Dolby Atmos: Bringing It Home


This week, was invited to Dolby's London office to experience how its new sound format - Atmos - will work in the home.

We've experienced Dolby Atmos in the cinema before, with last year's demos and a handful of special film screenings (such as Oblivion, Godzilla, X Men: Days of Future Past and Gravity) showcasing just how immersive Atmos can be.

What is Dolby Atmos?

First, a brief explanation of Dolby Atmos. The idea is simple, yet clear: adding overhead sound to that produced by the existing surround system to create a dome-shaped soundfield, with effects whizzing above the audience's head in a realistic manner. It's an incredibly immersive experience.

Instead of being channel-based, Atmos is object-based, and this has made all the difference in how a film's soundtrack is created. It allows filmmakers to put a sound object anywhere they want in a 3D soundscape to create a more lifelike soundtrack.

Instead of being restricted to sending music, effects and dialogue to specific channels to invoke surround sound, engineers can now map an object's movement in space - an arrow whizzing, birds flying, leaves rustling, a character speaking - from point A to B and let Atmos work out the trajectory from speaker-to-speaker.

Atmos allows up to 128 individual sound objects in a mix, which also contains metadata about the type of object, its parameters and how it's meant to move around in a soundtrack.

The mapping happens in real-time, too, and most importantly to home cinema owners: Atmos is scalable.

Since it doesn't rely on channels, this means the metadata stored in an Atmos soundtrack can be adapted to any given number of speakers in a room.

Atmos in the home

Which brings us nicely to how Atmos works in the home. Dolby's newly-developed Spatial Coding technology is the brains of the operation here, which intelligently reads and adapts the metadata stored in a film's Atmos mix to the speaker configuration you have in your home.

All your need to do is tell your Atmos-equipped AV receiver the number of speakers you have and where they are in the room (not dissimilar to how you'd calibrate your current 5.1 or 7.1 AV system), and it will map the Atmos soundtrack around your speakers accordingly. It's that simple.

AV manufacturers have already got the ball rolling with bringing Atmos into the home theatre setting, with Onkyo, Pioneer, Denon and Marantz announcing new lines of AV receivers that will support it.

So you'll need a new AV receiver to reap the benefits of Atmos. But will you need to throw out your speaker package, too, and start drilling holes in your ceiling to get that overhead sound sensation? Not at all. Dolby acknowledges that not everyone will be able to install in-ceiling speakers into their homes to create the Atmos experience.

Their solution: upward-firing Atmos speakers that sit on top of your existing speakers and fire sound up to reflect off the ceiling and create the illusion of sound coming from above.

Dolby Atmos-enabled speaker modules by KEF

Dolby Atmos-enabled speaker modules by KEF

Onkyo is already offering free SKH-410 speaker modules with its new upmarket receivers, but the ones we viewed in the demo were manufactured by KEF (pictured above).

Dolby recommends adding these modules (or the in-ceiling speakers if you're able to go that route) in pairs for the Atmos soundtrack to travel consistently around your room.

It's an easy fit: they're designed to be compact and modular, and you don't have to move your speakers an inch to accommodate them. You can even place them on a bookshelf, as long as nothing obstructs the sound waves being beamed up to your ceiling.

The demo: how does Atmos sound?

Dolby ushered us into a modest living room-sized demo room, where a 7.1 system with Dolby Atmos-enabled KEF speaker modules and in-ceiling speakers were waiting for us.

We were shown the same clips as in the cinema room - a Leaf trailer (developed by Dolby with Pixar and was shown before the film Brave in cinemas), the intro chase scene from Star Trek: Into Darkness, a clip of Red Bull racers Sebastian Vettel and Mark Webber driving their F1 cars in a tunnel, and a couple of bespoke Atmos trailers. We weren't told at first if the clips were being played via the in-ceilings or the KEF modules (it was the modules all along), but the effect was fantastic.

We weren't expecting the huge scale you get in an Atmos cinema, but the sounds whizzing all around you, and the sense of immersion - it's all there. The upward-firing modules do a great job at making us believe that sound is coming right from above us, while integration across all speakers is seamless.

The tension and energy of Kirk and Bones running through the jungle is palpable and arrows seem to fly right at us and whizz past in a hugely exciting manner.

But it's the quieter, subtler moments - such as a sycamore seed being gently buffeted around by a breeze in the Leaf trailer - that really impressed us. It feels tangible; you can hear the rustling of leaves and wind going around you, not just around the edges of the room.

Switching between in-ceilings and the modules was interesting. Admittedly, the in-ceilings do give a stronger impression of overhead sound, but the upward-firing modules perform almost as admirably.

KEF module sitting atop a KEF R700 front speaker

KEF module sitting atop a KEF R700 front speaker

For those curious, here's a complete list of the products used in the Atmos home demo:

The 7.1 system consisted of seven KEF R700 speakers for the front, centre, surround, and rear channels, with two B&W CT SW15 subwoofers for the LFE channel (powered by a B&W SA1000 sub amp).

Two Onkyo PA-MC5501 amplifiers were used, one for powering the seven surround speakers, the other for powering the in-ceiling and Atmos-enabled speaker modules from KEF.

The source was a bespoke Dolby-produced Atmos software renderer running on a Windows laptop (for logistical reasons of switching between demo clips, speaker configurations and showing us the renderer interface).

Clips were shown on a 51in Samsung PS51D6900 TV; yes, our screen was a three-year old plasma telly with no hint of 4K Ultra HD, but we hardly noticed that it wasn't a giant 4K screen, as the Atmos soundtrack was captivating and entertaining.

Atmos Blu-ray discs

Some good news: Atmos Blu-ray discs will be available later this year in the run up to Christmas, while streaming content will also be available in Atmos next year.

Here's some even better news: the Atmos Blu-ray discs are backwards compatible. The current formats - Dolby TrueHD (for lossless Blu-rays) and Dolby Digital Plus (used by video streaming providers and on secondary language Blu-rays) - have been updated to support the Atmos film mix.

There's no need to update your Blu-ray player or stock up on new HDMI cables, as HDMI 1.4 specification fully supports Atmos. Dolby obviously recommends buying the Atmos Blu-rays when they come out, as you'll already have the content available if and when you do decide to upgrade to Atmos.

There's no word on pricing or names of titles yet, but we imagine that the major Hollywood blockbusters will soon be available in Atmos.

What next for Atmos?

Dolby has also hinted that they're bringing Atmos into mobile headsets to make gaming more immersive and we've been promised a demo of that later in the year, so check back here for that.

We're excited by Atmos. With special effects and movie soundtracks becoming more complex and sophisticated, it stands to reason that the cinema experience has to step up its game as well. And why wouldn't we want to bring that immersive experience into the home?

MORE: Dolby Atmos - What is it? Where can you get it?