Suppliers Make Room For Fine Sound

New York— Audio suppliers are making walls, in a sense, disappear so they can deliver the best possible sound quality.

Yamaha, Bang & Olufsen and Meridian are the latest companies to add digital sound processing (DSP) to products to adjust system response for the effects of a room's acoustics, including the effects of speaker placement within a room.

In 2001, Pioneer added room-acoustics compensation to receivers for the first time, and in 2002, Bose upgraded two of its DVD-based Lifestyle home theater systems with room-compensation technology. Acoustic compensation in car interiors for wind and road noise is available from select automakers and aftermarket suppliers.

Joining them is Yamaha, which will launch its first three receivers with automatic acoustic compensation. They include the $799-suggested RX-V1400 and $999 RX-V2400, both available in September, and a flagship receiver to be unveiled at the CEDIA Expo. Yamaha's technology automatically analyzes room-acoustic and speaker-placement influences via an included microphone. The products then use digital parametric equalization to automatically compensate for response errors at seven points in the audible frequency range, said national training manager Phil Shea. The receivers will also be Yamaha's first to upconvert composite and S-video to component video.

For its part, Bang & Olufsen plans September shipments of the BeoLab5 active speakers through B&O-branded stores at $16,000/pair. They're the company's first speakers to incorporate DSP, which corrects for speaker-placement boundary effects and room acoustics in the 20Hz-300Hz range, time-aligns drivers, and performs crossover functions. It's powered by a digital Class D amplifier.

Acoustic compensation in the BeoLab5 is also automatic, in part because of a built-in motorized microphone that takes response readings from two different positions.

The Acoustic Lens design, which takes the shape of two saucer-shaped tiers, maintains tonal balance throughout the main listening area by narrowing the vertical dispersion of treble and midrange frequencies and widening horizontal dispersion to 180 degrees, said product manager David Zapfel.

Also at the very high end, Meridian has begun shipping new software and a DSP card for its 861 digital processor, available at $14,740 with the upgrades. The room-correction enhancement controls room modes at low frequencies, where the company said room problems are the most noticeable and for which extremely effective results can be obtained for a broad range of listening positions.

"Virtually automatically," the enhancement measures room response and then automatically builds a series of digital filters that reduce the reverberation time of significant room modes, the company said. Users set up a measurement microphone — such as a sound-level meter — in the listening position and plug its output into an analog input on the processor. The user then chooses the room correction option, and the system "builds the appropriate filters," Meridian said. Multiple sets of filters can be programmed into presets for different types of listening.