| Editorial October 2009
Too Much Information?
Audiophiles have long known that when an audio system gets
better, certain recordings can sometimes sound worse. The reason is that, by definition, a
"better" sound system functions at a higher level of resolution: it transmits to
the listener more information, more clearly and more accurately, revealing more of
what’s actually encoded in a recording -- for better or worse. Topnotch recordings
will sound better, but poor recordings will sound worse: you’ll now be able to hear
recording, editing, processing, and mastering flaws that were previously hidden under an
inferior system’s higher noise floor and/or colorations. Case in point: Any Rolling
Stones album from the 1960s or ’70s can sound wonderful on a low-resolution car
radio, but when played through a good home stereo, their high levels of distortion are
readily audible and make them sound dreadful.
The same sort of thing is happening with modern-day
home-theater equipment, both audio and video. It wasn’t long ago that most of us were
watching movies on standard-definition CRT televisions, playing analog VHS videotapes that
had about 240 lines of resolution and a limited color palette. The playback technology
didn’t approach the limits of the source material, which was usually film, so a lot
of information was getting lost. There’s much debate about just how much resolution
film has, not to mention that film doesn’t actually have lines (or pixels, for that
matter), but some good information is available. The International Telecommunications
Union performed a study on the subject and published a paper, "Image
Resolution of Theatrical Film in Theatrical Presentation," in 2004. Their goal
was to create an apples-to-apples comparison of the resolutions of film and video sources.
To make a long story short, they said that while a film negative can exceed the
equivalent of 2400 lines of video resolution, film stock is equivalent to about
1400 lines, and that, in their survey of movie theaters, what viewers saw ranged from the
equivalent of 685 to 875 lines (with an average of about 750 lines). But even the worst
movie theater presents much more information than does a videotape; as a result, VHS
videotape ended up obscuring much of the original image.
Standard DVD improved playback quality somewhat by offering
480 lines of resolution and better color accuracy, but the ITU study concluded that
SD DVD was still far from the resolution seen in even the poorest movie theater.
Again, the viewer wasn’t seeing everything.
 Current high-definition playback from
Blu-ray Disc, with its 1080 lines, progressive-scan, and better color support, has changed
all that. Blu-ray also natively supports playback of film sources at their original rate
of 24 frames per second, which SD DVD and videotape don’t. Whether you’re
watching a good-quality flat-panel LCD or plasma television, or a projector-based system
such as the one I have, there’s finally enough information presented so that you can
see most of what was on the original film stock while surpassing the performance of some
theaters. Along with that resolution, though, problems in the original film source and the
transfer to Blu-ray begin to become very noticeable -- something I began thinking about
when I watched the Blu-ray edition of the Sidney Lumet classic Dog Day Afternoon,
which was released to theaters in 1975.
The Dog Day Afternoon Blu-ray image reveals film
source material that appears to have been around the block a few times: poor color
accuracy, scratches, grain where there shouldn’t be. It’s like watching a
second- or third-generation film print at a mediocre theater. The age of the film
obviously contributes to the problem -- film stock deteriorates over time, and it’s
only in recent years that movies are being shot digitally, or are immediately converted
from film to a digital format in which they can be preserved, free of deterioration.
We’ve all heard about the meticulous remastering jobs done with certain films -- the
studio finds the very best print, digitizes it, then works through it frame by frame in
the digital domain, fixing any flaws. But was the best available print of Dog Day
Afternoon used to create this Blu-ray release? Was any attempt made to clean up some
of the imperfections? My point is this: The source material used to create the Blu-ray
edition of Dog Day Afternoon might have been acceptable for lower-rez video systems
because you couldn’t see as much -- VHS’s poor colors would probably have
overshadowed Dog Day Afternoon’s, and the scratches and grain would have
mostly been masked by the limited number of lines -- but today’s Blu-ray-based 1080p
systems are very good at revealing any flaws, so the source used has to be better.
It’s no surprise that the same thing is happening on
the audio side of video -- something audiophiles can relate to. A quality, high-resolution
surround-sound system can allow a great soundtrack to sound its best, but it will also
readily reveal flaws, making some soundtracks sound worse and more irritating than when
they’re played back on a lo-rez system that would mask such details. This is even
more relevant with hi-def encoding schemes like TrueHD: Everything comes through.
 There’s also something new and
surprising happening that, for me, first reared its head in the "Hips Don’t
Lie" chapter of Shakira’s The Oral Fixation Tour, a concert recording now
available on Blu-ray. I now use this chapter on the Blu-ray Disc to demonstrate to people
who come over to my place to experience and learn something about home theater just how
revealing a first-rate sound system is, and what the new challenges are for the sound
engineers working on these releases.
As the chapter begins, Shakira speaks to the audience,
introducing Wyclef Jean, who sings with her on "Hips Don’t Lie."
Shakira’s voice sounds breathy, which you’d expect from someone who moves as
vigorously onstage as she does; it also sounds splashy and thin. But the moment Shakira
starts to sing, the breathy, splashy qualities disappear, and her voice becomes quite
full, much clearer, and more isolated in space. Obviously, something has changed. But the
microphone didn’t change, nor did her position onstage -- or anything else, for that
matter. I can only assume that she either lip-synced the song onstage, and that what I
hear is the switchover to the pre-recorded vocal track -- or, more likely, Shakira
overdubbed her concert vocal track in postproduction to improve the sound for the video
release. I didn’t listen that closely to the other tracks to see if the same thing
occurs throughout the concert, but if it happens on one track, it’s safe to assume
that it probably happens on others, which is disappointing if you were hoping to
experience a performance that was recorded truly live.
The team who put this release together probably didn’t
anticipate that people might have systems of high enough resolution to notice this, or
thought they wouldn’t care. Or perhaps their own studio monitoring system wasn’t
resolving enough for them to detect it when they created it. But today’s best
home-theater sound systems are of high enough resolution that those who master these discs
should use mastering systems of at least commensurate quality, in order to produce
recordings that won’t leave consumers disappointed.
We’re at an exciting time for home theater -- 1080p
displays and surround-sound systems make possible a true movie-theater experience in your
own home, and never before have such high levels of picture and sound quality been
available for the home at such low prices. But while such high resolution can give you
stunning images and stupendous sound, it can also highlight flaws enough to irritate and
distract the viewer. When the CD was introduced, a disclaimer often appeared in the
booklets: "Because of its high resolution . . . the Compact Disc
can reveal limitations of the source tape." Maybe a similar statement needs to appear
on some of the hi-rez releases coming out on Blu-ray.
. . . Doug Schneider
das@hometheatersound.com |
