원문 게시자: [deleted] ,
The audio from your Hands Free device is being picked up by the microphone in that device and being sent to the phone via radio (bluetooth) which explains why it works and the built in microphone doesn't. The electret microphone in the phone is very small, usually less than 4 mm in diameter. Likewise the hole in the case to let in the sound. The hole is about 1 mm. In the case of muffled audio, it is possible that a small particle lodged in the hole and is partially blocking the sound pressure from reaching the microphone. It might be possible to very carefully remove a particle from the hole using a straight pin. DO NOT push the pin into the hole. You WILL damage the microphone. Replacing the microphone is not a typical DIY task. Unless you have superior soldering skills and soldering equipment designed for working on Surface Mount Devices (SMD), I guarantee you will fail at replacing the microphone. Which leaves you with two choices: Replace the whole phone or use it only with a bluetooth microphone.