Home cinema isn't just about the picture, sound is just as important. For years we've had 5.1 and 7.1 surround sound systems, but now that's all changed thanks to the mainstream arrival of Dolby Atmos.

Dolby Atmos has made a big impact since its arrival in cinemas and homes, doing for sound what Blu-ray and 4K Ultra HD did for the visuals.

But what is Dolby Atmos? And why does it get audiophiles and cinephiles excited?

What is Dolby Atmos?

Dolby Atmos takes the longstanding 5.1 surround sound but adds extra height channels to provide a more enveloping sound effect in your room. Rather than have sounds of raindrops, or a helicopter moving around the same height as your ears with 5.1 for example, with Atmos you'll be able to hear rain falling from above or a helicopter moving from over your head and over into the distance. At least, that's the theory.

It introduces new speaker configurations, such as 5.1.4, where there are five speakers around the room, one subwoofer and four height channel speakers. You could also have 5.1.2, 7.1.2 or 7.1.4. If you want some extra low-end grunt, you can also add an extra subwoofer into the mix.

Dolby Atmos isn't defined by the number of channels, per se, but by the enhanced ability to deliver this more immersive sound experience. That's a line that's being used more and more by Dolby and supporting brands as a wider range of Dolby Atmos enabled devices become available.

What do I need to get Dolby Atmos?

For the best possible Atmos experience, in-ceiling speakers are the way to go.

But not everyone is able to facilitate them, so the more common approach at home is to get upward firing Atmos speakers to fire the sound up to the ceiling and reflect back down to the listening position.

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For those with a traditional separates setup, this might just mean the addition of these upfiring modules. Onkyo, for example, has the SKH-410 speakers that you place on top of your existing left and right floorstanders, or nearby on an AV stand. These are dedicated to Dolby Atmos and are angled slightly to bounce the sound off the ceiling and back down to your sitting position.

In order to drive those speakers, whether they're upward firing modules or built-in to the ceiling, you'll need a compatible AV receiver. The majority of major AV brands have now added Atmos support the bulk of their ranges, and all at different price points to suit different budgets.

But that's not the only route to getting Dolby Atmos in your home.

What Dolby Atmos soundbars are available?

We've been talking as if we're assuming you have space for a full Atmos surround sound setup. What if you want the added height effect but space is at a premium? Then you can go for a Dolby Atmos soundbar.

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Most of the big audio brand now offer a Dolby Atmos soundbar in some form. Many offer models with upfiring speakers built into the top of the body, some offer a virtualised Atmos effect, recreating a wider sound stage to bring that immersion. 

A few years back it was only the high-end bars that had this option, but more and more we're seeing mid-range bars offering Atmos too, meaning it's getting cheaper and cheaper to get that boosted audio effect.

What other hardware do I need for Dolby Atmos?

A big part of the puzzle, of course, is the source. You need to find a way to feed that Dolby Atmos signal to your speakers. The starting point for movie fans is likely to be a Blu-ray player. As long as the Blu-ray player has been set to output a direct bitstream signal, your Dolby Atmos-enabled receiver or soundbar should be able to decode the signal and send the height channels to the Dolby Atmos speakers.

You will of course also have to make sure the Blu-ray disc you're watching has a Dolby Atmos soundtrack on it. You can check the rear of the case to see if it does.

Some TV services offer Dolby Atmos - BT Sport Ultimate for example, if you have the 4K Ultra HD set-top box, will give you Atmos on some live football matches.

Media streaming is another area that promises to supply Dolby Atmos soundtracks, with services like Apple TV and Roku offering support for Dolby Atmos - although again, you'll need to connect those devices to a receiver of some sort that will support Dolby Atmos.

You can use a games console too, as the PlayStation 4, Xbox One and Xbox One S all support Atmos soundtracks on films, with some games beginning to adopt the format.

There are also TVs that now support Dolby Atmos. LG has, for a couple of years, claimed to offer Atmos sound from its TVs' speakers, for example. This isn't like the experience you'd get from a full setup - so Atmos needs to be approached with caution, as not all Atmos experiences are the same.

Importantly you need to ensure you have an Atmos source (streaming service, Blu-ray), something to handle the signal (a receiver) and the speakers to finally give you the sound.

What content can I watch in Dolby Atmos?

As with any new format, when it first launched, there wasn't a lot of Dolby Atmos content around. One of the first movies to be released with an Atmos soundtrack was Transformers: Age of Extinction. Luckily films with Atmos have progressed since then, in both quality and quantity. Many Blu-rays on the shelves will have an Atmos soundtrack - so check your collection.

BT TV has added Atmos to its 4K Ultra HD sports channel. Live sports will be shown with the added height from 2017, but to get it you'll need to have the BT YouView+ 4K Ultra HD set-top box.

Sky has added Dolby Atmos to its content offerings. Atmos has been added to the Sky Sports Premier League channel, meaning all 124 games shown will have the added height channels, resulting in a more immersive experience when you're watching at home.

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Netflix also offers Atmos content, but only through Xbox One, Windows 10 or LG OLED TVs (2017 onwards).

More recently, Apple has confirmed that it's adding Dolby Atmos to Apple TV 4K. The good thing about the Apple TV offering is that it's one of the few providers that will give you Dolby Vision and Dolby Atmos on a wide range of titles. If you own any of those titles already, Apple will also upgrade you for free. 

What about Dolby Atmos on laptops, phones and tablets?

In recent years we've seen Dolby Atmos being talked about in new terms - not just in the context of the home cinema experience. 

Remember above when we said that Dolby was talking about Atmos not in terms of the number of speakers, but with the aim of delivering the best audio experience possible? That mantra has now flowed through into devices like laptops, tablets and phones. We're seeing an increasing number of devices claiming to offer "Dolby Atmos" audio. 

In reality (and this is slightly confusing), the Atmos branding in this context isn't about decoding those channels and using a wider range of speakers - it's about virtualising a more immersive soundscape. Yes, those devices sound better when the Dolby Atmos mode is turned on, but it's not aiming to place sound objects in space like you might get at home from your separates system. 

So, take other forms of Dolby Atmos (on mobile devices) with a pinch of salt - it's using the same branding, but it's not really the same thing.