Troubleshooting for malfunction of amplification is described as below : 1. Press the Volume Up button to increase volume when you talk on device.   2. Play music to confirm that the receiver/speaker functions properly. 3. Restart your device.  4. Update firmware to the latest version：Settings > System > System update > Check Update.    5. Remove any objects that may be obstructing the receiver/speaker, such as a protective case. Then check whether the receiver/speaker is blocked or dirty. If necessary, use a soft brush to clean the speaker or earpiece. 6. Access to Safe Mode ( long press power key > Tap and hold " Power Off " > Tap " ok "：If your phone / Tablet works well in Safe Mode ,malfunction may be caused by some 3rd party apps . Please reboot your device and check again if it works well. 7. Backup your data and perform factory reset.    If the above steps don't resolve the issue, please contact ASUS Product Support for help.