Object Based Audio (Dolby Atmos Installation) can be a little complicated to understand if you’re not a technician or really love your technical research. If all that ‘tech’ phases you then simply read the first and last paragraph of this post and let us do the rest; if however you love researching about the things you are going to put into your home cinema then you’ll really enjoy this article. So to put it simply Object Based Audio helps to make your home cinema sound really really good with amazing richness and depth. You feel like you’re truly inside the story, with sound coming from all directions, including overhead (feel free to skip to ‘Want to know more?’ at this point)!
Dolby – Commercial Cinemas
The first company to come to market with an Object Based Audio offering was, unsurprisingly, Dolby. As world leaders in cinema sound the company first introduced its Dolby Atmos system for use in commercial cinemas. The Dolby Atmos sound objects (a total of 118) are used in conjunction with the traditional surround sound set up that features 9.1 beds of audio (nine conventional channels plus one sub-bass channel), to give a total of up to 128 independent audio tracks.
Dolby Atmos Home Cinema Installation
Dolby then introduced a domestic version of Atmos, scaled down from the 64 speakers used in a cinema to a much more manageable number, typically seven, nine or 11 (although it is possible to use up to 34 speakers in a very large installation – 24 on the floor and 10 overhead).
The nomenclature for the domestic set ups follows the familiar 5.1, 7.1, 9.1 pattern established by conventional home cinema, but also indicates the number of ceiling/elevation speakers employed, e.g. 5.1.2 (five main speakers, one subwoofer and two ceiling speakers) or 7.1.4 (seven main speakers, one subwoofer and four ceiling speakers).
Hot on the heels of Dolby was a system developed by Belgium based Auro Technologies called Auro-3D. Again taking the standard 5.1, 7.1 format, Auro-3D enhances this with both height and overhead channels. The height information recorded during production is mixed into a standard 5.1 surround PCM carrier and the Auro-3D decoder extracts the signals during playback to recreate the height channels via speakers placed around the room at 30 degrees above head height. This configuration is referred to as 9.1 (five ear-level surround speakers, four height speakers and one sub-bass speaker).
A single overhead speaker (sometimes called the Voice of God speaker) adds an extra dimension and forms a link between the height layer speakers around the room for ‘fly-over’ effects. The nomenclature for the simplest system featuring this VOG speaker is 10.1. Adding an extra height centre channel speaker makes it into an 11.1 system and two additional rear surround channels make it 13.1.
An additional technology called AuroMax expands the basic Auro 11.1 and Auro 13.1 into “zones”, allowing placement of sound at discrete points around the wall or ceiling and within the three dimensional space, making it similar to the other object based audio formats.
The third variant of Object Based Audio comes from DTS in the guise of its DTS:X system. This differs from the other two systems in that it isn’t tied to a particular speaker layout and will work (to a degree) with existing simple 5.1 speaker systems.
In the cinema environment, the speaker array used for DTS:X is a hybrid of the Dolby Atmos and Auro-3D set ups, with a standard eight channel base layer, a five channel height layer and three rows of speakers in the ceiling.
During the post production for the movie, the sound can be placed in three dimensional space using DTS:X’s Multi Dimensional Audio platform, just like the Dolby Atmos system. The DTS:X soundtrack from a Blu-ray is then decoded by the processor according to the number of speakers connected to it and their position in the room, giving the best possible results for that particular speaker set up. This makes it truly backwards compatible with existing surround sound systems, but for the best results the additional height/ceiling speakers are going to be needed.
What’s required for Object Based Audio in the home?
Just like a traditional surround system you’ll need a Blu-ray player, processor and speakers.
Most of the major electronics brands are now incorporating Object Based Audio into their processors, particularly Dolby Atmos and DTS:X systems.
The speakers for the main channels can be identical to the ones used for standard surround systems.
The requirement for height speakers presents two possible options:
- install dedicated in-ceiling speakers
- use specially designed up-firing speakers
The installation of ceiling speakers is the potentially tricky part of an Object Based Audio system. In a new build property or renovation, it’s not an issue of course, but upgrading an existing surround system or installing a whole new Object Based Audio system in a ‘finished’ house with the need to install ceiling speakers can be problematic.
For that reason, it is possible to specify dedicated up-firing speakers that beam the height channel information from the walls up to the ceiling, where it is reflected back to the listening position, creating a very effective illusion of sound coming from the ceiling.
What content is available?
Originally the film companies were a little slow to respond to the opportunities of Object Based Audio and so content has been hard to come by. Fortunately this has changed now and the number of Blu-rays being offered with Dolby Atmos soundtracks is increasing all the time. For the latest list of films follow this link: http://www.dolby.com/us/en/experience/dolby-atmos/bluray-and-streaming.html
DTS:X movies on Blu-ray are listed here: http://dts.com/discover/dtsx-movies-at-home
The limited number of Auro-3D Blu-rays can been seen here: http://www.auro-3d.com/consumer/
For owners of existing collections of discs, the AV Receivers will convert existing surround sound tracks into pseudo Object Based Audio, providing a very effective soundtrack upgrade for legacy movie collections.
Want to know more?
If you are looking for inspiration, take a look at one of our previous home cinema installations here.
We are expert home cinema installers and would be very happy to talk to you about a Dolby Atmos home cinema installation. Based in Sevenoaks, Kent and only a short train ride from central London we are ideally based to cover installations in London, Kent, Sussex, Surrey and the rest of the South East. Please contact us and we can take you through our Object Based Audio products and explain the installation process in more detail, or alternately come and be our guest in our show cinema in Kent or Essex and experience it for yourself.