Strange soft phone call, normal voice memo & zero video audio

If i’m not mistaken the back camera uses the microphone from the power flex cable for sound and the front camera uses the front camera flex microphone for it’s audio intake. Voicememos/Siri/calls with loudspeaker uses the bottom right microphone and normal calls pick up the sound from the bottom left microphone. Start of by testing with a new part then record again and see if it makes a difference.

Otherwise i would assume it’s related to audio IC on the motherboard, i dont think audio ic problems are very common on the iPhone 6S though.