Focus Unveils Wireless 7.1 Audio

For Home-Theater Speaker Systems

By Joseph Palenchar -- TWICE, December 9, 2008

Campbell, Calif. — Fabless semiconductor developer Focus Enhancements will go to next month’s International CES to demo a multichannel wireless-audio technology said to overcome the sound quality, interference, latency and cost challenges associated with other wireless technologies designed for multichannel home theaters.

The company’s Summit technology promises 7.1-channel sound quality that’s “virtually indistinguishable” from wired quality, and it’s affordable enough for use in mid-price homes theater in a box (HTiB) systems, said chief technical officer Michael Hudson.

Summit achieves its quality goals by, among other things, transmitting uncompressed 48kHz/24-bit PCM over the air, using forward error correction to overcome latency problems, and using the uncongested 5.1-5.8GHz U-NII band. That spectrum, which features 23 non-overlapping channels, was recently approved by the International Telecommunications Union (ITU) for worldwide unlicensed use near the IEEE 802.11a/n wireless-network band.

Other technologies that avoid interference include spread-spectrum OFDM (orthogonal frequency-division multiplexing) modulation, four-antenna diversity tuning in the speakers, dynamic frequency selection to hop to a channel without interference, and up to 10ms of audio interpolation to fill in lost packets.

The cost of embedding these technologies with good-quality amplification into all of the speakers of a $599-suggested HTiB would match the cost of building a wired HTiB with the same performance, Hudson claimed. At prices starting at $799, a Summit-equipped HTiB would actually be less costly to build than a wired HTiB with similar performance, he added.

 Hudson cited multiple reasons for the cost advantage. One is the elimination of passive crossover parts because Summit’s in-speaker chip incorporates digital active crossover. Another reason would be that power supplies embedded in each speaker would be smaller than the power supplies located centrally in an HTiB system’s main chassis.

The Summit chip also offers additional performance advantages unavailable even in $2,000 A/V receivers, Hudson claimed. Although AVRs and HTiBs offer speaker-level, speaker-delay and phase controls to maximize a sound system’s sweet spot, the sweet spot is limited to an area around the center of a room, he explained. But Summit’s implementation of these technologies is so flexible that the sweet spot can be focused into one corner of a room where a sectional couch might be placed, he contended.

To make it easy to set up a wireless system, Summit-equipped systems automatically discover speakers in the room and assign channels to them.

Sound quality exceeds that of wireless surround speakers currently supplied by HTiB suppliers, Hudson said, because those speakers use the crowded 2.4GHz band and a 12-bit wireless pipe, which delivers “less than FM quality.” Interference from other 2.4GHz wireless products in a store prevents retailers from demonstrating these speakers effectively, he added.

Summit’s range is limited in the first-generation chip to transmit audio within a 30-foot by 30-foot room, but the technology is scalable in future generations to extend the range to enable multiroom-audio distribution with up to 16 48kHz/24-bit PCM channels, Hudson noted.

Future versions of the technology could also deliver eight channels of 96kHz/24-bit PCM audio, but Hudson claimed the it’s difficult for the human ear to discern the difference.

First-generation summit chips are available as engineering samples, and production chips will be available in the first quarter.