This
page has been updated with corrected 2022 links. |
The
SURROUND 2001 CONFERENCE sponsored by Surround Pro Magazine,
was held at the Beverly Hilton Hotel in Los Angeles on December
7 and 8, 2001.
Reading like a mini who's who in audio,
a slew of producers, engineers, acousticians, film editors,
recordists, mixers and assorted scientists gathered in a smallish,
rather intimate setting (there were 28 booths and 6 meeting
rooms) to discuss the particulars of Surround Sound.
Only the third annual show of its type,
it brought together in a convenient and accessible format a
series of experts lecturing to a series of experts - a busman's
holiday of audio intelligentsia, as it were.
There are a number of critical issues that
seem to surface every time we talk about the evolution of stereo
into surround sound. Not unlike the evolution of mono into stereo,
the finer points of mixing, panning, bass management, speaker
placement, movie theater vs home theater, disc formats and the
alphabet soup of formats themselves, from THX
to DTS
to Dolby
to LFE, to SACD
to DVD,
to DVD-A
and so on, became the critical issue of the day.
While some of these topics might seem simplistic
in retrospect, say, 20 years from now, I assure you that they
are of utmost criticality right now, and large sections of the
industry seem to hang on every word spoken in some of these
seminars.
For instance: for years, stereo panning
for the home pop recording market has used two channels, the
Left and Right. The center image is totally phantom, obtained
by panning essentially a mono signal to be the same strength
in the Left and the Right speakers, and psychoacoustically we
think there is an auditory image in the center.
With the various surround sound formats,
we now have a true center channel speaker to work with.
Do we pan evenly between all three speakers? Do we set up dual
panpots to pan between Left and Center and then from Center
to Right? Or do we place the center sound in the center speaker
only, and feed "a little reverb return" to the Left
and Right speakers? Or do we hope the consumer has the system
set up properly in his or her home, and we feed some balance
of signal to all three speakers? And if we mix it that way,
what will it sound like when it is "folded down" into
stereo? Will we have to do a completely separate mix for a "stereo
CD" release and then do a separate mix for a "DVD-Audio"
release?
Speaker placement is another hot topic.
Starting with the ITU suggested specifications of stereo placement,
(which has been slightly modified/embellished by the AES PDF
HERE) and adding to that various recommendations
from Dolby and THX, and adding to that the real-world setups
that professional engineers somehow "fall into," we
have a series of guidelines that have been stretched almost
to the breaking point. At face value, each of the systems and
setups makes sense - or seems to.
Then someone comes along and suggests or
explains in great detail why the other system is kind of "wrong".
Some of these systems do play well together.
Dolby and THX coexist just fine on the playground, but everyone
has an explanation of why you should or shouldn't use dipole
surrounds, and perhaps in another
paper I'll expound on this. At least it was agreed upon,
more or less, that the technically correct way to set up the
LCR speakers is to have them (more or less) each the same distance
from the sweet spot, which can be defined as an arc (more or
less) the radius of which is drawn from the listener's nose.
At least nearly everyone agrees on 80 Hz
as the crossover freq between the mains and the subwoofer(s).
Since there are MILLIONS of homes which have a receiver/control
center with THX circuitry in it, and that circuitry crosses
over at 80 Hz, if you are doing a studio mixing session and
you want to hear the mix the way your target audience hears
it, then you should use 80 Hz as the crossover frequency. True,
in special and certain instances there may be reasons why exactly
80 isn't right. Too high a crossover frequency, and you run
the risk of hearing the bass directionality. Too low a frequency
and you lose all the benefits of proper bass management, which
include increased dynamic range from the mains (satellite speakers)
and less dopplering of the mid frequencies by the low freq drivers.
The ubiquitous acronym LFE is yet another
issue. Originally designed for film use only (!) for increased
headroom in the optical channels, somehow this effects/extension
channel is being used / abused by music mixers trying to squeeze
every last dB of sound into every last molecule of track headroom
and dynamics, which brings up another problem, namely "FF
distortion". Recent papers presented at AES have shown
that most CD players can be in a permanent state of distortion
when reproducing new album releases. How is this measured? And
what do we do about this after we measure it?
And now, by 2022, this has turned into
what much of the industry incorrectly calls "loudness
wars" which REALLY are LEVEL WARS. You can play any LEVEL,
whether -10dBV or -1dBV at 95 dB in your home. You can play
any level at 70 dB in your home. You can play any level at
110 dB in your home: that's why you have a VOLUME CONTROL.
To balance out the show we had proponents
of other psychoacoustic delivery systems on hand to give their
viewpoint, from the people at SRS Labs (now owned by DTS) to
Richard Elen on Ambisonics.
The late Vincent Van Haaff of Waterland
Designs (wayback machine link here)
spoke on the acoustic factors you should take into consideration
when designing a studio / control room / monitoring environment
for surround sound, while Art Noxon from ASC
discussed setting up Tube Traps specifically to enhance surround
speaker setups, in a combination called "Attack Wall".
Bob Michaels of 5.1 Entertainment spoke
about the basic differences between DVD formats, and how different
authoring software is necessary to complete a project so that
whether the disc is played on a DVD-V player, or a DVD-Audio
player it will have the correct menuing system appear. This
is apparently a rather large bottleneck in the production of
DVD's, and has opened up a whole new field of software and production
called menu authoring.
The late John
Eargle discussed the new realm of microphone setup and technique
for surround sound recording.
Tom
Holman gave his historical perspective and dropped hints
about the future of the industry.
A lively discussion was had with Joe Bates
of the CTA/CES moderating
on whether or not the typical consumer can hear the difference
between Dolby Digital 5.1 and DVD-Audio; and of course this
only raised a hundred other questions such as the technical
setup and validity of the test, how was the original material
recorded and monitored, and so on.
There were two sessions concerned with film;
one was about mixing surround for film in the theater, hosted
by Chris Jenkins of Universal Studios, and the other was about
mixing film audio for DVD presentation in the home, which requires
a whole different set of rules and assumptions, moderated by
Bob
Margouleff, Brant Biles, and Steve Parr.
To round out the format wars Bruce Botnick
and Frank Fillipetti hosted a discussion about SACD
and DSD.
Bobby Owsinski from Surround
Associates and Surround Professional Magazine lectured on
System Calibration and Bass Management, explaining how in the
real world of studio setups sometimes the hard and fast rules
have to be bent a little bit, while in another session, recording
studio managers from around the country were discussing the
requirements and hardships of owning and booking a recording
/ mixing facility which has specifically been designed for surround
sound work. John Kellog from Dolby Labs discussed interfacing
with the artist and making the artist and musician aware of
the technical /creative oppportunities that surround mixing
has to offer.
The Steinberg Producer group, partnered
with DTS, discussed their views on the innovative new NUENDO
digital audio workstation and how it is used as a creative production
tool. Industry luminaries such as Greg Ladanyi, Elliot Scheiner,
Phil Ramone, Chuck Ainley, Ed Cherney, and Alan Parsons gave
their views.
A panel of car audio experts discussed the
latest in car surround, and what technical breakthroughs or
setup adjustments make the car environment different from the
home environment.
In another room, the world of 5.1 as it
relates to the HDTV spec was being discussed. Various methods
and procedures for setting up, feeding, and mixing multiple
audio sources to multiple audio destinations were explained.
And now, rather than have me ramble on endlessly
I'd suggest you read all about it right from the source. SMR
group (Stuart M. Robinson) has put together a beautiful site
and explanation of the show which you can find HERE.
|