THX Today
 I recently had a chance to
meet with Laurie Fincham, THX's director of engineering. I suspect most people recognize
the THX name, primarily from watching movies in theaters. That's understandable because
the THX logo has been synonymous with high-quality movie-theater sound since 1983, when it
first began certifying theatrical sound systems with its Theater Alignment Program (TAP).
But in the last 20 years, this high-tech think tank, research, and measurement facility
has done so much more.
Fincham is a jazz bass player and an almost legendary
figure in audio circles. His first job fresh out of engineering school was at Celestion,
where he was asked to figure out why the famous Celestion "greenback" 12"
instrumental speakers -- the driver that gave rock legends, such as Jimmy Page, Jimi
Hendrix, and Eric Clapton, so much of their signature sound -- were blowing up right and
left. I mean, were proving problematic. Short version: They could take about 12W before
self-destructing, so Jim Marshall's early 50W amps were just about right for a 4 x 12
cabinet. When he came out with his 100W amp, anyone who wasn't using a stacked pair of 4 x
12s started making frequent trips to their nearest Marshall repair facility.
Later Fincham joined KEF, where he pioneered the use of
computer modeling to analyze the electro-acoustic behavior of the driver and crossover
combination, which meant that acoustical second-, third-, and fourth-order rolloffs
could be accurately (and quickly) optimized. Before Fincham’s work, designing a
crossover consisted of choosing a textbook crossover and then making changes in it until
it sounded "right." Fincham made it possible for designers simply to choose
their crossover and their target slope and have the computer crunch the relevant numbers.
If, as I have frequently observed, it is difficult to buy a bad-sounding loudspeaker these
days, then surely a lot of the credit must go to Fincham and his groundbreaking research
and techniques.
Fincham joined THX in 1999, but I'm getting ahead of
myself. First, some THX history:
THX's TAP certification standardized theater sound and
served as a guarantee that what audiences heard on playback was identical to what the
filmmakers heard in creating it. How much that means to you depends on how much you love
the big movie experience, of course, but I know a few folks who won't even see a film if
they can't see it in a THX theater -- they'll wait 'til it comes out on DVD and watch it
at home, thank you very much.
As home theater became increasingly popular in the '80s,
Lucasfilm (THX's parent company) realized that there were no real standards for
home-theater-sound reproduction -- a situation that led to the same hodgepodge of quality
levels that had originally prompted it to seek rigorous standards for movie theaters. In
1980, after a four-year research project, THX unveiled its Home THX Program. Home THX was
a product-certification program intended to present a uniform standard, establishing the
minimum performance level for Dolby Digital, Dolby Pro Logic, and other surround formats.
The point of Home THX's licensing requirements was the same as its TAP program: to ensure
that the home-theater audience heard what the filmmakers intended.
The Home THX program standard followed from the same
principles THX had developed for movie theaters: it placed a premium on loud, undistorted
sound (including peak levels) and a diffuse, non-directional sound from the rear channels.
THX speakers had to reproduce clean sound at very high levels, and the satellite-subwoofer
system with its unvarying 80Hz crossover was specified. At first, the THX spec also
required controlled-dispersion front speakers, and rear speakers that used multiple
drivers to "decorrelate" the sound. THX-certified surround-processing devices
had extra settings, beyond Dolby's own minimum requirements, designed to make the surround
stage "bigger" and to introduce high-frequency equalization. This was based on
the premise that movie sound is mixed for speakers that project through the screen and is
mixed "hot" so that the screen doesn't muffle the sound.
The program proved controversial. Some consumers were
confused by the concept of a licensed certification program and wondered if certification
was "purchased." It was not, but manufacturers did have to pay a licensing fee
to advertise themselves as "THX certified." Others objected that the speaker
standards were based on regularly shaped large spaces, such as those employed by movie
theaters, and didn't work well in odd-shaped living spaces.
THX's original Home certification program became known as
THX Ultra when the company introduced a less-rigorous standard intended for smaller rooms
than its original spec. They named the new compact-theater standard THX Select.
In 1999, THX had two major developments: Laurie Fincham
brought his quarter-century of loudspeaker measurement expertise to the company, and THX
and Dolby Laboratories co-developed Surround EX.
THX EX (also called Dolby Digital EX) added a speaker, or
two closely spaced speakers, behind the listener. In 5.1 surround, the
"rear" channels actually belong on the side walls; in THX EX or Dolby Digital EX
systems, the "extra" speaker(s) should be placed in the middle of the rear wall.
Last winter, the company announced the latest version of
Ultra, called Ultra2, which relaxed certain standards (speaker directivity), tightened
others (subwoofer performance), and added new features (EX recognition, high-bandwidth
video switching, and multichannel-music compatibility).
In May, THX spun off from Lucasfilm Ltd. to become
functionally independent. While Lucasfilm retains ownership, THX is now looking for new
areas to apply its research and testing expertise. It recently developed and specified the
performance parameters for the 2003 Lincoln LS. The company has partnered with Velodyne
Acoustics Inc., developing two subwoofers that meet its Ultra2 Certification -- the HGS-18
and HGS-15 powered subwoofers.
The firm also collaborated with Dell Computers to create a
THX-certification standard for PCs. "We realized that … people wanted to play
DVDs or CDs on the computer," said Fincham. "The overall system performance,
though, was a function not just of the speakers, but of the computer configuration as a
whole."
That led the THX team to develop a software program that
walks the consumer through set-up, and tweaking the computer to reproduce music and video
better. The team also created a graphics card that compensates for the blue tinge DVD
acquires when viewed on a computer monitor.
So where does that leave THX? They are working with
Lucasfilm to develop digital cinema, which is still in its early days yet, but might
transform the logistics of the movie industry and banish forever the days of watching
scratched or fogged prints.
And Fincham is enthusiastic about helping manufacturers
create new home-theater products that actually accommodate life as we know it. As he
looked around a gray-flannel-clad table where a gaggle of New York's freelance audio
writers were hunkered down, Fincham asked, "Does anyone actually listen to
movies at Dolby reference level?"
Heck no, we all responded.
"Precisely," Fincham nodded. "At 105dB, it's
just too loud. You could use it to calibrate your system and then change the volume
as needed, but it's a classic example of a situation where the user has to acquiesce to
the system. But chips are cheap -- all the necessary EQ adjustments should take place
automatically as you raise and lower the volume."
Now that's an exciting prospect. I may not get to
ride in a Lincoln LS and I probably won't be watching many movies on my computer, but a
home-theater system that's smarter than I am -- what a concept!
...Wes Phillips
wes@onhometheater.com
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