Loud background noise during call.

[BlackAudiA5]

Whenever I have a phone conversation with my wife who also has a Galaxy S9 plus it sounds like she's banging pots and pans in the background. She swears she's sitting in a quiet room all by herself. Anyone have a clue how to troubleshoot this or suppress the background noise? TIA

 

[B. Diddy]

Is she using a wired or Bluetooth headset? If so, could it be that she's inadvertently rubbing or bumping the microphone of the headset?