Digital Wireless Stereo Earphones
/ EAH-AZ80, EAH-AZ60M2, EAH-AZ40M2, EAH-AZ60, EAH-AZ40, EAH-AZ70W

Phone calls

The voice of the person on the other end of the call is small.

Also raise the volume on the BluetoothR device, not just on the earphones.