Dolby Atmos vs DTS:X: The leading object-based audio formats, explained

If you’ve watched a film on a streaming service, bought a 4K Blu-ray or listened to a new spatial audio mix of your favourite album, you’ve probably heard of Dolby Atmos and DTS:X.

These new audio formats are everywhere, promising to revolutionise your sonic experience by immersing you in sound. But what are they, how do they work and where can you find them? Does your soundbar support DTX:S surround sound, for example?

Welcome to the wonderful world of object-based audio.

Dolby Atmos vs DTS:X: A quick history lesson

Before going into detail on Dolby Atmos and DTS:X, it’s worth placing both formats in their historical context.

Sound has been synchronised with film since Al Jolson shouted out “You ain’t heard nothin’ yet!” in The Jazz Singer back in 1927. In those pioneering days film audio was restricted to mono, which meant there was a single channel into which the dialogue, music and effects were all mixed. There may have been more than one speaker behind the screen but those were just to spread out the soundstage, with all of them playing the same mono soundtrack.

Over the following decades, there were numerous attempts to add more channels to cinema sound, starting with Walt Disney’s Fantasound in the late thirties. While this format ultimately failed it was the first to offer genuine stereo or two-channel audio.

With the rising popularity of TV in the 1950s, the Hollywood studios tried to entice cinema-goers back with spectacle by introducing 70mm presentations that offered up to six channels of magnetic sound – five channels behind the wider screen and the sixth as a surround channel.

However, these multi-channel sonic experiences were reserved for high-end cinemas, and even by the 1970s, your average flea-pit was still using mono. Star Wars changed all that, popularising four-channel surround with its Academy Award-winning Dolby Stereo soundtrack. This system cleverly encoded four channels (left, centre, right and surround) into an existing stereo mix, and revolutionised how sound was delivered in the cinema.

The 1990s saw the advent of digital audio with five discrete channels – front left, centre and right, along with rear left and right surround channels. Dolby Digital was first out of the blocks with Batman Returns in 1992, before newcomer DTS roared onto our screens with the release of Jurassic Park in 1993.

Since then there have been a few minor tweaks such as Dolby Digital EX, which was launched in 1999 with the release of The Phantom Menace. This format added an extra rear surround channel using the same matrixing technology originally developed for Dolby Stereo in the 1970s.

By the noughties, both Dolby and DTS were offering digital cinema sound that delivered up to seven discrete channels, along with a dedicated LFE channel for the low-frequency effects (bass). But despite their inherent sophistication these formats still shared something in common with The Jazz Singer’s original mono soundtrack – all of them are channel-based. After nearly a century it was finally time for film audio to get an entirely new objective.

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Dolby Atmos vs DTS:X: What is object-based audio?

The traditional approach to cinematic sound design has been based around channels since its inception, with a centre channel for dialogue, left and right channels for the music and rear channels for the surround effects. While this is an oversimplification, you get the general idea.

Object-based audio takes an entirely different approach, by moving away from a reliance on channels and instead steering audio objects or sound effects around in three-dimensional space to create a sonic experience that’s more immersive and realistic.

To fully achieve this effect, object-based audio formats employ considerably more speakers than earlier sound systems, with speakers above the listener as well as at ear level. This creates a hemisphere of sound within which the audio objects are moved around.

The more speakers at a processor’s disposal the smoother the movement of the sound effects, and the more immersive and realistic this sonic bubble. The beauty of these spatial audio formats is that they map the audio to however many speakers are available – thus retaining as much immersion as possible.

By way of contrast, conventional multi-channel soundtracks allocate all the source audio tracks to a fixed number of channels during mixing. This forces the sound designer to make assumptions about the playback environment that may not apply to a particular cinema.

The addition of audio objects not only allows the sound designer to be more creative but also gives them confidence that the delivery of their carefully constructed mix will be closer to the original artistic intent, regardless of how a particular cinema is set up.

Dolby Atmos vs DTS:X: What is Dolby Atmos?

Dolby has been synonymous with cinema sound for over fifty years, and Dolby Atmos is the company’s object-based audio format, which was first introduced into cinemas in 2012 with the release of Pixar’s Brave.

The technology allows for the storage and distribution of 128 audio tracks, each of which has metadata describing sound properties such as its volume and position in three-dimensional space. The audio mix is also specifically rendered for a cinema’s setup based on the number of speakers available, with each audio track either assigned to a specific channel or as an object.

Dolby Atmos soundtracks for cinemas use a 7.1.2-channel “bed” with seven ear-level channels, an LFE channel and two overhead channels. These handle dialogue, music and ambience, which leaves 118 tracks for objects. The result is an incredible sonic delivery that moves audio objects around seamlessly within a dome of sound, creating a more lifelike aural experience.

Dolby Atmos was launched as a consumer format with the Blu-ray release of Transformers: Age of Extinction in 2014.

In the home, Dolby uses a spatially coded sub-stream to embed Atmos into a lossless Dolby TrueHD or lossy Dolby Digital Plus soundtrack. This makes the format backwards compatible, allowing those without the necessary decoding to still enjoy 5.1- or 7.1-channel sound, but also ensures the sub-stream is an efficient representation of the full cinema mix for those with Dolby Atmos-compatible equipment.

The consumer version of Dolby Atmos can support up to 35 channels, with the simplest setup being based around a 5.1.2-channel speaker configuration such as the Hisense AX5125H, which spreads those channels across a soundbar, subwoofer and pair of rear speakers.

The most complex Atmos arrangement uses a full 24.1.10-channel layout. However, due to spatial coding, domestic Atmos is delivered with a maximum of 16 concurrent elements that adapt to the content dynamically. This reduces the total active objects from the original 128 down to 32, with a 7.1.4-channel bed and up to 20 additional dynamic audio objects.

When you consider the difference in size between a lounge or even a dedicated home theatre and a commercial cinema that’s more than sufficient to deliver a fully immersive experience without compromising the sound designer’s original artistic intent. Something like the Samsung HW-Q990D soundbar can put its 11.1.4-channel arrangement to work to reproduce Atmos soundtracks incredibly well.

Dolby Atmos vs DTS:X: What is DTS:X?

DTS, or Digital Theatre Systems to give the company its full name, has been used in cinemas since its launch in 1993. DTS:X is the name of its spatial sound format, which is a rival to Dolby Atmos and also uses object-based audio.

The introduction of DTS:X was essentially the opposite of Dolby Atmos, with the former being launched in early 2015 as a consumer format before being offered to commercial cinemas later. The first Blu-ray to include a DTS:X soundtrack was Ex Machina, and since then the format has been included on a large number of Blu-rays and 4K discs. The format is delivered using lossless DTS-HD Master Audio, making it backwards compatible and allowing those without the necessary decoding to still enjoy 5.1- or 7.1-channel sound.

As an object-based audio format, DTS:X offers increased immersion using an expanded array of speakers to produce a three-dimensional soundstage. The format is based on DTS’s Multi-Dimensional Audio (MDA) platform, which the company has made open and license-free to expand the popularity of DTS:X.

The initial version was restricted to 11.1 channels, but the introduction of DTS:X Pro has expanded the total speaker layout to a maximum of 30.2 channels with added width and overhead options – putting DTS:X on an equal footing with Dolby Atmos.

Of course, you don’t need to buy thirty speakers and two subwoofers to enjoy DTS:X, and the strength of the format is its flexibility. It doesn’t require a specific speaker layout, adapting its processing to whatever is available. This allows you to arrange your speakers how you want, while still enjoying the benefits of immersive audio. But it also means your system can evolve as you add more speakers over time, expanding the channel configuration. LG’s US95TR is one of our favourite soundbars to support DTS:X through its 9.1.5-channel setup. It supports Atmos too, making it a great pick if you want to be able to access both object-based formats.

Dolby Atmos vs DTS:X: How do they differ?

Since both formats are object-based they’re quite similar, with the same maximum number of channels. Dolby Atmos has an edge in terms of total objects being rendered at any one time, and DTS:X has a slight advantage when it comes to bass management. In addition, your soundbar, AV processor or AV receiver will be using the same speaker layout for both formats, so it is doubtful one would sound any different to the other.

DTS claims that DTS:X is the more flexible format because it will work with “any speaker configuration within a hemispherical layout”. However, common sense dictates that you can’t have sounds emanating from where there isn’t a speaker, so these claims of full immersion regardless of the speaker configuration should be taken with a pinch of salt.

The only way such claims are possible is through the use of psychoacoustic processing, which tricks the brain into thinking a sound is emanating from a specific location. Both companies are guilty of making rather spurious claims of full immersion from minimal setups, with two-channel TVs claiming to support Dolby Atmos. In reality, if you want to get the full benefit of Dolby Atmos or DTS:X you’re going to need a lot more speakers than two.

Dolby Atmos vs DTS:X: How can you get the most from these formats?

Despite claims that DTS:X works with any speaker configuration, if you want to get the most out of it or Dolby Atmos you need at least two height channels. Without them, there’s no realistic way to create that all-important hemisphere of sound through which objects can be moved.

The good news is that you don’t necessarily need to install speakers on your ceiling to create these height channels, with soundbars and even speaker manufacturers using up-firing drivers to bounce sounds off the ceiling, thus creating the illusion of an overhead channel.

While this solution is convenient, it isn’t perfect. For one thing, you can’t bounce low frequencies, so height channels produced using up-firing drivers will lack any bass. The other problem is that their effectiveness is very dependent on your ceiling. The lower, flatter and more reflective it is, the better the effect. If you have a very high or vaulted ceiling, this approach isn’t going to work.

If you’re building a dedicated home cinema, you owe it to yourself to install in-ceiling speakers and get the best possible experience from Dolby Atmos or DTS:X. You don’t need to go mad when it comes to the overhead channels, but the more speakers your system has to play with, the more realistic the hemisphere of sound and smoother the steering of the objects.

In reality, most people will be restricted in terms of the number of speakers they can install – either due to budget, space or limited processing or amplification in their AV receiver. This raises an interesting question, if you’re limited to nine channels do you go for a 5.1.4- or 7.1.2-channel speaker configuration?

My advice would be to choose the 7.1.2-channel layout because the two overhead channels will be sufficient to create height effects but without the two rear speakers, there will be a big sonic hole behind you. If you imagine immersive audio as a bubble that envelops you, the use of seven speakers to encircle the main listening position plus two overhead is more effective at creating that bubble than only five at the front sides, plus, it’s unlikely you’ll notice the four overhead. One such option is the Philips Fidelio FB1. This bolsters a 5.1.2-channel speaker setup by adding two virtual front channels and supports both Atmos and DTS:X.

Dolby Atmos vs DTS:X: Where can you find them?

This is where the two formats differ significantly, with Dolby Atmos bordering on the ubiquitous, whereas DTS:X soundtracks are becoming harder to find.

At the cinema, Dolby Atmos dominates, with almost all new releases using the format for their soundtracks. Not all cinemas offer Dolby Atmos, but you can bet any new movie already has a Dolby Atmos mix ready to go.

The pre-eminence of Dolby Atmos extends to the domestic market as well, where all the streamers use Dolby Digital Plus to deliver Dolby Atmos where it’s available. Most of the big shows from the likes of Netflix, Amazon and Apple use Dolby Atmos, and almost no one is currently using DTS:X.

As a result, you’ll find there are countless Atmos-enabled TVs and soundbars available at a huge range of price points. You can pick up something like the Creative Stage 360 soundbar for under £200, though bear in mind that this is limited to 2.1 channels, so its Atmos impact is very constrained. Even affordable TVs like the Samsung Q60D support Atmos, though again, there’s only so much a television with two down-firing speakers can achieve with object-based audio. For a more convincing Atmos built into your TV, you’d need to go for something like the Panasonic Z95A, which incorporates a speaker bar underneath its panel and also crams in side- and up-firing speakers.

The situation isn’t quite so one-sided when it comes to Blu-ray and 4K discs, but note, the number of releases with Dolby Atmos far exceeds those with DTS:X soundtracks. In addition, many older films are being remixed in Dolby Atmos for their release on 4K disc, and while this has also been done occasionally for DTS:X, that number has trailed off in recent years.

There has been a recent trend to remix classic albums in Dolby Atmos, with music streamers like Tidal and Apple offering these new mixes, and some of them also being released on Blu-ray. And once again it’s another area where Dolby Atmos has become the dominant sound format.

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Dolby Atmos vs DTS: X: What is upmixing?

If you’ve gone to the trouble of putting speakers everywhere, including on the ceiling, you want to get the maximum benefit for your effort. While most new movies and streaming shows have Dolby Atmos soundtracks, many older movies will likely still be restricted to 5.1 channels at best.

This is where upmixing comes in handy, taking non-immersive soundtracks and remapping them to use all the available speakers. Dolby offers Dolby Surround and DTS provides DTS Neural:X, with both surprisingly effective at creating an immersive experience despite the fact the original audio was never encoded for it.

While you can use Dolby Surround to upmix DTS soundtracks and vice versa, I generally feel it makes logical sense to use Dolby Surround with Dolby soundtracks and DTS Neural:X with DTS soundtracks. If the audio is encoded in PCM then it’s entirely up to you, and both upmixers are equally effective.

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Dolby Atmos vs DTS:X: What is IMAX Enhanced?

DTS has formed a partnership with IMAX to create what they call IMAX Enhanced titles. These releases have pictures that are mastered using IMAX’s post-production process, along with an optimised DTS:X soundtrack to deliver the full IMAX audio experience.

After an initial flurry of IMAX Enhanced 4K Blu-rays, they seem to have completely dried up in recent years; though as you’ll see, IMAX Enhanced is offered by several streaming services such as Disney+, Sony Pictures Core and Rakuten TV. These are currently the only places where you can stream DTS:X audio, and even these services primarily use Dolby Atmos.