Released September 25, 2015. Model A1688/A1633. Repair of this device is similar to previous generations, requiring screwdrivers and prying tools. Available as GSM or CDMA / 16, 64, or 128 GB / Silver, Gold, Space Gray, or Rose Gold options.

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Sound up & down when recording video


I noticed that the sound volume of any recorded video in my iPhone 6s starts low and then increases/ decreases with no obvious reason.

The sound result is like switching microphones front/rear, however I am not an expert and this is just a wild guess to describe how it feels like.

When I play the video in my computer, the sound issue is still there, so it should be a microphone hardware or software issue?

I haven't exposed the phone in any humidity sources nor having dropped it.

For the record I have tried to tackle the above issue by:

- testing the iPhone's stock camera app vs. other video recording apps and the issue persists.

- restoring and set up as new

- resetting options etc

with no good results.

Answered! View the answer I have this problem too

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4 Answers

Chosen Solution

There are 3 microphones in the iPhone.

  • The bottom microphone is for Voice Memo and phone calls. The other microphones serve as error cancellation
  • The (top) front microphone is used for FaceTime calls, Siri and selfie videos with the front camera (FCAM). The top back microphone serves as error cancellation
  • The (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. 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.

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Thanks for your quick reply!

Could you please inform me if you know any app that tests the individual microphones?


I don't know of any diagnostic app (perhaps others can chime in), if that's what you mean. Just run the apps I highlighted above to test each microphone. Make recordings or calls to voicemail and play them back. Don't forget to test the headphone microphone also.


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I am having the same problem. But I used my memo app and test the audio and it doesn’t seem to happen when using the memo application... but I don’t understand why when I use the camera the problem persists

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This problem only happens when I record video. Not voice memos and it only recently started happening, maybe 6-7 months ago. That is a LOT of audio editing post filming. It is clearly switching mics as the sound is loud then soft then loud with zero consistancy. I have tried covering the mic(s) and it still doesn’t work properly. At $1000 a phone, I am not willing to run out and purchase a new one when it seems it was an update that caused this to start occurring. It seems the giant has found another way to force users to buy new products. Also, I am a lefty. Read some stuff on that but I don’t think that has anything to do with it. ??

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I am having the same issue with my iPhone 8. Only when recording in the selfie mode does the phone volume goes in and out. It is clear one second and the next it’s muffled and significantly lower. I used selfie mode in Snapchat and no problem. I used the voice recorder on the voice memo, no problem. The problem only occurs when recording directly to iPhone library. Did you find an answer?


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I have the same problem. No problem in voice memo but In video the sound comes and goes

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