Microphone Damage

Hi Xcelsior2549,

Thank you for participating in the Apple Support Communities. We understand you'd like to know if recording a firecracker exploding could damage your iPhone microphone. This is highly unlikely but could theoretically be possible if the microphone's maximum sound pressure level rating is exceeded. If you're actually having an issue with your microphone now, this article has some steps that can help: If the microphones on your iPhone aren't working - Apple Support.

"If the sound is unclear during phone calls, during FaceTime calls, in video recordings, or in apps, learn what to do.

Clear the microphones

1. Remove any screen protectors, films, or cases from your iPhone.
2. Clear any debris from the openings of your iPhone. 

Contact Apple Support

If you still sound unclear during calls, recordings, or apps, contact Apple Support to discuss service options.

If you want to try more steps on your own

If you prefer, here are some more steps you can try on your own. You might still need to contact Apple Support after following these steps.

If people can't hear you on phone or FaceTime calls

1. Open the Voice Memos app. 
2. Tap the Record button , speak at the bottom of your phone, then stop the recording. 
3. When you play back the memo, you should hear your voice clearly.

If people can't hear you when you're using speakerphone 

1. Open the Camera app.
2. Record a video while speaking at the top of your iPhone.
3. Tap the camera chooser  to switch to the other camera. Then record another video while speaking at the top of your iPhone.
4. When you play back the videos, you should hear your voice clearly.

If the microphone doesn't work in a specific app

1. Go to Settings > Privacy > Microphone.
2. Make sure that the app is enabled.
3. If the app has permission to access your microphone, or if it isn't listed, contact the app developer."

Take care.