General
What is SDDS?
Sony Dynamic Digital Sound® (SDDS®), is the film industry's most advanced
digital sound format. In developing
SDDS, Sony applied its experience in professional and home audio to give the
movie-going audience the highest quality sound presentation. SDDS is provided by Sony Cinema Products
Corporation (SCPC)¾a Sony
Electronics company¾which has
the mission of supplying the cinema exhibition industry with advanced
technologies and products. SCPC is
headquartered in Culver City, California, (within the Los Angeles area) with a
European office located in London, England. Why did Sony develop SDDS?
A central part of Sony's business is to improve the way
people listen to and enjoy sound. Sony
has developed the best in audio recording technology with innovations such as
the compact cassette, the audio tape and the compact disc. In recent years, Sony has expanded its
business into the production of quality software for both music and film. With Sony's venture into Hollywood and its
commitment to the motion picture industry, Sony has also chosen to apply its
expertise in digital audio to improving the cinema experience. How is SDDS different from other digital film sound formats?
While all digital soundtrack formats offer audible
improvement over the analog formats of a few years ago, the SDDS system is
superior in its ability to deliver the highest quality. SDDS excels over other formats in several
areas; the number of channels, its built-in digital redundancy, and its audio
coding technique. While the other formats have a maximum capacity of six
channels, SDDS can accommodate eight.
SDDS uses a data reduction technique known as ATRAC that delivers
excellent quality while keeping each recording channel truly discrete. When these elements are brought together
under the renowned Sony name, the audience hears a presentation that cannot be
duplicated by any other digital format. Why
eight channels and how are they used?
The expanded loudspeaker configuration
has its roots in the widescreen Cinerama and 70mm formats of the 1950 and
1960s. These used five full range
loudspeakers behind the screen and a single surround channel giving the
audience six channels. Variations
economized by not using the Left Center (LC) and Right Center (RC) screen loudspeakers
but used their film tracks for split or stereo surrounds (LS and RS). Although the addition of the stereo surround
and sub-woofer channels was an improvement, the loss of the LC and RC screen
loudspeakers created problems for sound engineers who wanted to create a
sweeping sound to fill the larger screens.
Today, SDDS with five screen loudspeakers, two surround channels, and a
sub-woofer channel takes the best of 70mm sound and returns the missing LC and
RC loudspeakers. What is
the difference between SDDS and THX?
SDDS is a
digital soundtrack format, which involves both the recording in the studio and
playback of digital sound in the theatre.
THX® is a certification program and consulting service that advises
theaters primarily on quality amplifiers, loudspeakers, and proper room
acoustics. THX certification is
independent of the film's format.
Theatres who conform to specifications and recommendations by THX use
their logo to identify conformance to these standards. Any manufacturer's sound system that
conforms to THX standards is frequently identified as a THX Sound System. Does SDDS
have a consumer equivalent for DVD and Laserdisc?
SDDS is a
professional format intended only for the motion picture theatres. Its
eight-channel configuration, with five loudspeakers behind the screen, would be
inappropriate for smaller 5.1 channel home systems. Sony intends to keep SDDS
as an exclusive experience for the movie theatre. In fact, both competing formats put the exhibitor at a
disadvantage in that their home versions have higher performance than their
professional systems. While the DVD
specifications have provided a designation for a potential SDDS bit stream,
Sony has no current plans to develop a consumer version of SDDS. What about Surround EX ?
Surround
EX is a joint development of Dolby and THX that adds a Back Surround channel by
incorporating an analog matrix decoder with the Left Surround and Right
Surround tracks. Technically, Surround EX is not a new film format but rather a
minimal enhancement to the existing 5.1 channel loudspeaker configuration. The analog matrix technique, much like
Dolby’s Pro Logic for consumers, is compatible with all digital formats
including SDDS. Dolby and other
companies have announced external analog matrix decoders that can be added to
any existing digital system. SCPC is
working with filmmakers to better define what they would like in surround
channels. If it is apparent that
additional channels are desired, Sony will likely incorporate surround enhancements
in future products. Sony feels that
rather than an analog matrix system, the industry would benefit from a fully
discrete and digital approach. Is there a
version of SDDS for 70mm and special venue applications?
For many
years, the use of 70mm has been winding down due to its high print and handling
costs, however an occasional film is released in 70MM. Recently there has been discussion of a
limited return to 70MM for special venue formats and for larger screens. SCPC is closely following the trend in 70MM
releases and is evaluating if a dedicated 70mm SDDS format is justified. Why are
directors and sound designers insisting on SDDS releases?
The
filmmaking community is insisting on SDDS because of its sound quality. Filmmakers have always been driven to
improve the look and sound of their creative efforts. Just as cinematographers seek out better lenses and better
photographic processes, the sound designers want to use the best technology to
reproduce their work. For the
Exhibitor
What equipment is required to play SDDS soundtracks?
SDDS playback hardware is straightforward. An SDDS processor, the DFP-D3000 is
installed in the theatre sound rack.
The SDDS reader unit, the DFP-R3000, mounted on the top of any standard
projector, reads the digital audio information on the film. Platter systems only require one SDDS reader
while dual projector changeover systems require two. Which
distributors have released films in SDDS?
SDDS
soundtracks are being provided by virtually all major film distributors
including Buena Vista, Columbia Pictures, Dimension Films, DreamWorks SKG,
Miramax Films, New Line Cinema, Paramount, Polygram, TriStar Pictures,
Twentieth Century Fox, Universal Pictures and Warner Bros. Where can
I purchase SDDS equipment?
SDDS can
be purchased through leading cinema equipment supply companies. In some cases, larger theatre chains can
purchase SDDS equipment directly from SCPC provided they have their technical
support staff trained in SDDS installation and maintenance. Unless the theatre chain is purchasing a
large number of systems and has ample technical staff, it is usually more cost
effective to purchase the SDDS equipment through an independent cinema supply
organization. Overseas customers are
encouraged to purchase SDDS through a local qualified company who can supply
immediate assistance with installation and follow-up service. How can I promote the SDDS system in my
theatre?
Since
today’s film-going audience seeks the best sound technology, it is highly
beneficial to advise patrons when showing a film in SDDS. To assist, SCPC has
camera-ready artwork for newspaper ads.
Each SDDS system comes with two complementary SDDS logo trailers (flat
and scope) to open the show. In
addition, SDDS theatre plaques, promotional posters and lobby publicity
materials are available upon request. Does SDDS have a characteristic sound?
Industry professionals frequently regard SDDS as the most
"accurate sounding” digital format, primarily due to its genuine discrete
digital coding technology and its ability to reproduce up to eight
channels. The goal of any soundtrack
format is to reproduce the film's sound mix to the cinema audience precisely as
it was heard in the film's mixing facility.
SDDS, with its discrete channel coding provides an exact one-to-one
reproduction of the mix as approved by the film's director. One digital format uses an aggressive
compression scheme to reduce the data so it can fit between the sprocket holes
and can produce audible side effects with some program material. Is
it always necessary to install more loudspeakers with SDDS?
No, SDDS
can be installed in conventional stereo theatres with perfectly acceptable
results. Eight channel films will be
reproduced correctly as the extra two screen tracks (LC and RC) will be
"folded" into the existing three screen loudspeakers. No sound elements will be missing because
all dialog, music, and effects will be reproduced accurately with the only
audible difference being the apparent width and evenness of sound spread across
the screen. While three screen
loudspeakers will sound very good, five loudspeakers will sound even better. Does it
take a large auditorium to hear the benefits of five screen loudspeakers?
Not
necessarily, much of the benefit of eight channels has little to do with screen
size but instead is related to the sound delivery capability of five screen
loudspeakers instead of three. When used with a dynamic action film five screen
loudspeakers will sound fuller, richer and will deliver impact without the frequently
heard irritation of sounding “too loud”.
Are all
SDDS films mixed with eight channels?
No, but
large action films with complex sound designs are often utilizing the extra
channels. Not all mixing facilities are
equipped with eight-channel monitoring and recording capability, and some films
simply don’t justify their use. It is
important to remember, however, that if the film is recorded with only six
channels, the quality heard in SDDS installations still exceeds that of other
digital formats. Are more
eight-channel cinemas being built?
A growing
percentage of cinema complexes are featuring eight-channel sound in their
auditoriums. In the early days of
multiplex construction, many were built with small screens and narrow shoe box
designs where three screen channels were sufficient. Fortunately, in the 1990s there is an increasing emphasis on
improving the quality of the presentation and a return to larger and wider
auditoriums. Can I play SDDS prints on other digital
film sound equipment?
No, each of the digital formats requires its own playback
equipment and therefore the various theatrical digital systems are not cross
compatible with each other. Prints with
SDDS soundtracks can only be decoded by SDDS playback equipment. Do I need SDDS if I have already installed other digital
equipment?
Today, most major-market theatres are equipped with at least
one of the digital formats. However
having any digital sound is not enough, as only SDDS provides the highest
quality. A growing number of films are
being released with eight channel mixes and SDDS is the only format that will
reproduce the original mix with all channels. In addition, the audience is
recognizing the SDDS logo as the most desired symbol of quality cinema sound. Do I need to specifically request SDDS prints?
In North
America, the majority of films are released “single-inventory” with SDDS
soundtracks and no action is required.
In overseas territories, please let your local film distributors know
you have installed SDDS equipment. Where
on the film does SDDS put the digital soundtrack?
SDDS is a sound-on-film system with the
digital information printed in two continuous strips along the film's
edges. (Other digital formats either
put the sound information in blocks between the sprocket holes or on a separate
CD-ROM that is synchronized with the film.)
Sony chose the sound-on-film approach because of its inherent
simplicity; no discs to become lost and requires no external synchronization system. The location on the film was chosen because
it provides the highest amount of continuous data recording space. In fact, the outer edges provide roughly
four times the data capacity when compared to alternative schemes that use the
area between the sprocket holes. The
extra information is used to improve both the sound quality and soundtrack
reliability. Do SDDS
prints wear out?
Repeated tests—both in the laboratory
and in the field—have proven that the SDDS soundtrack, when played on a typical
projector with normal maintenance, will outlast the useful life of the release
print. All digital soundtracks, as well
as the analog soundtrack and image are subject to scratch and wear damage if
the projector is not properly maintained.
How is the SDDS soundtrack protected
against routine scratches and wear?
The SDDS
data is recorded on the cyan layer, which is three emulsion levels below the
film's surface. SDDS uses an ingenious
strategy of cross redundancy to ensure error-free replay in the theatres. Simply explained, each side of the film contains
the backup information for the track on the opposite side of the film. Damage on one side of the film is
automatically corrected by the backup information recorded on the other side. Furthermore, the data on the two sides are
offset in recording time from each other by about 17 frames so a splice across
the entire film will have no effect on the sound. The analog soundtrack is used
as a last resort backup in the unlikely possibility of both sides of the film
having suffered critical damage. For
the Film Distributor
Does SDDS
increase film distributors’ print costs?
It is
SCPC's objective to provide the highest quality digital soundtrack on every
print at no additional expense to the exhibitor or the distributor. Since the SDDS soundtrack is recorded using
the same photographic processes as the picture, there should be no inherent
increase in print or distribution costs.
However, as with any other digital format, there are investments
required by the laboratories and this could affect print costs. In overseas territories, the distributor may
choose to import SDDS prints from the U.S., and this could also increase print
costs. We view these as temporary
situations that will be resolved as more overseas laboratories become equipped
to make SDDS negatives and release prints. Can other
digital formats be printed on the same 35mm print?
Yes, since
each of the new digital formats uses a different physical location on the
release print, all the formats are physically compatible with each other. That is, one format will not obstruct the
other. To record multiple digital
soundtracks on the same release print, it is necessary to record all formats on
the same sound negative. That requires
using a transfer facility with an optical sound negative recorder having
multi-format capability. How many
theatres are equipped with SDDS ?
As of early 1999, over 6,750 theaters
are equipped with SDDS. Current data on
theaters equipped can be obtained from SCPC.
What is
being done to increase SDDS screens overseas?
Limitations
in non-U.S. sales has been the result of a short supply of local films titles
with SDDS soundtracks. Overseas films,
especially those with foreign language soundtracks, require local negatives to
be made and relatively few film facilities have the necessary recording
equipment. Currently, negative
recording facilities are located at Pinewood Studios and Technicolor (U.K.),
LTC (France), Image Film (Spain) and Cinecolor Laboratories (Thailand). In order to increase the supply of SDDS
films, a new generation of recording equipment is under development for 1999
delivery. What is
involved in foreign language releases of SDDS films?
As with any foreign language release,
replacement dialogue must be recorded and mixed with the original music and
effects tracks. In addition, films may
be edited to satisfy local regulations.
Foreign language releases require a new sound negative to be recorded
for local release prints. (Subtitled
prints, even if made locally, frequently use the U.S. domestic soundtrack
negative.) The replacement sound
negative is ideally recorded and processed by a local facility. If a local SDDS sound negative facility is
not available, it's possible to record the negative elsewhere if sufficient
time is allowed. Are
subtitles a problem with SDDS prints?
Distributors
should be aware of the specific sub-title processed used. Some older sub-titling processes use an acid
to etch away the film emulsion. As with
any other soundtrack format, it is critical that no residual acid be allowed to
touch the SDDS track. If the digital
track is protected by wax, it is critical to completely remove the residual
wax. The overlay and laser subtitling
methods present no problems at all. (To
print overlay subtitles, the laboratory must be equipped for printing SDDS.) For the Technician/Installer
What equipment do I need to purchase to play SDDS?
The Sony DFP-3000 cinema processor that is the central
control element in the modern sound rack.
The DFP-3000 processor contains SDDS decoding, analog soundtrack
decoding, along with precise 1/3 octave digital equalization for room and
loudspeaker tuning. Will SDDS work with all types of projectors and sound
systems?
Virtually any projector can be equipped with SDDS. The SDDS reader unit attaches to the top of
a projector. Unusual projection systems
can be upgraded to SDDS using special adapter plates. SDDS works with any existing power amplifier and loudspeaker
system. Of course, overall sound
quality is also determined by the quality of power amplifiers and loudspeakers
used and therefore high quality equipment should be used. What
special test equipment is required to install an SDDS system?
The SDDS
installation requires a Windows® PC-type laptop computer and SDDS
setup software, which provides improved accuracy and faster setup. Installing an SDDS playback system is much
like the installation of any other digital systems and other commonly available
setup equipment is used. To ensure that
systems are properly installed and calibrated, SCPC holds frequent training
courses for cinema technical staff. Is it possible to move the SDDS
equipment into another auditorium?
The DFP-3000 is the central component in the sound rack and
therefore moving for screen to screen is not recommended, as specific adjustments
need to be made for each screen. |