B&K AVR 507 Series 2: Low Key and High Octane

Never underestimate the power of a first impression. With a killer instinct for trends, the A/V industry knows that it’s the buttons, lighted dials, and marquee-style displays that net more impulsive creditcard swipes than any red-eye-inducing spec list of power ratings and harmonic distortion numbers. Today’s A/V receivers are such exhibitionists that only the missing set of 22” chrome spinners keeps them from a guest spot on Pimp My Ride. What’s up, then, with the stately and dignified B&K AVR 507 Series 2? While its competitors bristle with a bazillion buttons, the B&K’s sophisticated software has reduced the clutter on its brushed-aluminum front panel to a pair of knobs, a few identical pushbuttons, and a spacious, highly-legible display. This seriously complex (and seriously heavy) seven-channel AVR is loaded to its heatsinks with the features and specs that truly matter.

The B&K AVR 507 sports 150Wpc, delivered up by a MOSFET output stage, Class A pre-driver input stage, and computer-grade electrolytic capacitors. At its DSP heart is a Motorola 371 processor with 24- bit/96kHz A/D and 24-bit/192kHz D/A converters. Future-proofing is a guiding philosophy at B&K. Thus the AVR 507 was built around a modular design that will allow for DSP, digital receiver, and D-A/A-D upgrades down the road. The complete menu of surround decoders includes Dolby Pro Logic IIx, complemented by the ever-useful Cinema EQ mode to remove excessive brightness from film soundtracks. But purists haven’t been ignored— DIRECT MODE offers a full stereo analog bypass. Video hasn’t been disregarded either with three 100MHz component inputs and video transcoding (see Setup Notes). In further support of system integrators, the B&K has more connections than a room full of Washington lobbyists—dual IR inputs, four 12V triggers, an RS232 data port with RJ-45 jack, and an IEEE1394 (FireWire) jack and internal driver. On the front panel a headphone jack is provided, but there are no A/V inputs for the impulsive gamer to hook into.

Bass-management capability is a cut above the norm, allowing the user to choose from a wide range of crossover frequencies and high- and low-pass slope settings—a feature that takes into consideration the size and potency of the satellite speakers. Subwoofer phase can also be inverted. The ULTRA setting provides an LF feed to the subwoofer, while enabling the rest of the system to run full-range.

Sonically, the AVR 507 was on a par with the majority of other fine solidstate amplifiers. Although a bit dry in the treble, it was never edgy or coarse. There was a hint of warmth in the mids and a satisfying sense of weight in the lower mids and upper bass. Transient speed was excellent, although harmonics were not quite as sweet and extended as those of my reference Plinius stereo integrated. The AVR 507 quickly established its 150Wpc credentials with tight-fisted control in the lowest bass octaves and dynamics that never seemed to run short of breath, even during musical slug-fests like Pictures At An Exhibition or the 1812 Overture [Minneapolis/Dorati, Mercury]. Whether the material originated from a stereo or multichannel source, the B&K was never at a loss in the control department.

The AVR 507 played big and had plenty of headroom—an attribute that served it well during Green Day’s “Wake Me Up When September Ends” [American Idiot, Reprise], when the intimate, guitar-backed vocal gives way to the entrance of a huge drum and the fully-ignited band. It also exhibited a fine hand reproducing inner details like the double-tracked, John Lennon-like vocals of Justin Barens of The Redwalls [De Nova, Capitol]. It handled speakers of medium and even low sensitivity (the Focus Audio FS78SE and the ATC SCM20-2) with relative ease. During the second movement of the Mahler Fifth Symphony [St. Petersberg/Temirkanov, Water Lily], it wasn’t quite as expansive and effortless with strings as I’ve grown accustomed to on this SACD recording. It didn’t show the same sensitivity with finely layered pianissimos as it did with rousing fortissimos. A trailing-edge hardness crept over the brass section; the wind section was a little airless and dry. Its soundstaging was excellent, however, particularly in the width of the proscenium, though the B&K couldn’t quite match that feat in the depth department because of its slightly forward perspective.

In multichannel mode, the “theater” of a live-broadcast sporting event can trump even a top-notch movie soundtrack. I recently watched U.S. Open Tennis in widescreen high-definition, and Dolby Digital carried over the UHD channel on DirecTV. But despite the vivid high-def images, it was the B&K’s immersive and uniform surroundsound performance that utterly transformed the experience. Twenty-thousand screaming fans in the cratersized stadium court energized the room with shifting waves of applause. The individual “oohs” and “aahs” during a well-played point made me feel like shouting support myself. Since microphones were placed at both ends of the court, the finer details also helped the drama play out—the constant chirp of tennis shoes, the occasional buffet of wind, a chair umpire’s call, the flat rebound of the ball as it was nervously bounced between points by the server. (Thankfully B&K offers easy remote access to fine 0.5dB trims of level, for tailoring individual channel output to the source material.)

The home-theater experience is lost without center-channel performance that is both naturalistic and articulate. And nothing is more revealing of the plusses and minuses of the center channel than a dialogue-heavy movie like that pulp-pleasure Sin City, which overlays reams of narration on the violence- heavy plot. What is significant is the timbre change between the distinct worlds of narrator and actor. Clive Owen would be one instance. As narrator his voice is heavily damped, devoid of ambience, and forward, more directed and apart from the screen. As soon as the movie shifts into the actual scene, the character’s dialogue drops back into the screen environment, where it rejoins the voices of the other actors, the sound effects, and the ambience.

The recently released extended version of Gladiator not only has some incisive and uproarious commentary tracks with Russell Crowe and director Ridley Scott, but a few well-acted, character-driven sequences that are worth a peek. One scene depicts a military execution where the emperor Commodus questions a lieutenant’s loyalty and his willingness to carry out orders. Underscored by somber strings, military drumming, and wind gusts, the archers stand with arrows drawn-back at the ready; the creak of the bows under tension can be heard during the close-up, followed by the whistle of air upon the arrows’ release, and the thud of impact as they pierce the chests of the accused. It’s a scene built on small details—none of which are missed by the AVR 507.

The B&K AVR 507 Series 2 is geared for high-performance enthusiasts who don’t get hoodwinked by buzz and gimmickry, who’ve matured beyond the basic “impulse buy,” who take their home theater seriously. It’s got the features, flexibility, and futureproofing that matter most in a market riven with change. Bottom line: First impressions are important, but it’s the lasting impressions that make the difference. Game, set, and match to B&K.

Setup Notes: A Perfectionist’s Paradise

Thanks to the clean OSD (on-screen display) and the redoubtable Home Theater Master MX-700 (fully trickedout and pre-loaded by the B&K pit crew), the set-up procedure is as comprehensive as it is easy to master. The front-panel pushbuttons have multiple functions that correlate with the appropriate menu items depicted in the display. The B&K software also goes a couple steps beyond the predictable speaker set-up conventions of size, distance, and level. There is a whole host of presets for each and every input, so that users can choose a default processing mode, a decoder, a speaker-channel configuration, and source levels. Furthermore, there are 40 available custom presets (I haven’t even mentioned macros!) that allow the user to take a virtual picture of preferential settings and save them for later recall. For example, if you want different trim-levels and EQ for a specific radio station, you can save them to a preset for that station. Very cool. The procedure however is a little tedious, (each radio station needs to be input one by one), but B&K has hinted at some shortcuts it’s considering.

Rather than deal with the unpredictable and often irreproducible nature of most auto-calibration procedures, B&K has created its own brace of equalization programs. The first is ROOM EQUALIZATION designed to improve timbre matching between speakers in user-selectable bass and treble ranges. This is especially useful to compensate for characteristically bright movie soundtracks or to smooth response when placing speakers behind a projection screen. Additional pre-programmed EQ settings like LOUDNESS (low-level listening), VOCAL (a nighttime mode, but also applicable for PCM or analog), and FLAT (no EQ) can be selected on-the-fly via the remote control.

Of even greater interest is the ROOM RESONANCE menu—a system of notch filters and shelving equalizers that can subdue in-room resonant peaks in the bass region that tend to muddy up lower-octave response and cloud the sonic picture further up in frequency band. With the aid of your own SPL meter, B&K’s tone generator sweeps the listening room in the 20Hz to 300Hz range. The user notes the three highest peaks in that range, as well as the frequencies above and below the peak where the difference in frequency is less than 3dB. Using B&K’s simple formula, you simply adjust the notch level and notch width (between 4.8Hz and 33.4Hz) accordingly. Tricky? Not at all—actually it’s fun, sonically rewarding, and much more involving then “going couch potato” during conventional auto-cal.

This is one very “PC” audio-video receiver. Mind you, you won’t need a laptop to blast off into home-theater heaven, but if keyboard optimization and integration are your thing by all means take advantage of the SR10.1 Remote Editor Software (included) and the BK-Suite set-up software (a download from the B&K Web site).

Even though the SR10.1 remote control comes pre-programmed with 10 input devices labeled to match the inputs on the back panel of the 507, the Remote Editor software makes it a drag ‘n’ drop delight to personalize the intelligence of the SR10.1 through controlling extra source devices, adding macros, and creating punchthroughs. The BK-Suite software can more completely and easily optimize all system setup and preset functions and favorites for Zone A and B, and save them together in a *.bkd file.