After a phone gets wet, most people check the speaker. The microphone is easy to forget until someone on a call says you sound like you are underwater. Microphones trap water too, and they need different handling.
Why the eject sound will not fix a microphone
A speaker can clear itself because it moves. Its diaphragm pushes air out through the mesh and takes the water with it. A microphone only listens. It has a tiny membrane that responds to sound but cannot push anything. Playing a tone does nothing for the mic directly.
There is one partial exception. On many phones the bottom microphone sits next to the main speaker. A strong eject tone shakes the whole lower edge of the phone and can help loosen droplets nearby. It is worth one or two runs, but do not expect it to do the whole job.
Find your microphones
Most phones have two or three:
- Bottom mic: a small hole beside the charging port. Used for calls.
- Top mic: a pinhole on the top edge or in the earpiece. Used for noise cancelling and speakerphone.
- Rear mic: a pinhole near the camera. Used when recording video.
Test each one
- Bottom mic: record a voice memo and play it back.
- Top or front mic: record a selfie video and talk.
- Rear mic: record a video with the back camera and talk.
Whichever recording sounds dull or distant tells you which microphone is blocked.
How to dry a microphone
- Point the hole downward and tap the phone gently against your palm.
- Touch a corner of a dry tissue or lint-free cloth to the hole. Just touch it. The tissue wicks water out by itself. Do not push it in.
- Leave the phone in moving air with the mic hole facing down for a few hours. A fan helps a great deal.
- Test again with a voice memo.
Never put anything in the hole
The microphone membrane sits a millimetre or two behind the opening. A pin, a SIM tool or a toothpick will puncture it, and a punctured mic cannot be repaired, only replaced. Many people have destroyed a microphone by mistaking the mic hole for the SIM eject hole. Compressed air can burst the membrane in the same way.
If it is still muffled
- Check the case. Some cases sit slightly off and cover a mic hole.
- Check for residue. After salt water or a sugary drink, wipe the area with a barely damp cloth and dry it again.
- Check Bluetooth. If the phone is connected to earbuds, it may be using their microphone.
- Restart the phone. A stuck audio process can make a working mic sound wrong.
If one recording is still dull after a day of drying, that microphone has probably failed. It is usually a small, inexpensive part to replace.