Hope for Wireless?

Anyone who has experimented with wireless local area networks for audio—feeding rear/side speakers in a multichannel system, for example—can attest that the technology is far from ready for prime time. Prone to noise, interference, and dropouts, wireless audio systems require a tremendous amount of refinement before they'll meet audiophile standards.

The domestic intrusion caused by the necessary cabling in hardwired systems prevents many potential converts from joining the multichannel camp. A reliable, good-sounding wireless surround system could be the audio industry's next great leap forward. Several semiconductor companies are working on possible next-step technologies, among them Korea's Open Solution, Inc. The company has been shipping samples of its DWM3100 digital audio processor to manufacturers, hyping its low-noise, high-fidelity capabilities. A combination audio/data transceiver, the DWM3100 is claimed by Open Solution to deliver "nearly lossless CD-like" audio using a 4:1 compression/decompression scheme, retransmission error correction, and triple-redundant control code, with transmission at 2.4GHz, according to Mark LaPedus in an October 8 report on the EE Times website.

Some pundits might respond to that bit of news by stating that "good-sounding wireless" has existed for decades, in the form of FM radio. Indeed, under ideal conditions, FM is a truly high-fidelity format, one whose sonic potential has been all too frequently degraded by the heavy-handed application of peak limiting and dynamic compression by broadcasters eager to win the loudest-station-on-the-dial competition.

Even so, experimenters continue to tinker with ways to get more from FM. At the National Association of Broadcasters (NAB) Radio Show held October 6–8 in San Diego, Fraunhofer Labs, chipmaker Agere Systems, and partners Telos Systems and Omnia Audio demonstrated a system for broadcasting and receiving discrete 5.1-channel surround sound using the data channel of iBiquity Digital Corporation's HD Radio service. Telos marketing executive Clark Novak claimed the system offers "true, dramatic discrete playback," unlike competing systems that he described as "inadequate matrixed systems."

The NAB demonstration was announced as "delivering impressive, full surround audio without compromising the stereo signal in any way." The Fraunhofer/HD Radio technique was said to yield equally pleasing results to "users equipped with conventional stereo receivers and those owning surround receivers." As with many "derived from stereo" surround technologies built into multichannel receivers and preamps, the Fraunhofer multichannel uses all the information contained in the front two channels in addition to "spatial cues" transmitted in an ancillary data channel. The data rate is 80 kilobits per second (kb/s) for the stereo channels and 16 kb/s for the surrounds.

"The system is based on work by Fraunhofer IIS and Agere Systems in the area of 'binaural cue coding," stated a press release. "Three essential factors are required for the perception of a spatial audio image: level difference, time difference, and coherence between channels. These values are represented as a function of frequency and time with very compact coding, and allow for a huge data saving compared to transmitting all audio channels individually."

Using the technique demonstrated at NAB, a broadcaster with an "old-fashioned FM stereo license" could have a "state-of-the-art digital surround license for no additional cost," said Telos CEO Steve Church. Fraunhofer IIS is the originator of the MP3 and MPEG-4 HE-AAC codecs. Telos makes audio interface products; its subsidiary Omnia works in digital audio signal processing for TV, FM, AM, HD Radio, digital audio broadcasting, Internet audio and other applications.

Further technical developments in FM may be too late to revive its importance as an information and entertainment medium, however. Investor interest in traditional radio is at an all-time low, according to an October 8 report by Joe Flint and Sarah McBride in The Wall Street Journal, whose analysis appeared only a couple of days after an announcement by Sirius Satellite Radio that it had signed "shock jock" Howard Stern in a multimillion dollar deal to begin when his contract with Viacom, Inc.'s Infinity Broadcasting expires in 2006. XM Radio earlier landed Bob Edwards, the popular former host of National Public Radio's Morning Edition. NPR's firing of Edwards provoked protests by many NPR loyalists; when XM picked him up, the satellite provider got plenty of his listeners, too.

"The fundamental problem is that people just aren't tuning into radio the way they once did," the WSJ reporters noted. "As the industry consolidates and programming becomes less local and more homogenized, radio provides fewer choices and niches than competing media such as cable television and the Internet. Commuters are spending more time on their car phones or listening to compact discs than ever before . . ." In addition, motorists, the primary radio audience, are tuning into satellite services Sirius and XM Radio in ever-expanding numbers. One result is a dramatic drop in stock prices for big radio conglomerates—industry giant Clear Channel Communications, Inc. has seen its stock slip 33% this year. Investors have soured on the traditional radio industry because they don't see any growth potential, an inevitability built into the merger-and-acquisition mania that swept the industry in the wake of the Telecommunications Act of 1996. Satellite radio, by comparison, has nowhere to go but up.

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