Surround
Professional 2003 Seminar:
“The History and Future of Surround Sound” -
Tom Holman, TMH Corporation
In
his Surround 2003 seminar, Tom Holman of TMH Corporation gave
an interesting, anecdote-laden account of the history of surround
sound recording, a “drama in five acts, we hope with
a happy ending.” Holman went back to the roots of stereo
recording to find the events that led to the first recordings
in surround sound. As Holman pointed out, it all goes back
to Bell Labs’ initial experiments with stereo recording
in the early 1930’s. Their initial brainstorming proposed
that a recording system be developed with an “infinite” number
of microphones deployed in front of the musicians, with just
as many playback speakers as there were original microphones,
deployed in an identical curtain in front of the playback listener.
They soon discovered that phantom imaging adequately cut down
the “infinite” number of channels originally posited,
and set up a live test transmission over the then unheard-of
bandwidth of 15kHz telephone lines in three-channel stereo
from the Philadelphia Orchestra conducted by Leopold Stokowski
at the Academy of Music in Philadelphia, to a listening room
that Bell Labs set up in a theater in Washington, D.C. This
deployment of the three channels was identical to the front
array of a modern surround system, with right, left, and center
channels. Although this relay was successful, an efficient
playback system for three-channel recordings eluded the Bell
engineers at the time, and the concept was shelved.
A few years later, Stokowski had a chance meeting with Walt
Disney in a restaurant in Hollywood, where they hatched the
idea of a motion picture cartoon that featured classical music,
a project that was to become ‘Fantasia’. Stokowski
was intrigued, and insisted that Disney’s engineers contact
Bell Labs to find a way to make use of their experimental stereophonic
recording system in the film. When Disney’s engineers
confirmed that this was possible, Disney challenged them with
an additional inspiration which hit him when thinking about
the ‘Flight of the Bumblebee’ segment of the film:
Wouldn’t it be great to have the musical sound of the
bumblebee flying all around the audience instead of just in
front of them? According to Holman, “Insofar as we
know, Walt Disney is the inventor of surround sound.”
Many techniques and pieces of equipment were invented for the ‘Fantasia’ project,
including overdubbing. The technique and end result were dubbed “Fantasound.” Disney’s
original concept was also remarkably close to the current surround
setup: right front, center front, left front, right rear, and
left rear, lacking only a modern subwoofer channel. The recordings
on the film soundtrack, though, where only three channel, with
the rear channels being “steered in” electronically
where desired, such as in the chorus entry in the ‘Ave
Maria’ section of the film. The requirements of outfitting
theaters to use Fantasound were, not surprisingly, a large
drawback. Disney sent a “road show” out with all
the equipment to demonstrate Fantasound in New York, Los Angeles,
and a few other places, but it didn’t receive wide enough
exposure to catch on. As World War II began, the equipment
was retired until Josef Stalin’s government in the Soviet
Union expressed an interest in using it for soviet films, which
he hoped to elevate as the new art of the people, replacing
the traditional central role of religion in Russian society.
As the U.S.S.R. and the U.S. were allies during the war, an
agreement was made and the equipment was loaded onto a ship
and sent to Europe – but somewhere in the North Atlantic,
the ship met a German U-boat which torpedoed it, sending Fantasound
down to the bottom of the ocean, where it presumably still
rests today. “Thus the end of the first act – our
hero dies an ignoble death,” Holman quipped.
After the war, there was an explosion of new technologies,
including television. To combat the huge dip in movie attendance,
around 1950, Twentieth Century Fox resurrected the concept
of “Cinemascope” for wide screen presentation of
films. They included stereophonic sound as part of the package,
here in a four-channel deployment (left, center, right, and
one mono surround channel). Other cinematic surround modes
were also tried, but the expense of prints, competing formats,
and the inability of the new technologies to recapture the
television audience led to the demise of usage of surround
sound in film, thus bringing the second act to a close.
The third act, Holman continued, arose from the hi-fi hobbyist
movement, which flowered in the Fifties and peaked in the Seventies.
The taste for higher quality sound led to frustration with
the phantom-stereo imaging of two-channel sound. The first
problem was the precedence effect, which is heard if you move
around the room between a pair of stereo speakers – the
apparent image moves with you, very unlike the way a genuine
sound continues to radiate from where it was actually made
by the musical instrument or singer. The other problem is that
this creates a frequency response problem, with certain frequencies
being cancelled out, causing an unbalancing ripple effect throughout
the audible spectrum known as “comb filtering”.
As Holman pointed out, the rush into Quadraphonic sound in
the 1970’s was not sufficiently thought out in terms
of psychoacoustics, let alone in terms of playback technology.
It was an attempt to create surround sound without fixing the
basic problems of front stereo imaging. Playback problems and
competing formats further guaranteed the failure of Quadraphonic
sound.
Not surprisingly, Holman cited Dolby’s pioneering of
theatrical applications of surround sound technology as Act
Four of the surround sound story, with the esthetic use of
the technology in the legendary film ‘Stars Wars’ as
the point where surround sound finally caught everyone’s
attention. He pointed out how small print in the original contract
guaranteed that all prints of the film would include Dolby
Surround sound, a fact that helped encourage theaters to update
their sound systems, as this was not always the case with prints
in the past. He also pointed out how the right and left side
channels of their six-channel array were used for low-channel
effects, thus introducing an early equivalent of today’s “.1” subwoofer
channel. Holman amusingly pointed out that the “.1” of “5.1
multichannel” is more a marketing concept than a reality.
Considering the percentage of bandwidth actually needed for
low channel effects, he said that it could more accurately
be described as “5.005 surround sound”.
We are now in act five of the multichannel drama, where it
is hoped that surround sound will live happily ever after – or
move on to future sequels. Holman pointed out that the current
standard is a compromise based on the idea of achieving surround-sound
with as few channels as possible, due to the size limitations
of film. Many have said that additional rear and side channels
would improve imaging and panning, but Holman admitted that
detailed charts of extensive audio testing by Swedish Radio
indicate the rapid drop-off in directional and frequency perception
in human hearing to the side and rear. The human ears are forward-focused,
and are not especially perceptive to discrete image focusing
behind the head. The point impressed is that the main leap
in multichannel recording has been made. It can be altered
or tweaked in the future for improvements, but the largest
leap in perception for the home listener is from two-channel
stereo, to the current 5.1 surround sound, but Holman stopped
short of embracing the current technology as a long-term plateau.
Holman commented that researchers have determined that it would
take a minimum of “tens of thousands” of recorded
channels to accurately reproduce a listening environment. Holman
instead suggests a maximum increase to 10.2 channels – “for
now.” This array would add left-front-wide and right-front-wide
channels at 60 degrees from the listener, a center rear channel,
and left and right front high channels to break the vertical
plane. The additional sub channel would be to create a greater
sense of headroom on the low frequency effects, making it possible,
for instance, to very accurately recreate the sense of space
and pressure one feels when suddenly entering an otherwise
silent cathedral. In closing, Holman noted that there is no
limit on how much surround sound can be improved by the addition
of further channels, but he pointed out, “the more
we add, the more confused people will get, and they already
think
we’re a bit crazy!”
Mark Jordan 04/01/2004.
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Surround
2003 Report Index
Last update:
27th February 2004
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