Dolby Atmos has been promising for a few years now that it would be the next big thing in surround sound. But what exactly is it and why is it still relatively unknown? We take a look at Dolby Atmos and the future of surround sound.
Chances are you’re yet to experience Dolby Atmos. Despite the sound technology having been around since 2012, it’s yet to take off in a big way. But the technology is becoming increasingly prevalent, with more and more cinemas embracing it, and the AV industry providing home Atmos systems. Sky has even added Atmos support to its Sky Q service.
Until you experience it for yourself, though, allow us to be your guide to this next-gen audio technology.
What is Dolby Atmos?
Developed in 2012, Atmos expands the previous 5.1 and 7.1 setups to include numerous speakers which are placed around a room to create an all-enveloping, “3D” sound experience.
In a cinema setting, where the technology was first introduced, up to 64 speakers will not only be placed in front of, and at various points around you, but also above you. This adds a height dimension to the sound, creating a hemisphere of speakers which allows film-makers and sound designers to direct specific sounds to certain areas in the room with a high degree of accuracy.
Related: Dolby Vision on TV
One of, if not the main thing to be aware of when it comes to Dolby Atmos is the concept of audio objects. Previously, sounds were constrained to specific channels – portions of the audio which get routed to particular speakers.
With Dolby Atmos, sound designers don’t have to limit a sound to a particular channel. They can specify where an individual sound originates from and moves to, and the Atmos system will interpret that data and play it back within a virtual 3D space.
The result is sound that feels as though it’s coming from the room you’re sitting in. Rain drops can be heard hitting individual leaves close-by, helicopters sound like they’re flying right above you. Individual sounds that are no longer limited to a particular speaker or channel in this way are known as audio objects.
Related: Best surround sound systems
With Atmos, a foundation level of sound is still mixed using the traditional channel-based approach. These will be the ambient, static sounds which don’t require pin-point specific placement. On top of that layer, the ‘audio objects’ will be placed, along with their respective spatial metadata, to create a much more dynamic sound experience. The technology allows for up to 128 audio channels, 10 of which will be used for the base layer, leaving 118 for the audio objects.
Using object-based audio also means the sound data can scale across multiple formats. 64 speakers is the best way to render the Atmos soundscape, but that doesn’t mean other, less elaborate setups can’t reproduce the same audio experience. In that sense, it’s not so much about the number of speakers, but the principle of audio objects and how they can be reproduced across various systems.
Whether you’re listening in a cinema with a giant 64-speaker setup, or at home with only seven speakers, or even using headphones, all the necessary data is there for the 128 audio objects to be played accurately, making the technology incredibly adaptable.
So where can I hear Dolby Atmos sound?
The easiest way to hear what Atmos is all about is to find a cinema that’s been upgraded with the necessary technology. Unfortunately, in the UK, most cinemas are yet to make the jump. But, there are a number that have, and you can use the Dolby Atmos website to find your closest one. At the time of writing, there are five Dolby Atmos theatres in London, and several others scattered about the country, mostly in larger cities.
Related: What is HDR?
With such a paucity of Atmos theatres, your other option is to upgrade your home audio setup. Of course, when it comes to upgrading your personal system, 64 speakers is a logistical challenge at best, and utterly crazy at worst.
As a result, numerous solutions have been introduced to try to bring Atmos sound into the home.
Dolby Atmos at Home
Even though you won’t be able to recreate the full cinema 64-speaker setup at home, you can still get a pretty good Dolby Atmos experience in your living room. Home Atmos systems are capable of reproducing all 128 audio objects across as little as seven speakers. For those who want to go all out, home Atmos systems support up to 34 speakers, but such a setup is, shall we say, unnecessary.
But before you worry about speakers, there’s some other information to be aware of. Firstly, you won’t need a new Blu-ray player. Standard Blu-rays are capable of containing the necessary Atmos data, as are Ultra HD Blu-rays, so unless you feel like upgrading to UHD Blu-ray, there’s no format issues to worry about. You can even get certain movies broadcast with an Atmos soundtrack, if you have a Sky Q subscription.
However, at the moment the broadest range of Atmos content is available to digitally stream from services such as Netflix via built in Smart TV apps and streaming boxes like the Apple TV 4K.
Related: What is Ultra HD Premium?
What you will need is an AV receiver capable of decoding Atmos sound. There are now quite a few options available, from the 11.2-channel , to the 7.2-channel Denon AVR-X1200W.
Once you’ve got the receiver, it’s time to think about speakers. You can buy the usual home cinema packages which include the speakers and an Atmos-capable receiver, but if you’re upgrading your current setup, you’ll be pleased to know that your existing speakers can be used as part of the process.
The Onkyo TX-NR3030 features an Atmos decoder
So, what about those crucial overhead speakers? If overhead sound is one of the key features of Dolby Atmos, you may be wondering whether you’re going to have to drill holes in your ceiling in order to install the requisite speakers. Luckily, that isn’t necessary. Here, you’ve got two options.
Firstly, you can buy specially designed Dolby Atmos speakers. These integrate forward-facing speakers with upward-firing versions, which rebound the sound off the ceiling, mimicking the effect of overhead speakers.
If you like your current speaker setup, there are also modules available which will transform existing speakers into Atmos-enabled versions, capable of throwing the sound upwards. It’s simply a case of placing the modules, which are essentially just upward-facing speakers, on top of your existing speakers to add the overhead functionality. The excellent KEF R Series and Q Series both feature these matching Atmos modules.
Secondly, you can take the plunge and install actual overhead speakers. As mentioned, home Atmos systems will work with up to 34 speakers, so if overhead speaker installation isn’t a problem, you can go Atmos mad. Before ruining the plasterboard though, it’s worth bearing in mind Dolby’s guidance which states that using only two overhead speakers will ‘provide a convincing and powerful effect’, while four overhead speakers will give you ‘the optimum sense of audio movement and precision’.
In fact, Dolby’s reference guides for the best Atmos speaker setup recommend using only 12 speakers at most. Basically, once you’ve got the right AV receiver, you can upgrade your existing 5.1 or 7.1 surround sound by adding two or four ceiling speakers and either a couple of speaker modules or Atmos-enabled speakers.
There is one other option for those looking for a less complicated alternative to the full surround sound experience: Atmos-enabled soundbars. These simpler solutions integrate upward-firing speakers with traditional soundbar tech to deliver an Atmos experience without the hassle. The Samsung HW-K950 comes with two dedicated rear speakers and delivers full Dolby Atmos for around £1299.
At CES 2018 we also got the chance to try the Sennheiser Ambeo 3D Soundbar prototype, which takes the Dolby Atmos codec and adds Ambeo 3D processing to create a seemingly more immersive experience.
Related: Best soundbars
Samsung’s HW-K950 integrates Atmos technology into a soundbar
Atmos on Mobile
Because Dolby’s new sound tech is designed to be adaptable, you can even listen to Atmos sound using your smartphone or tablet, and headphones.
Atmos on mobile is made possible by combining traditional virtual surround technology with the object-based audio of Dolby Atmos. Without going into the history of virtual surround sound, the combination of the two allows headphones to reproduce a convincing version of the 3D soundscape. It won’t be the same as sitting within a circle of speakers, but you should still get an improved sense of space and directionality.
Related: Best headphones
You won’t need a new pair of headphones to listen to Atmos sound, but whether you’ll need a new phone or not is surprisingly unclear. Dolby told Trusted Reviews that manufacturers can embed Atmos into both software and hardware, which means your device doesn’t necessarily need to have any kind of specific hardware to use the sound technology.
Dolby’s website says the following: “Dolby audio experts custom-tune every smartphone model featuring Dolby Atmos or Dolby Audio to get the most out of the device speakers and dramatically improve clarity and performance. The foundation of Dolby Audio is a set of technologies that use advanced audio formatting and signal processing to deliver enhanced sound.”
How does it stack up against the competition?
Dolby isn’t the only company getting in on the audio object action. DTS’s DTS:X format was introduced in January 2015 and also uses the object-based system. Unlike Dolby Atmos however, DTS:X was originally aimed at home use, before being targeted at cinemas.
How is DTS: X different? In many ways, it’s pretty much the same as Dolby’s system. The crucial difference is in the speaker setup however. Whereas Atmos supports up to 34 speakers in the home, 64 in a cinema setting, and requires new speakers to work properly, DTS:X supports up to 32 speakers and will work with your current home speaker setup.
That means that while extra overhead speakers will enhance the DTS:X experience, they’re not necessary to get the most out of the technology. What’s more, DTS:X is supported by a larger number of manufacturers, with many releasing firmware updates for existing AV receivers. Unfortunately, Blu-rays featuring DTS:X are currently in short supply, with only a handful of movies supporting the format having been released.
Another competing ‘object-based’ 3D audio system is Auro 3D. Developed by Belgium company Auro Technologies and officially introduced in 2006, the format is based upon a three-layer design: surround, height, and overhead.
The key difference between this system and Dolby Atmos comes down to the speaker layout. With Auro 3D, an additional row of speakers is placed above the traditional row found in 5.1 and 7.1 setups. This adds the height element. A single speaker is then placed on the celing to add the overhead dimension. This means
Although Auro 3D also creates a spatial sound field, the company doesn’t use the term audio objects as Dolby does. Auro’s plugins allow sound designers to dictate where sounds should originate and move to, and the format can be used in cinemas, at home, and over headphones, just as with Dolby Atmos.
Films such as Hunger Games, The Croods, and Red Tails have used Auro 3D, although it certainly isn’t as popular as DTS:X or Atmos. Interestingly, Auro, DTS, and digital cinema technology company Barco announced in 2013 that they would be teaming up to support an open format approach to producing object-based cinema sound, with the goal of allowing theatres to play movies on any new 3D audio format designed according to the open standard.
Sounds great, what can I watch/hear in Atmos?
Since Dolby introduced the new sound technology in 2012, numerous film-makers have opted to use it. The first ever film to use Atmos was Disney Pixar’s Brave, which premiered at the Atmos-equipped Dolby Theatre in Hollywood in 2012. Since then, Atmos has become increasingly popular. Dolby has a list of films that have used the technology and they’re available through services such as Netflix and iTunes.
Game of Thrones got the Atmos treatment
Not all of these films have been released with Atmos sound on Blu-ray however. Thankfully Dolby has also supplied full lists of Atmos Blu-ray discs for each territory.
Atmos and VR
With virtual reality still on the rise, 3D audio has never been more important. Recreating the way we hear sounds in day-to-day life makes all the difference to how immersive a VR experience feels.
Dolby has already worked with VR content creator Jaunt to add Atmos sound to three of the company’s VR experiences: Black Mass, Kaiju Fury!, and video from a Paul McCartney concert entitled Live and Let Die.
Related: What is virtual reality?
Since then, Atmos support has been extended to support virtual reality experiences on iOS, Android, OS X, and Windows. Dolby lists the Oculus Rift, one of the two big VR headsets to be released this year, the other being the HTC Vive, as a supported device on its website, as long as you have Windows 7 and above.
On top of that, the company says the Samsung Gear VR is compatible with Atmos technology. You can also get the Atmos experience when using Google Cardboard, the company’s foldable contraption that turns your smartphone into a VR viewer.
Related: Best Samsung Gear VR apps and games
Again, although neither Samsung nor Apple seemed to make a big deal out of their respective devices being Atmos-capable, it seems that most handsets are able to reproduce Atmos sound.
New dimensions of sound
So there you have it. Dolby’s latest surround sound format is an exciting proposition for anyone who cares about audio technology. Although Atmos is yet to appear in enough cinemas in the UK for most to experience it, the technology is now available in the home in a variety of forms. All of which means you can experience object-based audio right now if you’re curious enough.
As more and more manufacturers start supporting the format, and as virtual reality starts to take off, object-based audio is going to become even more important than ever, so keep an eye on our site for all the latest updates.