"What's possibly left to add to an A/V receiver?" industry observers and reviewers ask at the end of each new product cycle. But always, by the time the replacement model has been introduced, manufacturers have found plenty to tack on. Only owners of last year's "state-of-the-art" A/V receivers can say how worthwhile are these additions, refinements, and upgrades.

For those of you shopping for your first flagship receiver, Denon's new AVR-5803 is a very serious upgrade of the AVR-5800. Added are the latest of everything found on top-of-the-line models from a few other manufacturers, plus something unique: a proprietary multichannel, high-resolution, Ethernet-like digital interface Denon calls Denon Link, meant to be used with Denon's DVD-9000 DVD-Video/Audio player.

Retained from the AVR-5800 are a host of pluses: seven channels of superb-sounding 170W amplification, every surround-sound scheme then known to man, THX processing and certification, almost unlimited input/output flexibility, and exceptional engineering and build quality. Also held over are a few negatives: Denon's pitch-black faceplate, impossible-to-read gold lettering for the knobs, buttons, and LEDs (keep a flashlight handy), the AKTIS RC-8000 LCD touchscreen remote (you'll love it or hate it), and a complicated, jargon-filled, sometimes incomprehensible instruction manual.

New with the AVR-5803 are THX Ultra2 certification and a number of THX-related performance and flexibility enhancements, Dolby Pro Logic II, DTS 96/24 decoding, five selectable subwoofer crossover points, video conversion from composite to S-video to component video (including onscreen display in component video), video switching bandwidth doubled from 50MHz to 100MHz, two sets of 7.1-channel analog input/passthroughs, and, of course, Denon Link.

New Innards
While the AVR-5803's exterior resembles the AVR-5800's, much of what's inside is new, including an arsenal of new DSP, D/A, and A/D processing chips. Two new 32-bit floating-point DSPs from Analog Devices, both SHARC Hammerheads, handle Dolby Digital, Dolby Pro Logic II (Music and Movie modes), Dolby Digital EX, DTS, DTS-ES Discrete and Matrix, DTS Neo:6, DTS 96/24, THX Ultra2 Cinema and Music, the usual DSP synthesized surround modes that most audiophiles hate, and Denon's 5- and 7-channel stereo modes. Whew!

There are new high-resolution 24/192 A/D converters for all analog inputs, which analog purists can bypass in Direct or Pure Direct (all video circuitry turned off) mode. However, there is no bass management when you bypass in this way. Bass management is available in other modes, passing the signal through the hi-rez A/D-to-D/A conversion process.

Also packed into the AVR-5803 are 16 Burr-Brown DACs, all PCM-1738Es capable of decoding DSD (SACD) bitstreams and operating in noise-canceling differential mode. At press time, Denon had still not been given the go-ahead to pass an SACD signal through its Denon Link connector. Once permission is granted, the AVR-5803 would be capable of decoding SACD signals via the Denon Link.

Another new sonic enhancement is Denon's Alpha 24 Processing Plus, found in the company's top-of-the-line CD players. A Denon-developed 16-to-24-bit algorithm extrapolates the "missing" bits before D/A conversion (stereo signals only). In addition, the AVR-5803's headphone jack includes Dolby Headphone processing, claimed to deliver a multichannel experience from stereo phones.

Describing all the features of this action-packed receiver in detail would fill an entire issue of the Guide. There's a flexible, very fine-sounding AM/FM tuner that's easier to access and use than the one in the AVR-5800. There are multi-zone facilities, an RS-232 port for future upgrades (and whatever else home-theater installers do with it to make you feel like the A/V king of your castle while confusing your wife and kids). If you like to play, configure, adjust, tweak, and customize, the AVR-5803 can become a lifelong toy. If you just want to push On and watch a movie, you can do that too.

Setup
The AVR-5803's front panel remains ergonomically challenged, but it doesn't matter—you'll inevitably use the radio-frequency (RF) controlled RC-8000 remote with its base-station receiver/battery charger. Whether because of my familiarity with the RC-8000 (it bred contempt last time) or because Denon has improved its ergonomics, I found it much easier—even pleasant—to use this time. The touchscreen buttons had a far more positive and predictable feel. Scrolling through pages to get to certain functions is still not my favorite thing to do, and if you're accidentally on the wrong page (for example, a multi-zone page when you should be on a main zone page), pushing a button can wreak havoc until you figure out what's going on. The RC-8000 is USB-equipped; PC owners can customize its touchscreen controls, but Mac users are out of luck. As is true with any remote, it's important that you get one in your own hands and try it before buying.

Despite its complexity and flexibility, connecting and configuring the AVR-5803 was relatively straightforward for this A/V receiver veteran, with one exception. Denon provides two sets of 7.1-channel analog inputs so you can, for example, have both an SACD multichannel player and a DVD-Audio player connected simultaneously, as I did. Even though I used the Denon Link cable between the DVD-9000 and the receiver, it would not pass copy-protected 24/96 DVD-A bitstreams, such as those found on Warner Bros. DVD-As. When Denon Link fails to pass a digital signal, the receiver can be set up to automatically switch to one of the 7.1-channel analog inputs. Let's just say pages 33 and 34 of the AVR-5803's manual are the instructions from hell, partly because of the receiver's complexity, partly because of the bad translation, and partly because of the writer's insistence on using jargon, acronyms, and initialisms instead of complete sentences.

With three sets of component-video inputs, five coaxial and six optical digital inputs (all assignable), Denon Link and AC3-RF, multiple A/V and audio inputs, and two 7.1-channel analog passthrough inputs, you're unlikely to run short of ins and outs no matter what your home-theater system requires. While the rear panel's many connections will initially intimidate the inexperienced user, its ultra-clean layout should make hookup pretty straightforward.

Like the AVR-5800, the 5803 lets you configure your system to include cinema surround speakers on the sides, music surround speakers in back, and rear-surround speakers for the sixth and seventh channels in DTS-ES, Dolby Digital EX, and THX Surround EX applications. For those unfamiliar with them, the rear-surround speakers fill in the rear soundfield, much as the front center speaker fills in the front soundfield. So far, however, only a limited number of films have been so encoded. [Using DTS-ES or Dolby Digital EX processing with 5.1-channel soundtracks not encoded for them will result in technically inaccurate playback. It might be subjectively pleasing, but this depends on how the surround channels were mixed. In some cases, the surround information might largely collapse into the single rear speaker of a 6.1 setup.—TJN]

Configuring my system via the AVR-5803's onscreen display was reasonably straightforward. Still, as with other complex, feature-laden receivers outfitted with less than adequate instruction manuals (i.e., most of them), those who buy an AVR-5803 as their first A/V receiver will likely suffer toxic shock during setup and use. But once past that stage, they'll be in for a real treat, sonically and feature-wise.