Remove the case, clear every microphone opening, then compare a Voice Memos recording with front- and rear-camera video. A failure limited to one app points to permission or app support; failed recordings across apps point to service.
A call that sounds silent does not prove every iPhone microphone has failed. The phone uses different microphone openings for calls, speakerphone, video, and noise processing. Test them separately before resetting settings or booking a repair.
Remove anything that can block an opening
Take off the case, screen protector edge, magnetic mount, and any film left from installation. Inspect the openings without inserting pins, liquids, or compressed air. Brush away loose debris with a clean, dry, soft brush. Disconnect wired or Bluetooth audio so the iPhone cannot select another microphone.
Restart the phone and make a short call with speakerphone off, then on. Note which mode fails and whether the other person hears silence, very low volume, or distortion.
Make recordings that isolate the symptom
Open Voice Memos, speak toward the bottom of the iPhone, and play the result through the phone speaker. Then record a short video with the rear camera and another with the front camera while speaking normally. Listen with headphones as well if the speaker itself may be faulty.
Clear Voice Memos audio but bad sound in one calling app suggests an app, network, or permission issue rather than a universal hardware failure. If only one camera recording is bad, tell support exactly which camera was used. Save non-sensitive test clips until the case is resolved.
Check an app that alone cannot hear you
Go to Settings > Privacy & Security > Microphone and verify that the affected app is allowed. If the app is absent, trigger its recording or calling feature again and look for the permission request. Update the app and iOS. Do not disable organization management or privacy controls on a work phone without the administrator.
Know when testing is complete
The problem is resolved when new recordings and a test call are clear at a normal speaking distance. If all recordings remain silent or distorted after the openings are clear and iOS is current, contact Apple with the model, iOS version, failed test, accessories removed, and any liquid or impact history. Never send support a private conversation merely to demonstrate the fault.
Primary sources
Interfaces and policies change. We recheck the steps above against these sources and show the verification date at the top of the guide.