Enter the world of
Enter the world of
Dolby Film Sound
Dolby Film Sound
Throughout Dolby’s history, the company
has focused on a single mission: to develop
technologies that improve sound recording
and reproduction. When Dolby entered the
motion picture business in the early 1970s,
a new era in sound technology was born.
Since then, Dolby film sound formats have
evolved to provide the finest possible motion
picture experience. But the real success of the
formats lies in the beginning-to-end service to
the industry provided by Dolby Film Sound
Consultants who give technical support and help
to filmmakers, mixing studios, laboratories,
distributors, and cinemas.
1989 Academy
1989 Academy
Award of Merit
Award of Merit
for continuing
for continuing
contribution
contribution
to motion
to motion
picture sound
picture sound
A.M.P.A.S.
©
What is a Dolby soundtrack?
All Dolby film sound formats are backwardscompatible, enabling cinemas to play films to
the standard to which they are equipped. Both
the analogue and digital soundtracks are on
the same piece of film, providing the most
cost-effective and practical way of making
superb audio available to every cinema. The
tens of thousands of cinemas worldwide
equipped for Dolby Digital playback can
deliver this superb digital sound to their
audiences without needing extra disks or
different inventories.
Light from two
separate sources
shines through
the analogue and
digital soundtrack
areas
Direction of film
through projector
Analogue
sound signal
Digital sound
signal
Light-sensitive
devices convert
transmitted light
into electrical
signals
Lenses in projector
sound reader capture
and focus the projected
soundtrack image
Sound reader (in the projector)
Co-developed and co-owned by Dolby Laboratories and
Lucasfilm THX, the Dolby Digital Surround EX format was
developed in 1998 to provide sound mixers with greater
flexibility in creating film soundtracks.
The format is an enhancement of the Dolby Digital
format and adds a third surround channel to improve the
positioning of the surround effects (such as front-to-back
panning of sounds) and allows the ambient sound
reproduction to be more uniform throughout the cinema.
The format still uses the same digital data blocks between
the sprocket holes and remains fully compatible with the
Dolby Digital 5.1-channel system. The optical transfer and
laboratory printing process remain identical, so using this
format incurs no extra costs. Cinemas installed with
Dolby Digital Surround EX decoding equipment are able
to re-create the three surround channels, thus adding the
extra realism and excitement this format offers to an
audience.
In 1986, Dolby Laboratories introduced a new professional
recording process called Dolby SR (Spectral Recording).
This was used on the analogue soundtrack on 35 mm film
to provide more than twice the noise reduction, plus a
wider frequency response and lower distortion than its
predecessor, Dolby A-type. As with Dolby A-type, Dolby SR
is a mirror-image encode/decode process where the encoding takes place in the mixing studio and the decoding in
the cinema.
A Dolby SR soundtrack features four channels with left,
centre, and right speakers behind the screen, and a single
surround channel used for ambiences, atmospheres, and
special effects. Because there isn’t enough room for all
four channels to be printed separately, Dolby matrix
technology adds these four channels together to be printed
on the 35 mm film as two channels, known as Left total
(Lt) and Right total (Rt). The cinema decoding equipment
(Dolby Cinema Processor) then re-creates these original
four channels, using advanced matrix decoding technology,
and feeds the sounds to the appropriate loudspeakers.
Introduced in 1992, this system uses Dolby’s powerful
audio coding technology to fit 5.1 channels of high-quality
digital sound into the space between the sprocket holes on
35 mm film, enabling the digital soundtrack to co-exist
with the analogue soundtrack.
The improvements over analogue sound offered by Dolby
Digital apply not just to loud dramatic effects (like crashes,
explosions, and aircraft passing overhead) but in much
subtler ways such as:
•
clearer positioning of sounds at all times
•
cleaner dialogue
•
more lifelike atmospheres and quiet effects
•
more accurate musical reproduction.
Dolby Digital delivers five full-range channels (Left,
Centre, Right, Left Surround, and Right Surround), and
also provides a separate Low-Frequency Effects (LFE)
channel for reproduction through a subwoofer. Because of
the limited frequency range of this channel, it is referred
to as “.1” when describing the Dolby Digital 5.1-channel
format.
Dolby SR channel layout
Dolby Digital channel layout
Dolby Digital
Dolby Digital Surround EX
Surround EX channel layout
Dolby SR
CENTRELEFT RIGHT
MONO SURROUND
CENTRELEFT
SUBWOOFER
RIGHT
LEFT SURROUND RIGHT SURROUND
LEFT
SURROUND
CENTRELEFT
SUBWOOFER
RIGHT
RIGHT
SURROUND
BACK SURROUND
Pre-production meetings
Producing a film with a high-quality, multichannel Dolby
soundtrack should be planned from start to finish. Our
international team of Sound Consultants can discuss any stage
of the production process, from location and music recording,
through studio postproduction and film printing, to cinema
exhibition. Our Consultants can be reached by phone or email
and are happy to answer any queries.
Arranging the contract
A production company wishing to make a film with a Dolby
soundtrack must first enter into a straightforward standard
Motion Picture Service & Worldwide Trademark &
Standardization Agreement with Dolby Laboratories. To start
the process, the following details should be faxed to the
Wootton Bassett office (44 1793-842111):
•
production company contact details
•
film details (title, running length, format, etc.)
•
mixing studio to be used
•
expected date of the mix.
As soon as we receive the signed agreement and fee, the
authorisation to use Dolby equipment is sent to the appropriate
studio for this specific production.
Our Motion Picture Service & Worldwide Trademark &
Standardization Agreement details
•
services provided by Dolby Laboratories (for which a fee is
payable before the start of the mix) and clarification of
responsibilities
•
correct usage of the Dolby trademarks and logos (for which
no fee is due)
•
technical specifications for the soundtrack.
Selecting a mixing studio
Dolby Laboratories maintains a current list of all studios
worldwide approved to produce Dolby film soundtracks. These
studios have met the high specifications of acoustics and
equipment, calibration and alignment required to produce a
Dolby soundtrack. They provide an environment in which a
director can produce a soundtrack that will play back around
the world as faithfully as local cinema conditions allow.
Dolby equipment has been installed in the approved studios to
provide the encoding and decoding needed for the creation of a
Dolby film soundtrack. Use of this equipment by the studio is
permitted only after a film production company has completed the
Service Agreement, as detailed in “Arranging the Contract” above.
The studios should be contacted directly for their rates and
availability.
Mastering a soundtrack
Dolby Sound Consultants should always be present at the studio
for the final stage of a mix, when the printing master is
generated. This is normally a mixdown from individual
dialogue, music, and effects premixes and, if necessary, small
technical and artistic changes can be made at this time. For a
Dolby Digital or Dolby Digital Surround EX mix, the Dolby
encoding equipment in the studio produces a Magneto Optical
(MO) disk containing both the six-track digital mix and the
two-track analogue mix.
Dolby Sound Consultants check the alignment of the mixing
studio’s acoustics and equipment before the printing master is
made, and can offer technical and creative advice for the best
use of the Dolby film formats. This process also allows our
Consultants to become familiar with the mix, which is
invaluable if tests and checks are necessary later in the process.
Film mixing studio
Optical transfer
A current list of approved optical
transfer facilities is available from Dolby
Laboratories. We provide information
and training to these facilities in order
to maintain Dolby requirements and
procedures. Camera operators must
coordinate with the printing laboratory
to establish correct density matching
before the film soundtrack is transferred.
Once this has been established, the
transfer itself should be relatively
straightforward and a Dolby Sound
Consultant is not normally required to
be present. For a Dolby Digital film, the
optical transfer is made from the Dolby
MO disk produced in the mixing studio.
Optical sound camera
Training programme for approved installers
To achieve Dolby’s target of establishing a worldwide set of
replay standards for film sound, it is vital that every cinema is
aligned to the same high specifications. All our sound decoding
equipment (Dolby Cinema Processor) is sold to cinemas through
approved installers. Each year, Dolby invites these installers to
attend training courses covering all aspects of the installation
of cinema sound systems, from the Dolby processor itself to
room acoustics.
At the cinema
After support from Dolby through the postproduction, printing,
and distribution phases of producing a new film, the final stage
is to ensure that the audience fully appreciates the filmmaker’s
vision and receives the best possible presentation of the film in
the cinema.
Dolby Consultants are normally involved in important
screenings such as premieres
and press screenings, to verify
and optimise replay conditions, assist with the rehearsal
of the screening, and provide
backup support during the
screening itself.
Consultant aligning cinema
Assistance at festivals
Dolby Laboratories has long provided technical assistance at
film festivals around the world. Such screenings are very
important to many first-time filmmakers and seasoned
professionals alike. Our Sound Consultants are there to provide
technical support, ensuring the films are presented under the
best possible conditions.
Cinema advertising
Dolby is the one company that can provide cinema commercials
in digital sound, enabling advertisers to reach their audience in
the finest cinema conditions. The technology within the
cinema processor automatically switches to the correct format
when a Dolby Digital commercial is playing, thus ensuring that
the audience benefits from the same superb sound quality and
can enjoy an entire film presentation in Dolby Digital.
As with feature films, all cinema commercials must be contracted
with Dolby Laboratories. At many studios, this can be arranged
directly, through a simplified and quick procedure. Again, we
can provide an up-to-date list of studios approved for mixing
Dolby cinema commercials.
For several years, Dolby Laboratories has been researching the
subject of excessive loudness, especially in film commercials
and trailers. With Dolby’s guidance, industry bodies and
cinema commercial sales houses have now implemented
regulations to ensure the audience does not suffer from
uncomfortably high-volume sound. For current information on
worldwide standards, please contact the Film Department at
Dolby Laboratories in Wootton Bassett.
Dolby Digital Double-Head
Screening Service
With most mixing studios currently working with digital
dubbers, we now offer a service for playing back mixes in
any cinema directly from digital dubbers.
This service is ideal for special presentations of mixes-inprogress for clients, festival screenings, and audiencereaction screenings, and is run by Dolby Consultants who
also verify the alignment of the cinema and the equipment
before the film screening
is rehearsed. The use of
digital dubbers for these
screenings eliminates the
need for expensive transfers to magnetic tape and
the rental of large, bulky
magnetic playback units,
while providing higherquality audio in any
chosen cinema.
Digital dubbers
Controlling the soundtrack quality
at the printing laboratory
Laboratories printing Dolby Digital soundtracks must have the
Dolby Quality Control (QC) system installed. This software
analyses many of the printing parameters of the digital data
blocks between the sprocket holes on an entire reel of film and
provides a report on its findings. The laboratory can use this
tool to identify any problems and quickly correct them, plus,
a print-out of the QC report sheet can always be available for
the customer on request. QC
systems should be maintained
and checked by Dolby
Consultants to ensure their
accuracy; we are always
pleased to assist with technical
printing questions or problems.
QC software
Testing the soundtrack at Dolby Laboratories
Given sufficient notice, Dolby Consultants will check or analyse
a print in Dolby’s own Wootton Bassett screening room facility.
They can provide both a technical report on all quality issues by
using the analysis tools installed in the lab, as well as artistic
and subjective feedback by listening to the mix in the screening
room itself.
Print Checking Service
With so much investment made by film exhibitors to ensure
their audiences enjoy excellent digital sound and a bright,
clean picture, it’s only natural that the distributors also
want to supply high-quality prints to each and every
cinema.
Our Print Checking Service is designed for film distributors
to ensure that bulk prints from the laboratories are all of
the highest quality. This is performed by technicians with
experience of quality presentation in both film production
and exhibition. Print checking may be done either at the
Wootton Bassett screening room or at the printing
laboratory’s own screening room. After check prints have
been approved, random
samples are taken from
the bulk prints, and
both image and all
soundtrack formats
tested and analysed for
flaws or complications.
Problems with the bulk
printing can quickly be
detected and rectified
by the laboratory
before prints leave for
the cinema.
Film trailers
The Motion Picture Service & Worldwide Trademark &
Standardization Agreement signed by the film’s production
company also covers a film trailer soundtrack mix, which must
be in the same sound format as the feature film itself. There is
a fixed fee for Dolby Digital trailers that covers the necessary
transfer costs. The Film Department at Dolby Laboratories in
Wootton Bassett should be contacted for further information
about the transfer procedures. If a Consultant is required to
attend the mixing studio, this is charged as quoted in the
Service Agreement.
Foreign language versions
Every film originally produced with a Dolby soundtrack can be
remixed into any foreign language. The local Dolby Consultant
provides the same technical services with the same level of care
and attention, and seeks to ensure that the foreign versions are
an exact match of the original soundtrack. Our comprehensive
network of Sound Consultants, covering almost all corners of
the globe, is detailed on the back page.
A separate Motion Picture Service Agreement must be completed
for each additional foreign language version produced with a
Dolby soundtrack. The fee for additional languages is lower
than for the original version.
DISTRIBUTION
DISTRIBUTION
EXHIBITION
EXHIBITION
PRODUCTION
PRODUCTION
FILM SOUND
GLOSSARY
FILM SOUND
GLOSSARY
4:2:4 Matrix
A Dolby technology that enables a
four-channel L, C, R, S mix to be
matrix-encoded to two channels to
be transmitted either by film,
broadcast, video, etc. The original
four channels are re-created after
matrix decoding.
5.1 Mix
A six-channel Dolby Digital
discrete mix. The “.1” is used for
the sixth channel, as the LFE
channel has a limited bandwidth
up to 125 Hz.
Cross-Modulation Test
A test signal recorded on optical
film to ensure the correct density
match between a sound negative
and a print, thus producing a
correct reproduction of a studio
print master.
Cyan Dye Track
A new development in optical
sound printing that eliminates the
need for the problematic silver
redeveloping process. To be played
correctly, the soundtrack requires a
red LED soundhead on the
projector.
Discrete Mix
A term used for the Dolby Digital
mix that uses six (often called 5.1)
discrete audio channels.
Dolby AC-3
The multichannel coding
technology used on Dolby Digital
film soundtracks, DVD, and
broadcast applications.
Dolby Digital
A high-quality, six-channel (often
called 5.1) audio system using
Dolby AC-3 coding technology.
With a high degree of
transparency and data rates as low
as 320 kbps, Dolby Digital is used
for applications including 35 mm
film soundtracks, DVD, and
broadcast.
Dolby Digital Surround EX
The technology co-developed and
co-owned by Dolby Laboratories
and Lucasfilm THX that adds a
third surround channel in the
cinema while retaining
compatibility with regular Dolby
Digital channel systems.
Dolby Noise Reduction
The signal processing system that
reduces the inherent noise in
recording media without affecting
the sound. Dolby A-type and,
subsequently, Dolby SR were
originally used on commercial
music recordings and later on film
soundtracks. Dolby B-type, C-type,
and S-type were designed for the
consumer audio cassette.
Dolby SR
(Spectral Recording)
The most powerful analogue Dolby
recording system, currently still
used on film soundtracks, offers
greater noise reduction and a wider
frequency range than Dolby A-type.
Domestic Version
The original language soundtrack
of a film, often used in comparison
tests with a foreign language
version of the same film.
Double Head/Sep Mag
The practice of running a separate
reel of magnetic film containing
the soundtrack in sync with the
optical film containing the picture.
Often used for special screenings
before a married (combined) print
is produced.
Dubbing Studio
See Mixing Studio.
DVD (Digital Versatile Disc)
A domestic release medium widely
used for feature films. Dolby Digital
is the standard audio format used
with options for each disc to
contain multiple language versions.
Effects
Sound effects, i.e., the non-musical
elements on a soundtrack other
than dialogue.
Film Platter/Tower
Equipment used in the cinema to
join separate reels of film together
for continuous play through a
projector.
Final Mastering
The mixing stage at which all the
separate elements and premixes
are mixed together to produce the
printing master recording that is
sent to the optical transfer stage.
Foley
Sound effects, such as footsteps,
rustling clothes, traffic noise, etc.,
recorded by specialists during the
postproduction sound-dubbing
process. (Named after one of the
first such specialists.)
Hi 8
An eight-track DAT master, as used
by the Tascam DA-88 and Sony
PCM-800 machines. For film
mastering, the track layout is often
L, C, R, Ls, Rs, SW, Lt, Rt.
High Magenta Track
A method of printing optical
sound that enables correct
playback on both white light
readers and red LED readers on
projectors. The track is still
redeveloped, but uses a different
colour balance to accommodate
both light source wavelengths.
LEQ (Loudness Equivalent)
Measurement
A method of measuring the
perceived loudness of a section of
audio material. The Dolby Model
737 LEQ meter uses time averaging
and frequency weighting to
produce an LEQ(m) measurement
of film sound.
LFE (Low-Frequency Effects)
The channel used for sounds such
as explosions that are fed into the
subwoofer loudspeaker. Often
referred to as a “.1” channel,
hence Dolby Digital 5.1.
Lt, Rt (Left total, Right total)
A four-channel L, C, R, S mix,
matrix-encoded to two channels to
be transmitted either by film,
broadcast, video, etc. The original
four channels are re-created after
matrix decoding.
M & E (Music & Effects)
An original film soundtrack that
has had all dialogue removed
before being distributed to foreign
language studios for a new
language dub to be added.
Married Print
A film print that contains both the
picture and the sound, i.e., the
sound negative is “married” to the
picture negative onto the same
piece of print film.
Mixing Studio
A special theatre equipped for
mixing film soundtracks. These
rooms contain the necessary Dolby
encoding and decoding equipment
and are calibrated and aligned to
meet Dolby specifications and
standards.
MO (Magneto Optical) Disk
A computer disk used in Dolby
Digital mastering equipment to
record both the six-track mix and
the Lt, Rt mix. The whole soundtrack is therefore mastered onto
this one disk which is then sent to
the optical transfer stage for the
sound negative to be produced.
Optical Sound Camera
Equipment used to transfer the
printing master from the mixing
studio (normally a Dolby MO disk)
to an optical sound negative. The
sound camera exposes the raw
sound negative stock using a
combination of light from LEDs,
valves, and/or laser.
Overlaps
A short section of sound from the
beginning of a reel added to the end
of the previous reel. Due to the offset
between picture and sound on the
print, this must be done to ensure
there are no gaps in the sound
when the reels are joined together.
Premix
A mix (usually six or eight tracks)
containing only one of the three
elements of a soundtrack
(dialogue, music, or effects).
May be used to produce stems (see
below) or the final printing master.
Printing Master
The master tape of the final mix
produced in the mixing studio and
sent to the optical sound camera.
For Dolby Digital, this takes the
form of an MO disk.
Pro Logic
4:2:4 matrix technology, when
applied to domestic formats such
as video, broadcast, and DVD.
Pullups
see Overlaps.
QC (Quality Control) System
A software-based system used in
film laboratories to analyse the
print quality of Dolby Digital data
blocks and provide a summary of
all parameters.
Release Print
The actual film played in the
cinema. A release print consists of
reels approximately 20 minutes
long which are played
consecutively without interruption,
either by alternating between two
projectors, or by splicing the
individual reels together into one
large reel mounted on a film
platter.
SPL (Sound Pressure Level)
A measure of the loudness of sound
at a particular point in an
auditorium. All cinemas and
mixing studios are aligned to the
same SPL to ensure the audience
hears the film soundtrack at the
level the director intended.
Stems
Final stage premixes, fully
balanced and positioned, which
still contain the individual
elements (music, dialogue, and
effects) separately. Stems are
combined to produce the final
printing master and other delivery
requirements.
Stereo Variable Area (SVA)
A matrixed stereo optical
soundtrack used in the Dolby
analogue formats. The variable
area for each matrixed track is
used to change the amount of light
passing through the film to the
sound head on the projector. Two
independent variable tracks are
used for the Lt and Rt signals,
which are then decoded to become
Left, Centre, Right, and Surround
channels.
Subwoofer (SW)
The loudspeaker used to reproduce
the signal from the low-frequency
effects (LFE) channel.
THX
A technical specification for the
entire playback environment,
picture and sound, regardless of
film format.
X-Curve
A standard replay characteristic
that makes it possible for cinemas
of different sizes to sound similar
by compensating for the different
reverberation characteristics.
The Sound of a Great Picture
The Sound of a Great Picture
DOLBY’S INTERNATIONAL FILM SOUND CONSULTANTS
Alex Hudd
UK
adh@dolby.co.uk
Anirvan Ghose
India
ag@dolby.co.uk
Bhaskar Pal
India
bp@dolby.co.uk
Bruce Emery
Australia
be@dolby.co.uk
Carlos Klachquin
South America
cbk@dolby.com
Francis Perreard
France
fp@dolby.co.uk
Graham
Edmondson
UK
gce@dolby.co.uk
Jaume Puig
Spain
jap@dolby.co.uk
Hubert Henle
Germany
hh@dolby.co.uk
Jae Kyung Kim
Korea
jkk@dolby.com
James Seddon
UK
jps@dolby.co.uk
John Iles
UK
ji@dolby.co.uk
Julian Pinn
UK
jpp@dolby.co.uk
Kate Wu
China
kw@dolby.co.uk
Keith Fawcett
UK
kf@dolby.co.uk
Mario Faucher
South America
mjf@dolby.com
Mark Kenna
UK
mak@dolby.co.uk
Michael Denner
UK
mjd@dolby.co.uk
Max Puccio
Italy
mp@dolby.co.uk
Nick Watson
UK
nrw@dolby.co.uk
Norbert Zich
Germany
nz@dolby.co.uk
Ricardo
Viñas Sanz
Spain
rvs@dolby.co.uk
Richard Welsh
UK
rjw@dolby.co.uk
Sittiporn
Srisanguansakul
Thailand
sxs@dolby.co.uk
Steve Murphy
Australia
sm@dolby.co.uk
Vi. Kishore
India
vk@dolby.co.uk
Vikram Joglekar
Italy
vj@dolby.co.uk
For further information, please visit www.dolby.com
Dolby Laboratories, Inc.
• Wootton Bassett, Wiltshire SN4 8QJ, England
Telephone (44) 1793-842100 • Fax (44) 1793-842101
For information related to Dolby Film Services in the United States, please contact the Los Angeles office:
Dolby Laboratories, Inc.
• 3601 West Alameda Avenue, Burbank, CA 91505-5300, USA
Telephone (1) 818-823-2800 • Fax (1) 818-557-0890
Dolby, Pro Logic, and the double-D symbol, are registered trademarks of Dolby Laboratories. AC-3 and Surround EX are trademarks of Dolby Laboratories.
All other trademarks remain the property of their respective owners. © 2001 Dolby Laboratories, Inc. W01/001
Michel Monier
France
monierm@
dolby.co.uk
Dominique Schmit
France
schmitd@dolby.co.uk
Pavel Stverak
Czech Republic
stverakp@dolby.co.uk
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