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

Finally, a future-proof, PC-friendly AVR that sounds great, too.

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.)