Since the earliest days of stereo—the first experiments with more than single-channel sound happened back in the 1930s—recording and playback have been based on a horizontal model: left-center-right, left-rear, right-rear. "Laterality," as it's sometimes called, can be exploited very well in creating plausible sensations of spatial events, especially by film-industry sound engineers. The believable reproduction of music is considerably more problematic.

In the real world, sounds come at us from all directions—not merely from front, sides, and back, but from above and below as well. Psychoacoustics experts, forward-thinking engineers, and even some audiophiles have long recognized the absence of vertical information as one of the biggest obstacles to truly realistic sound reproduction.

Enter Tomlinson Holman. The legendary engineer—he's the "TH" in Lucasfilm's THX—is again pushing audio's perceptual envelope with what he calls a "10.2-channel" system. With twice as many channels as Dolby Digital's 5.1, incuding two channels of ultra-low bass, Holman's system encodes, decodes, and accurately correlates vertical as well as horizontal sound cues. Those who've heard his system have raved about its realism. Stereophile's Tom Norton, who heard a preliminary demo of the system at January's CES, said "It was the most amazing multichannel sound I have ever heard. I was simply in the space occupied by the performers, with no sensation at all of the locations of the speakers or the size of the listening room . . . there were live music recordings that sounded . . . live."

In early July, Holman's new company, Los Angeles-based TMH Corporation, conducted its first public demonstration of 10.2 at an electronics store in San Antonio, Texas. Approximately 100 people heard the demo at Bjorn's Audio Video, an event deemed noteworthy enough to warrant a mention in the Wall Street Journal. This summer, TMH will conduct more demonstrations at locations throughout the country in hopes of generating interest among consumers and manufacturers. This fascinating development promises to explore one of the last great frontiers in audio, and will be followed closely by Stereophile.