There are multiple microphones on your phone, so we need to know which one you're talking about. There's the lower one used when you're on a phone call, and the upper one when you are on speakerphone or recording a video. Which one is giving you problems?
Have you tried cleaning the microphone port? Some isopropyl alcohol and a soft brush often helps if the hole is gummed up.
1 
Hi Philip,
There are multiple microphones on your phone, so we need to know which one you're talking about. There's the lower one used when you're on a phone call, and the upper one when you are on speakerphone or recording a video. Which one is giving you problems?
Have you tried cleaning the microphone port? Some isopropyl alcohol and a soft brush often helps if the hole is gummed up.
由 Jerry Wheeler 完成的