The small round hole in the phone has a very important function
The sound waves are transmitted through this microphone and amplified, helping the listener on the other end of the line receive clearer sound. Without a secondary microphone, the call quality will be significantly reduced.
Most mobile phones today have two noise-canceling microphones, one on the top and one on the bottom. When the phone is affected by environmental noise, the secondary microphone will reduce this noise, leaving only the sound of the call. This technology is called “dual microphone noise reduction technology”, making the call clearer even in noisy environments.
