Some phones have two microphones. A primary microphone is aimed to your mouth to record your voice, whilst also picking up any noise from around you. In a single microphone circuit, this comprises all the data that is sent via the air waves to the receiving handset.
With a secondary microphone located elsewhere, usually near the top and on the back of the handset (so it doesn’t pick up so much speech), a lot of background noise can be removed.
You can try these steps, that may or may not reduce noise:
- Go to in-app Settings
- Select Recording
- Select Mic selection
- Choose Rear microphone or Raw audio
This allows for a different mic to be used for recording. Note that this does not work on all phones. The quality of recordings depend largely on the mic hardware itself.