Chosen Solution

cannot hear when i record audio on memos or whatssap etc. just a crackling static sound.i record video sound working fine.tried all reset setting, power + home button , off noise canceling, still not working..its my Iphone 5s second

There are 3 microphones in the iPhone. https://support.apple.com/en-us/HT203792 The bottom microphone is for Voice Memo and phone calls. The other microphones serve as error cancellationThe (top) front microphone is used for FaceTime calls, Siri and selfie videos with the front camera (FCAM). The top back microphone serves as error cancellationThe (top) back microphone is used for videos with the rear camera (RCAM). The top front microphone serves as error cancellation  Make sure you update your device to the latest version of iOS and then try to isolate which microphone is not working properly by trying each individual microphone with the related apps above. Check the microphone port holes for dust and debris which could be attenuating the sound. If the issue affects more than one microphone, then it could be the Audio Codec IC on the logic board. Anything at the logic board level will require micro-soldering so you would need to find a repair shop that offers those services.