The Onkyo TX-NR709 builds on the company's years of network support in home theatre receivers (it was one of the first), and includes excellent home theatre connectivity with fine audio and video support.
As a pricey receiver, this one supports the legacy connection standard S-Video, but it also has plenty of HDMI inputs. Eight, in fact, one on the front panel, along with two HDMI outputs. The unit fully supports the 3D frame-packed format and the Audio Return Channel when connected to modern TV sets.
The receiver has a USB socket on the front panel and Ethernet on the back. A wireless LAN adapter is available as an option, but we'd be reluctant to recommend it. It plugs into the receiver's sole USB socket, so while it might add networking in some situations, it also takes away the use of USB for other functions.
A brochure refers to this as a 7.2 receiver and, yes, there are two subwoofer outputs. But they both carry the same signal, so it's really 7.1.
Onkyo uses the Audyssey MultEQ XT system for its speaker calibration. You are given a choice of a quick set-up with one place of measurement with the supplied microphone, or a more detailed one in which the microphone is set to occupy three different positions in turn. Both work well, with the latter providing a subtle improvement in sound balance, thanks to it having a slightly better sense of the listening room.
At the end of the process you can choose whether to use Audyssey's "Dynamic EQ" and "Dynamic Volume". We'd suggest that you have both off. They fiddle with the tonal balance according to the volume level on the mistaken assumption that adjustments should be made to counter differences in human ear sensitivity at different levels.
The receiver is certified "THX Select2 Plus". THX certification does not guarantee that a receiver is better than any other, but it does guarantee that it is not a dud.
With 110 high fidelity watts available from each channel, and with the frequency performance of the connected loudspeakers tweaked to work best in our room by the receiver's calibration routine and EQ, it sounded excellent. Or, rather, it did after we switched off the silly "All Channel Stereo" default sound mode for all two channel sources.
The unit has excellent video processing, which you can use to convert lower resolution stuff (including from HDMI inputs) into high-resolution HDMI output. Note, this won't typically improve the picture, but it does about as good a job as can be done.