KSC Develops Interference-Free Wireless-Speaker Technology

By Joseph Palenchar -- TWICE, 8/23/2004

San Diego — Contract manufacturer KSC Industries has developed a 2.4GHz wireless-speaker system that it contends is far more resistant to 2.4GHz interference than competing technologies currently available to consumers.

The solution, called Soundcast, is “immune to 2.4GHz interference of all types,” except in extremely limited circumstances, said senior applications engineer Jim Wei. It’s intended for use in active surround speakers and active outdoor speakers.

Soundcast uses diversity antennas, direct-sequence digital-spread-spectrum technology, memory buffers and bidirectional communication, which provides error correction and retransmission in case of data loss caused by interference from microwave ovens, 2.4GHz cordless phones and 2.4GHz wireless LANs. The data rate is 3.2Mbps.

The “ultra-low-latency” solution delivers 20Hz to 20kHz audio at +/-1dB with less than 0.3 percent THD, 85dB dynamic range, and greater than 95dB A-weighted signal-to-noise ratio up to 60 feet through four sheetrock walls while a 2.4GHz Wi-Fi network, a cordless phone and a microwave oven are in use.

KSC said its solution is impervious to interference from frequency-hopping spread-spectrum phones whose transmissions hop throughout the 2.4GHz band and completely mute the surround speakers in current HTiB systems that feature wireless surround speakers.

In 2.4GHz wireless LANs, KSC’s solution would experience light to medium amounts of muting only if the LAN is operating on channels five through nine and a wireless-LAN device is within 2 meters of a Soundcast component. In those cases, users could switch their network to channels one through four, 10 or 11 to eliminate muting.

The company isn’t promoting its solution for homewide distributed-audio applications because it can’t guarantee “100 percent quality of service,” given the size of homes and potential RF-blocking building materials, VP/general manager Malcolm Hollombe said. Nonetheless, said senior applications engineer Jim Wei, “95 percent of applications will be OK.”

The technology is no more expensive than current solutions incorporated in HTiB systems retailing for as little as $500, said Hollombe. KSC is offering complete modules and chipsets to suppliers on an OEM basis but will also design finished products, including HTiB systems, he said.

For HTiBs, the solution could be used to incorporate wireless transceiver and amplification in a powered subwoofer placed in the back of the viewing area. The enclosure’s amplifiers would power the internal subwoofer driver and two surround speakers that would connect to the subwoofer enclosure via speaker cable. Subwoofer and surround-speaker audio would be sent wirelessly to the subwoofer enclosure from a transceiver built into the HTiB’s main chassis or in the HTiB’s center-channel speaker. Alternately, suppliers could offer a retrofit transceiver/amplifier package for use with any HTiB system.

For outdoor use, KSC could design powered outdoor speakers that could be plugged into outdoor electrical outlets.

Modules and chipsets are in production.

KSC was founded in 1973 as a contract manufacturer specializing in audio. It designs and, through partner factories in China, manufactures audio products for the consumer, commercial, professional, studio, architectural, automotive and marine markets. Products include in-wall and in-ceiling speakers, enclosed home speakers, HTiBs, car audio speakers and digital and analog amplifiers.