The home theater receiver market has been the most rapidly adapting product category in the AV industry over the past few years. While many higher-end AV companies scramble to release one AV preamp that can decode the new codecs of Blu-ray, most receiver makers are already on second- or even third-generation units capable of all this and more. The Onkyo TX-NR906 is one such unit. Situated at the top of Onkyo's line and retailing for $2,299, it is designed for the high-end home theater fanatic and includes all the bells and whistles one would expect in a top of the line receiver.

Onkyo spared no features or functions in this piece, nor did they skimp anywhere else for that matter. Seven 145-watt amplifiers are inside, as well as state of the art HQV Reon-VX video processing with scaling to 1080p. The TX-NR906 is THX Ultra2 Plus-certified and allows for source-specific ISF video calibration to maximize the performance of each and every video source. Four-to-two HDMI 1.3a switching allows switching between two displays for systems that might utilize a projector for night viewing and a flat panel for days, or for displays in two different locations, though you cannot use it for a second zone. Three component video inputs, six composite inputs and six S-Video inputs and one output of each ensure all your legacy pieces will be supported. The Onkyo has network connectivity, is Microsoft Plays For Sure-certified for Windows Vista and has a USB port for connecting to various mass storage devices for music server use.

Every new audio codec is covered by the TX-NR906, including Dolby TrueHD, DTS HR Audio, DTS HD Master Audio, Dolby Digital Plus and all the legacy audio codecs. It also has Audyssey MultiEQ XT auto set-up, room correction software and Audyssey Dynamic Volume to control the often large differences in volume between shows and commercials, or to limit extremes of dynamics for night time viewing. Audyssey Dynamic EQ is also included, which insures that any level changes induced by Dynamic Volume are acoustically correct.

A 7.1 multi-channel input and preamp outputs are included, as well as dual stereo outputs for zones two and three, allowing the TX-NR906 to control up to three zones. Six digital inputs, three optical, three coaxial and even a phono input for moving magnet cartridges are present, allowing up to 11 stereo analog inputs. Control is covered with an RS-232 port, as well as Onkyo RI control jack and 12-volt trigger. AM and FM antenna ports and both XM and Sirius radio ports are there, too. An Ethernet port and a removable IEC power cord with a single ungrounded switched outlet finish off the connectivity.

The amplifier section of the TX-NR906 is not only powerful, but also extremely flexible. You can run any combination of the seven channels of power, utilizing all seven in a 7.1 system, or bi-amping the fronts in a 5.1 system. You can even bridge the front and surround channels to add extra power and control for two-channel listening. The receiver will even allow you to have two different front speakers, so you can use one set for movies and one for critical two-channel listening, or use two channels to power a second zone.

All these features come packed in a simple but effective case. A large green center display has characters big enough to be read at a distance. The included remote is highly effective, with all keys backlit and important ones being brighter, making them easier to identify. The unit measures just over 17 inches wide by seven-and-five-eighths inches tall by just over 18 inches deep and weighs 54 pounds. Onkyo includes everything you will need with the receiver, including the backlit remote, batteries, power cord, both AM and FM antennas, the Audyssey microphone and a sheet of nice stick-on speaker wire labels.

The Hookup
I received a show sample from Onkyo for this review. It came in a large black plastic flight case, so I simply wheeled it into my bedroom, unlatched the case and swapped it out for my current receiver. I ran my Sony BDP-S350 and Scientific Atlanta 8300HD DVR via HDMI cables, my Denon DVD-5910Ci with three pairs of interconnects to the multi-channel input and hooked my Marantz TT15 through a Dynavector P75 MkII phono preamp to a stereo input. The Onkyo has a phono input, but it is designed for higher-output moving magnet cartridges and I am currently using a low-output moving coil unit, so I required a separate phono preamp. I bridged the front speakers for two-channel listening, connected the speaker wires for my KEF 5005.2 system and was up and running in about 20 minutes. I took advantage of the included wire labels, so all my wires were even easier to identify.

I fired up the rig and went through the menus, assigned my sources to my chosen inputs and set up the video side. I next set all of the sources for exactly how I wanted each one to run. The listening modes, as well as video scaling and ISF calibration, can all be set independently for each source. The inputs are menu-assignable, allowing any source to use any input, and all sources can all be renamed to add that custom touch to your home theater.

My turntable ran in pure direct mode, bypassing all processing and video circuitry, while the Denon 5910 used the multi-channel analog input and allowed video. The menus were clean and beautiful to work through. They were simple, yet elegantly done and easy to navigate, taking only a few minutes to set up everything as I wished it to be. I ran the Audyssey auto room set-up and calibration, which took another 15 minutes, and I was ready to rock.

Performance
Hancock (Sony Pictures Home Entertainment) on Blu-ray was one of the first films I watched with the Onkyo. From start to finish, I was impressed. The Dolby TrueHD soundtrack gave me a sound field that was very large and tall, with solidity to the bottom end. The bass was fast, deep and seemed bigger and more involving than usual. This added depth on the bottom end made all the crashes and impacts more fulfilling, while the massive soundstage and exceptional balance of the rest of the system gave me pinpoint positioning of the more subtle effects of the film. Video was actually downscaled to match my plasma and was superior to the internal scaling done by my display itself.

I cued up an old classic with the Blu-ray of U-571 (Universal Studios Home Video) and again found the surround effects of the DTS-HD Master Audio track to be spot-on. The powerful bass of this receiver made the creaks of the submarine very lifelike, while keeping a depth and warmth to the vocals that made them truly lifelike. Small nuances were clearly portrayed, while the massive impacts could cause you to jump out of bed. The pings of the sonar had an eeriness to them that further enhanced the film.

I cued up some vinyl with Traffic's John Barleycorn Must Die (Island) in stereo 2.1 mode. I had the front speakers bridged, so they now enjoyed twice the power offered in any multi-channel mode. From the start of "Glad," I immediately noticed the exceptional depth of the bass in the opening notes of the piano, while the delicacy of the higher notes was clearly portrayed. The soft breath of the horns opening "Freedom Rider" had all the brassy edge I would expect, while coming across with warmth as well. The vocals on "Stranger to Himself" were wonderful, while the individual guitar notes jumped out of the speakers.

For some multi-channel audio, I cued up Alice Cooper's Billion Dollar Babies (Warner Brothers Records) on DVD-Audio and was treated to a wonderful session. From the huge dynamics of "Elected" to the eerie surround effect of the title track, I was hooked. The extreme listening level this receiver is capable of only enhanced the power of "No More Mr. Nice Guy." I employed near-painful volume levels without significant distortion, making it all the more enjoyable.

To further test the video scaling, I moved the receiver into my main room and connected it to my Sony 70-inch XBR display to test the 1080p video scaling. The Onkyo did a great job of scaling 480i cable sources and offered excellent edge detail and improved clarity. While not as good as native 1080p, it was markedly better than the processing in the TV itself by a large margin. The scaling did a great job with everything I put through it, including my PS3 for gaming.

Low Points
The HDMI switching has a slight lag displaying video when switching sources, or even channels for that matter, so people who constantly switch channels might find this problematic. For those of us who are more inclined to find something to watch and stick with it, the brief time it takes to lock onto a source will not be an issue. Mac users will have to use their iPods or some other form of mass storage device to use the music server function. It doesn't have wireless connectivity for this feature, either, so you may require an Ethernet cable to run your home theater.

Some will find the appearance of the Onkyo and its included remote to be somewhat simple, and they are, but everything is well laid-out and easy to use, making it more functional than many of the more aesthetically-designed units. It seems Onkyo directed all their attention to performance on this piece and it really shows.

Conclusion
The Onkyo TX-NR906 is truly a reference-level receiver, and while some will find its $2,299 price high, I assure you that you are getting what you pay for and more with this unit. It sounds fantastic, and that alone would make it worth its retail price, but the addition of its extensive feature set, dual HDMI outputs, the ability to decode every digital codec know to date, the full complement of Audyssey functions and the internal ability to independently ISF calibrate each video source to maximize performance are more than icing on the cake. They make this unit a true giant killer, one anyone looking to build a serious home theater needs to consider.

The set-up flexibility of this unit and the ease of using its seven amplifier channels are wonderful and make it equally at home in a dedicated high-end home theater or a combined AV and two-channel system. Whatever you are looking for in a top-end home theater receiver, the Onkyo TX-NR906 provides, from the state of the art video processing and scaling to powerful rich amplification and tons of flexibility, this piece offers it all and at a fraction of the price of some other receivers. The Onkyo puts out excellent dynamics for a receiver. While not as open as my $100,000-plus reference system, it gave me a large percentage of the performance and was quite enjoyable to hear. Many receivers costing much more than the Onkyo offer only a small increase in features, such as wireless streaming of audio. For my money, this is one of the best receivers currently made, regardless of price. When you factor cost into the equation, the Onkyo TX-NR906 is truly a world-class receiver and one I find myself constantly recommending to others.