A three-dimensional cinema sound technology which has been used in many new Hollywood films is now being made available for home cinema systems.
Dolby’s Atmos technology creates realistic “sound objects” at specific points around the viewer, reflecting the action on screen. It can create the effect of cracking thunder in the distance or falling rain around the viewer, making the audience feel they are inside the action, the creators hope.
Gravity director Alfonso Cuarón described the new technology as “a dream come true, where you can explore the possibilities of depth and separation as never before”.
Atmos was launched in 2012 as the fifth upgrade to Dolby’s 39 year-old “stereo” surround sound product, and has since been hailed as “one of the most significant developments in the history of cinema sound” by Pinewood Studios.
The technology is designed both for cinemas and home cinema systems, with each piece of audio encoded as a sound object targeted at a specific point around the audience in a three-dimensional space. Up to 128 individual audio elements can be played at once by the system – a number only Gravity has come close to exploiting so far during a scene featuring hurtling space debris.
Cinemas need extra speakers in the ceiling
“We’re banking on great movies with Atmos soundtracks to make the upgrades tempting,” explained Jonathan Jowitt, Dolby Europe evangelist.
More than 100 films have already been made and released using Atmos, including Brave, The Hobbit, Iron Man 3, Gravity, Star Trek Into Darkness and Guardians of the Galaxy to name a few. Several UK cinemas, including Empire in London’s Leicester Square, have the technology installed.
Cinemas need ceiling-mounted speakers to demonstrate Atmos, and although home cinema enthusiasts could also install speakers in their ceiling, it is possible to improvise and create the same effect.
“Our research discovered that a sound appears to come from above a listener when it has a ‘notch’ – the combination of the sounds bending over your head to your ears as well as the reflections from your shoulders,” Jowitt told the Guardian.
Sounds without that “notch” appear to come from directly in front of a listener, rather than above. Dolby uses processing technology to build a system that could use speakers which instead of being mounted to the ceiling, bounce the sound off the ceiling to create the same effect.
The result is a virtual overhead speaker, created by directing a small speaker at the ceiling – and the difference between that and roof-mounted speakers is impossible to discern.
A cinema may have at least 36 speakers and a home system seven or eight, but Dolby uses the same rendering techniques to make the sound track fit the equipment and the room.
“All the audio from the film is just condensed to fit the speakers available using the same spacial coding as the cinema,” Jowitt explained.
One for the home cinema enthusiasts
People looking to upgrade their existing home systems to Atmos will need to buy kit including a new audio receiver, which decodes the sounds and spits them out to the speakers. Audio receivers less than two years old might be compatible with the Atmos software update, Jowitt explained, but the system will still require at least two “up-firing” speakers.
The good news is that the Atmos soundtrack can be squeezed onto a Blu-ray disc or into the existing Dolby Digital Plus technology used by streaming services including Netflix, which means an existing Blu-ray player or streamer should be able to handle it.
Jowitt acknowledged that the system is likely to appeal to home cinema enthusiasts rather than the average family, who are likely to make do with standard TV speakers or with the popular “sound bar” speaker.
Whether that is enough to get users to upgrade in the near future is unknown. The market is currently polarised with the home cinema enthusiasts on one side and normal users who make do with TV speakers or a simple sound bar.
More than 20 manufacturers including Denon, Marantz, Onkyo, Pioneer and Yamaha, have already licensed Dolby’s Atmos for home for a range of different devices, many set for release in September at the IFA electronics trade show in Berlin.
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