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Q I have a Denon AVR-4310CI A/V receiver. Although I have speakers connected for all seven main channels, I have never heard a movie with 7.1-channel sound. My sources are Blu-ray and Verizon Fios HD. What do you think is going on? —Mister Phillip

A As far as I know, movies shown on FIOS HD don’t have 7.1 sound, though there are plenty Blu-rays with 7.1-channel soundtracks—some of which you’ve probably already watched. This leads me to believe that the issue lies with the Denon receiver’s setup.

Looking at the AVR-4310CI’s manual, it says you need to select the Amp Assign: Normal option during setup for it to output Surround Back channel audio (the two “extra” channels you’ll hear when watching a 7.1 movie). It also says that the receiver’s Amp Assign option is set by default to “Zone 2,” which means that no audio will be routed to the Surround Back channels unless you've switched that option to Normal during setup. All this info, of course, is buried deep in the Denon’s manual, so you can be forgiven if you’ve overlooked it.

Once you’ve got everything set up correctly, there are a few options to explore on the AVR-4310CI that will make the most of your 7.1 speaker setup. When watching non-7.1 movies, you can activate Dolby Pro Logic IIx, a processing mode that derives 7.1-channel surround from stereo or 5.1-channel soundtracks. Another option that does something similar is the THX Ultra2 Cinema mode, which uses a technology THX calls ASA (Adaptable Surround Array) to expand the two surround channels in 5.1 soundtracks to four. No reason to keep those surround back speakers in your system idle, right?