially interesting experiment to record a video and then listen to it with headphones to see if one channel is much quieter than the other. If so, I think that points to evidence that the top mic is OK and the bottom one isn't. Having said that, if the L & R channels on a video sound fine, I don't know that would prove anything, because I don't know that they would really use one for L and one for R during video recording (that was just a wild guess).
posted by Quiscale at 3:02 PM on June 18, 2020