I'm surprised that the ARC system wouldn't detect the speakers hooked up and calibrate them accordingly. With my Yamaha, this is the case. You can't actually access the surround modes, except for DPL2 and the Yamaha ones, but all the true digital surround formats are detected and used depending on what is sent from your sources. Is this what you're having a issue with? Be sure your sources are set to output Bitstream (or is it PCM) over HDMI. Sorry, been so long since I set it and literally forgot it.