What is Dolby Atmos? All you need to know

Dolby Atmos was once an up-and-coming technology. Now it’s available across an array of devices and experiences, from cinemas to TVs and smartphones. But what exactly is it? Read on for all the details on Dolby Atmos.

Touted as the future of home cinema in 2012, Dolby Atmos has since been embraced in cinemas across the country. You can now enjoy that cinematic sound in your own living room, with numerous soundbars, AV amps, TVs and even smartphones supporting it.

What is Dolby Atmos?

Developed in 2012, Atmos expands 5.1 and 7.1 set-ups to include numerous speakers placed around the room and create an all-enveloping, 3D sound experience.

In a cinema setting, up to 64 speakers will be placed in front of, around, and above you. This adds the dimension of height to the sound, creating a hemisphere of speakers that allows filmmakers and sound designers to direct specific sounds to certain areas with a high degree of accuracy.

Probably 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.

Dolby Atmos

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. Raindrops can be heard hitting individual leaves, helicopters sound as though they’re flying above you.

Individual sounds that are no longer limited to a particular speaker or channel in this way are known as audio objects.

With Atmos, a foundation level of sound is still mixed using the traditional channel-based approach. These are the ambient, static sounds that don’t require pinpoint specific placement. The audio objects are placed on top of that layer, 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 are 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. The best way to render the Atmos soundscape is with 64 speakers, but that doesn’t mean other, less elaborate set-ups 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 set-up, 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.

Related: What is Dolby Vision HDR?

So where can I hear Dolby Atmos sound?

The easiest way to hear what Atmos is all about is to find a cinema upgraded with the necessary technology.

The other option is to upgrade your home audio set-up. 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.

Related: What is HDR?

Dolby Atmos at home

Even though you won’t be able to recreate the full 64-speaker cinema set-up at home, you can still get a good Dolby Atmos experience in the 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 set-up is 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 are no format issues to worry about.

Related: Best 4K Blu-ray players

The amount of content in the format has been growing too. Sky has been producing content in Atmos for some time now, with Premier League football and events such as the Isle of Wight music festival beamed to homes around the country in the format. BT has put its considerable weight behind the format. Every Premier League football match on its BT Sport channels is broadcast in Atmos, too.

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: Inside Sky’s Isle of Wight Festival broadcast in 4K Dolby Atmos

The Isle of Wight Festival is part of Sky’s Dolby Atmos programming

To get Atmos from a speaker package set-up, an AV receiver is required to decode Atmos sound. There are plenty of options available, such as Yamaha’s 9.2-channel RX-A3080.

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 set-up, you’ll be pleased to know that your existing speakers can be used as part of the process.

Related: What is 4K TV and Ultra HD? All you need to know about 4K

So, what about those crucial overhead speakers? You may be wondering whether you’re going to have to drill holes in your ceiling to install the requisite speakers. Luckily, that isn’t necessary.

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 set-up, there are also speaker modules available which will transform the existing set-up into Atmos-enabled versions capable of throwing the sound upwards. It’s simply a case of placing the modules, which are essentially upward-facing speakers, on top of the existing speakers to add the overhead functionality. The excellent KEF R Series and Q Series both feature these matching Atmos modules.

Related: What is Ultra HD Premium?

Dolby Atmos

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 that Dolby’s guidance 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 set-up recommend using 12 speakers at most. 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.

The rise of Atmos in the home has also coincided with the rise of Atmos-enabled soundbars as a cheaper, less obtrusive way of getting Atmos in the home.

Dolby Atmos

These simpler solutions integrate upward-firing speakers with traditional soundbar tech to deliver an Atmos experience without the hassle. The Sony HT-ST5000 comes with upward-firing speakers and delivers Atmos for around £1200. Vizio, a US AV brand, has entered the UK market with very affordable options, bringing the barrier to entry further down.

Sennheiser’s Ambeo 3D Soundbar, which we saw back at CES 2018. It takes the Dolby Atmos codec and adds Ambeo 3D processing to create a seemingly more immersive experience. It sounds fantastic, but it’s also expensive.

Related: Best soundbars

Atmos on mobile

Because Dolby Atmos is designed to be adaptable to whichever device you’re listening to, you can experience Atmos sound using your smartphone, tablet or 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.

The Samsung Galaxy S10 supports Atmos sound

Dolby told Trusted Reviews that manufacturers can embed Atmos into both software and hardware, which means your device doesn’t necessarily need specific hardware to use it.

That means you won’t need a new pair of headphones, and a growing number of Atmos-compatible smartphones have hit the market in recent times, including the Apple iPhone XS, OnePlus 7 Pro and Samsung Galaxy S10.

Related: Best headphones

Music in Dolby Atmos

Atmos isn’t just for home cinema aficionados. Its presence has been growing in the music industry too.

The first Blu-ray audio disc with Atmos sound arrived in 2015 in the 25th anniversary edition of R.E.M’s Automatic For The People. That sector has grown since with Hans Zimmer’s Live in Prague concert film released with Atmos audio, as has INXS’ reissue of the Kick album, Roger Waters’ The Wall and many other titles.

Dolby Atmos

Credit: Hans Zimmer

At the 2019 Bristol Hi-Fi Show, Trusted Reviews was treated to a behind the scenes look at classic songs remixed in Atmos. Tracks included Public Enemy’s Don’t Believe the Hype (in orchestral form), the Beach Boys’ God Only Knows (by the Royal Philharmonic orchestra) and Elton John’s Rocket Man.

The end result was interesting, some songs are better suited to the format than others hence the orchestral versions of some songs being played, but the potential for what Atmos can do is there.

And music studios have picked up on this, with Universal Music Group announcing a partnership with Dolby to create music in the immersive format.

How does Dolby Atmos 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 the same as Dolby’s system. The crucial difference is in the speaker set-up, 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 set-up.

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.

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 set-ups. This adds the height element. A single speaker is then placed on the ceiling to add the overhead dimension.

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 The Hunger Games, The Croods, and Red Tails have used Auro 3D, although it 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.

Related: THX Ultimate Cinema has Dolby in its sights

Which films use 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.

Not all of these films have been released with Atmos sound on Blu-ray, however. Thankfully Dolby has also supplied lists of Atmos-enabled Blu-ray discs for each territory.

Related: Behind the scenes of Dolby Cinema at the Odeon Luxe Leicester Square

Atmos and VR

With virtual reality (VR) 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.

Since then, Atmos support has been extended to support VR experiences on iOS, Android, OS X, and Windows. Dolby lists the Oculus Rift and the HTC Vive as supported devices, 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 with Google Cardboard, the company’s foldable contraption that turns your smartphone into a VR viewer.

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.

Related: What is virtual reality?

New dimensions of sound

So there you have it. Dolby’s surround sound format is an exciting proposition for anyone who cares about audio technology.

We’ve seen manufacturers throw their weight behind the format, especially with soundbars supporting the format. Broadcasters have produced more and more content in Atmos, and as VR starts to take off, object-based audio could become even more important than ever.

Are you ready to jump in?

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