Make sure your Internet connection is not being used by anything else (Netflix, uploading/downloading on the PC, etc.). With nothing else using your Internet connection, you should not be having audio problems. If your audio has problems with nothing else using your Internet connection, QoS will be of no help. If that's the case, try this:
1. Dial *** 0
2. Enter option 27 and press #
3. Press 1 to set a new value
4. Enter a value of 1 and press #
5. Press 1 to confirm/save
6. Hang up
7. Wait for the OBi to reboot