If available, HDMI audio output typically should be set to "bitstream" audio mode.
When set, your device will bypass its own internal audio decoders and send the Axiim Q your undecoded signal. Bitstream audio mode will typically be found on Blu-ray players and other devices capable of HD Audio such as DTS-MA or Dolby TrueHD.
Other devices such as set top boxes that do not support HD Audio will typically have a Surround Sound mode or Stereo Mode. Surround Sound mode should be selected.
For game consoles such as the Xbox One or PS4, uncompressed PCM will be preferred. For instance on the Xbox One you should set either 5.1 uncompressed or 7.1 uncompressed depending on the numbers of speakers you have paired to your Axiim Q.