Dolby Sequel Boosts Modern Sound

Pro Logic II Turns Television Into Soundtrack

16-Aug-01

In this hazy season of the summer blockbuster sequel, Dolby Pro Logic II has slipped quietly into a limited number of home theaters.A sequel to Dolby Pro Logic, that long-ago surround-sound format succeeded by the now-familiar Dolby Digital? The same Dolby Pro Logic, an analog child of the '80s, seemingly consigned to the irrelevance of a historical footnote, like the eight-track tape? Yes, that Dolby Pro Logic is back, still analog but modernized as a sort of administrative assistant to Dolby Digital. Yet Pro Logic II goes where Dolby Digital can't -- it transforms a two-channel CD and even FM radio into convincing surround sound. It also turns television shows and older videos encoded in basic Dolby Surround into a multichannel soundtrack that sounds more like Dolby Digital.Pro Logic II emerges as a transition technology, though potentially as vital -- at least in the short term -- as Dolby Digital. The future might be multichannel, but the present is stocked with two-channel music collections. There's a huge, built-in market awaiting Pro Logic II.Unlike other new technologies before it, Pro Logic II is available immediately in the lowest-priced components. Onkyo's TX-DS494 receiver, which lists for $329 and is frequently available for less than $300, features Pro Logic II with the customary Dolby Digital and DTS formats. Even on this entry-level model, Pro Logic II's performance is exceptional.To save the cost of a scorecard, here's a rundown of the Dolby roster: Dolby Surround produces three channels, two in front and a monophonic surround; Dolby Pro Logic adds a center-channel signal; Pro Logic II adds a synthesized stereo signal in the rear; Dolby Digital and DTS feature actual full-range stereo in the surround channels and a low-frequency-effects channel for a subwoofer. Both Dolby Surround and the two Pro Logics are matrixed formats that extract information from a two-channel analog source. Dolby Digital and its rival, DTS, have six discrete channels of full-range digital audio.Technologically, Pro Logic II is no Dolby Digital. But Pro Logic II improves substantially on the DSP, or Digital Signal Processing, modes available on today's receivers -- the reverb-heavy ``hall'' or ``rock'' or ``jazz club'' or ``stadium'' settings that alter music or a TV's audio signal beyond recognition. For background music, I've always preferred a simple ``five-channel stereo'' mode. Pro Logic II is like five-channel stereo trying hard to be pure Dolby Digital -- front-channel vocals probably will appear in the rear channels, but reformulated just enough to make it sound like true surround. Although Dolby says no reverb is added to Pro Logic II, some echo effects can be detected. It doesn't hurt much. The more you get used to Pro Logic II, the more you like it. There are separate settings for movies, which place greater emphasis on the dialogue-heavy center channel, and for music, which enhances the surround effects.Pro Logic II was developed by Jim Fosgate, founder of Rockford Corp., whose products range from Rockford Fosgate mobile audio components and Hafler loudspeakers to Fosgate Audionics surround-sound processors. Fosgate, who holds 25 audio patents, has worked with multichannel sound since the days of quadraphonics. Dolby bought the rights to the technology, which should become a standard feature in every new receiver by the end of the year.It's so good that it's worth waiting for. Kenwood, Denon and Sherwood are also among the first manufacturers to offer Pro Logic II receivers. The Onkyo TX-DS494 would be the perfect low-cost entry into small-room home theater if not for its lack of speaker-parameter settings. These fix the amount of delay between the time a sound emerges from speakers in the front and rear, which creates the ``surround'' sensation to fit the size of your room. This is a basic feature built into every other audio-video receiver I've seen. Despite this incredible omission, the TX-DS494 does everything else so well that it's hard to overlook.Just like Pro Logic II. Dolby has a blockbuster in the making.The music industry's future is looking a lot like the movie industry's present. A recent report by Booz-Allen & Hamilton, a management consulting firm, predicts the music industry will use a similar progressive-release strategy.The movie industry begins with a theatrical release, then works down to home video, pay-per-view, pay TV and finally network TV and syndication. The music industry could open with radio/music television/touring, then a CD release (average price: $13.81), followed two months later by digital download ($2-$3 per track or $14 per album), and six months later by online MP3-type digital subscription ($10 to $20 a month). Finally, three months later, would come deep-discount record-club sales ($5 to $19).