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Dolby - Making films sound better for over 40 years

AVForums gets a guided tour of Dolby’s cinema facility in Royal Wootton Bassett

by Steve Withers Nov 30, 2012


  • If there’s is one name that’s become synonymous with film sound over the last forty years it’s Dolby or, to use the company’s full name, Dolby Laboratories.
    The company was founded in the UK in 1965 by American Ray Dolby and was initially involved with professional recordings after developing their Noise Reduction system. Anyone who has ever owned a cassette deck will be familiar with Dolby NR but the company soon realised that their expertise in noise reduction could benefit filmmaking just as much as it did the recording industry.

    Dolby discovered that many of the limitations of the optical soundtracks on films were directly related to the significantly high background noise. The first film to benefit from Dolby Sound was Stanley Kubrick’s A Clockwork Orange which used Dolby noise reduction on all pre-mixes and masters. However Kubrick’s film still used a conventional optical soundtrack on its release prints, so the first film to actually use a Dolby encoded optical soundtrack was Callan in 1974.

    The following year Dolby launched Dolby Stereo, which combined their noise reduction system with additional audio channels using matrix encoding. The first film with a Dolby-encoded stereo optical soundtrack was Ken Russell’s Lisztomania in 1975, although it only used front LCR (left, centre and right). The first film to use Dolby Stereo with encoded surround channels was A Star Is Born in 1976 but it was Star Wars the following year that, in the mind of the public, forever associated Dolby with film surround sound. The success of that film helped cement Dolby Stereo as the dominant film sound system for the next 15 years until the advent of the digital age.

    In 1992Batman Returns became the first film released with a Dolby Stereo Digital soundtrack, although the name was quickly shortened to just Dolby Digital. Whilst rival digital sound systems were also launched in the early nineties, Dolby stayed ahead of the pack by evolving Dolby Digital over the years. In 1999 Dolby launched Dolby Digital EXwhich took the discrete 5.1 channels of Dolby Digital and added a rear centre channel using the same matrix technology originally developed for Dolby Stereo. Perhaps rather appropriately, the first film to use EX encoding was Star Wars: The Phantom Menace.
    But it was Star Wars that, in the mind of the public, forever associated Dolby with film surround sound.

    Despite numerous advances in technology, film soundtracks were still mixed and released in 5.1 and it wasn’t until the release of Toy Story 3 in 2010 that a fully discrete theatrical 7.1 surround system was launched with Dolby Surround 7.1. The delay in taking this inevitable next step in the commercial arena, long after it had been deployed domestically, was due to the transition to digital projection in cinemas, which took priority.

    However now that age of digital cinema is upon us, there is an opportunity to take sound to the next level and hopefully match the advances being made on the picture side in terms of digital capture, large format film, 3D and high frame rates. As a result Dolby is now in the process of beta testing and then launching Dolby Atmos, their revolutionary new sound system, which is designed to make cinema sound truly immersive.


    Although Dolby moved their head office to San Francisco in 1976, there are still a number of key locations in the UK, especially at Royal Wootton Bassett. Here on the outskirts of a quiet market town in Wiltshire, Dolby run a state-of-the-art facility which handles cinema and broadcast sales, preview support, screening support and training. Guy Hawley, who recently took part in our podcast about next generation sound systems, was kind enough to give AVForums a guided tour of the facility and also to provide a demonstration of Dolby Atmos.

    As soon as you arrive at the reception you are reminded of Dolby’s illustrious film history, with film posters adorning the walls and technical BAFTA and Emmy awards prominently on display. Once inside the facility the incredibly high level of security is the first sign that the latest Hollywood blockbusters are being worked on in the mastering suites, which was obviously the only area where we weren’t allowed to take photographs.


    The first port of call was the Mix Training Room, where Dolby helps train television sound engineers in how to mix Dolby Digital 5.1 for live broadcasts. The entire facility has a Centralised Application Room (CAR) which can feed broadcast material, either live or pre-recorded into the mixing suite, allowing the engineers to learn how to effectively mix 5.1 on-the-fly, as well as downmix to stereo. The room employs a classic 5.1 setup and has been used to train engineers working on a variety of different live broadcasts but predominantly Sky Premiership football and MotoGP.

    For those that are interested in the kind of equipment used in professional facilities, the speakers are M&K studio monitors - although Dolby is of course manufacturer agnostic. Next to the Mix Training Room is the AV Edit Room, which again uses a classic 5.1 layout, although this time the studio monitors are made by Genelec. The AV Edit Room is used for editing material to be used in training, for internal promotion and for external marketing and it includes all the major editing software such as Premiere Pro, Avid and Final Cut Pro.


    The Critical Listening Room is set up like a classic home cinema demo room and is used for checking new codecs and conducting blind listening tests. In this room, the speakers being used are again manufactured by Genelec and the processor is purpose built in the US. This isn’t the only hardware that Dolby makes, the also produce the PRM 4200, a 42” monitor made especially for professional grading. The monitor uses a commercial LCD panel but has a backlight composed of an RGB array with 4,500 local dimming zones. However before anyone gets too excited, one of these babies will set you back about $40,000.


    The Central Apparatus Room (CAR) is the main video and audio hub from which content can be sent anywhere within the facility via a local area network. There are multiple satellite decoders to stream broadcast material as well a video and audio stored on hard drives, allowing Dolby’s engineers to create an entire broadcast chain. On the film side there is also a complete suite of Dolby encoders, current and legacy, allowing any audio format to be piped around the facility.

    There are also Digital Cinema masters stored there, although these are locked off on a separate network that uses military grade encryption and can only be accessed in the mastering suites, which are in another highly secure area with CCTV coverage. These mastering suites are where the final mixes are completed and the quality control conducted. These final mixes can include adding foreign language dubs or subtitles to the Digital Cinema Package (DCP), which can then be duplicated.


    A DCP is a specialist hard drive designed specifically for use with digital cinema servers. These hard drives were originally designed for military use but have since been adopted by digital cinema for their hard wearing and reliable characteristics. The drives are shipped in protective hard cases via a special DHL courier service to the cinema, although they can also be delivered usung dedicated satellite links or high speed Internet connections. If delivered physically, Dolby use unmarked colour coded boxes that indicate whether it's a film or that week’s Pearl & Dean advertising.

    The colour coding is a throwback to the days when reels would be delivered to the cinema, a blue box is a film, whilst green or black boxes are advertising. However even with the DCP, the cinema cannot play the film without the Key Delivery Message (KDM) because AES encryption is applied to all the files. The KDM is transmitted via email to the cinema and is a file containing decryption keys that can only be used by the appropriate DCP. A KDM is allocated to each film and defines the start and stop period of validity for the projection of that particular feature.
    The colour coding is a throwback to the days when reels would be delivered to the cinema, a blue box is a film, whilst green or black boxes are advertising.

    The ultimate destination of the DCP is the Integrated Media Block (IMB) and dedicated server of the projector in your local cinema. We were able to see a typical Digital Cinema setup in the projection booth of Screening Room 2. An IMB is basically a board placed in the head of the Digital Cinema projector which processes the decoding and decrypting of digital images transmitted via the server and DCP.

    The implementation of the IMB radically changed the management of digital image projection in cinemas, moving the decoding and decrypting of digital images from the server to the projector and also adding an anti-piracy watermark in the content to be screened. Screening Room 2 is designed for quality control checking and some development work and it uses a Barco 2K projector with a full Dolby Surround 7.1 cinema sound system.


    Finally there is Screening Room 1 which is a fully equipped Atmos theatre with 35mm, 2K and 4K projectors and every Dolby audio format both current and legacy. Screening Room 1 is one of only three Atmos equipped theatres currently in the UK, the other two being Dolby’s screening room at their Soho offices and the Empire Leicester Square, both of which are in London. Screening Room 1 is the main cinema facility at Dolby's Royal Wootton Bassett offices and it is used for screenings, quality control, testing, development and even video conferencing!

    It's other key role is to provide demonstrations of Dolby Atmos, which of course was one of the main reasons why we were there. So join us again for our second article, where we will discuss Screening Room 1 in more detail and give you our first impressions of Dolby Atmos.

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