Get to know your Dolby Atmos from your DTS:X with our comprehensive next-gen audio guide
If you’ve been looking into buying a new speaker, soundbar or even a new pair of headphones lately, you may have come across the phrase ‘Spatial audio’ and you may well have wondered exactly what it is.
Rather than just a simple new tech buzz phrase, spatial audio is actually a pretty big deal and represents a seismic shift in how you can experience sound; whether that’s music or home cinema soundtracks.
It’s arguably the most significant advancement for audio since the advent of stereo.
Stereo split the one channel audio experience into two, offering us right and left audio signals that worked in harmony.
Spatial audio takes this a whole lot further by transcending the limitations of traditional left-right audio, creating a truly three-dimensional soundscape where audio elements seem to originate from all around you, even from above and behind… and all without you having to run speaker cable all over your living room.
It isn’t just a subtle improvement on surround sound systems that have gained popularity in the past couple of decades; it’s a complete reimagining of audio immersion, which lets you feel completely absorbed into the narrative, the game, or the music.
But is it worth all the hype? And what do you need to do to get some spatial audio into your life?
Read on to find out.
Beyond surround sound
While the idea of immersive sound isn’t entirely new (think of the various iterations of 5.1 and 7.1 surround sound systems that have been available, incredibly, since the 1940s), spatial audio takes a fundamentally different approach.
Traditional surround sound relies on assigning sounds to specific speaker channels. For example, in a 5.1 system, sounds are directed to the left front, center, right front, left surround, right surround, and subwoofer channels.
In a real-world example, you might have a Sonos Beam doing three of the 5.1 count – front, left and center – with two Play:1s at the rear making up five, with a Sub adding the all important point one.
Spatial audio, however, utilizes object-based audio. This means that instead of assigning sounds to fixed speaker locations, each sound – think a character’s voice, a car in the distance, a rumbling explosion – is treated as an independent object that can be precisely positioned and moved within a three-dimensional sonic space.
This is the underlying principle behind leading spatial audio formats like Dolby Atmos, DTS:X, and Sony’s 360 Reality Audio.
These formats allow sound designers to create incredibly realistic and dynamic audio experiences, placing sounds with pinpoint accuracy in the 3D sound-field.
Spatial audio for home cinema
For your home theater setup, spatial audio is primarily experienced through sophisticated soundbars and multi-speaker systems. These systems employ a variety of techniques to create the illusion of sound coming from all directions.
Take that Sonos 5.1 system example we talked about earlier. Swap that Beam out for the likes of a Sonos Arc or a Beam 2, throw some Era 300s at the rear – all of which pack Dolby Atmos smarts – and you’ve suddenly got yourself a 7.1.4 system, which means 7 at ear level now, not 5, plus 4 overhead speakers, and the .1 for the sub remains.
In fact, the latest Sonos Arc Ultra claims to do 9.1.4 sound all on its own.
And that’s without actually having any speakers physically placed above ear level, rather by using speaker drivers positioned at the ear level that fire certain sounds upwards so that they bounce off the ceiling and hit your ear from above.
Upward-firing smarts
These drivers that are designed to bounce sound off the ceiling effectively create a height dimension to the mix.
This allows for realistic reproduction of sounds that sound to the listener like they originate from above – think rain falling, helicopters flying, or even the subtle ambience of a cathedral.
Soundbars like the Sonos Arc, and full systems like the Samsung HW-Q990C, incorporate upward-firing speakers to deliver these height effects.
But it’s not all about creating virtual sounds from above, with Spatial Audio also able to create a wider and more enveloping soundstage using side-firing speakers.
These drivers bounce sound off the side walls of your room, creating the impression of speakers placed further apart than the soundbar itself.
Some soundbars, such as the Arc Ultra, also employ sophisticated digital signal processing to virtualize rear surround speakers.
This technology creates the illusion of sound coming from behind you, even when physical rear speakers are not present.
This is a super useful feature for people who may not have the space, or the wiring, for a ‘real’ surround sound setup.
Tidying up your room
Because of all those sound waves firing and bouncing around, the room you use spatial audio speakers in can also affect its performance.
No two rooms are exactly alike, and factors such as room size, shape, and even your furniture can all affect sound quality.
To compensate for these variations, many high-end soundbars and AV receivers incorporate room calibration software.
Technologies like Sonos Trueplay and Dirac Live use microphones to analyze the acoustics of your room and then automatically adjust the audio output to optimize the sound for your specific environment.
This ensures that you’re getting the best possible listening experience, regardless of the quirks of your room.
Psychoacoustic, addict, insane
In addition to physical speaker placement and room calibration, spatial audio systems often use psychoacoustic processing.
No, this isn’t what John, Paul, George and Ringo did after their visit to the Maharishi in 1968, it’s actually some cutting-edge tech that uses complex algorithms to manipulate how your brain perceives sound directionality.
By subtly altering the timing and phase of audio signals, these systems can create the illusion of sound coming from specific locations, even when the speakers are physically located elsewhere.
It’s some pretty advanced tech that’s particularly effective in creating a sense of spaciousness and immersion, even with a relatively small number of speakers, or indeed just one.
If you’ve stood directly in front of a Dolby Atmos soundbar pumping out the sound from a blockbuster movie, with audio seemingly coming from every direction, with no actual speakers in those places, then you’ve experienced psychoacoustic processing.
Personal spatial audio
Spatial audio on headphones takes a different approach than speaker-based systems.
Since headphones are inherently close to the ears, the focus is on creating a convincing illusion of sound coming from outside the head, which is achieved through a combination of techniques.
Head-tracking technology, as found in headphones the likes of the Sonos Ace or Apple’s AirPods Max, use built-in gyroscopes and accelerometers to track the movements of your head.
The audio dynamically adjusts in real-time as you turn your head, helping to create a more realistic and engaging experience, particularly for movies and VR applications.
For example, if you’re watching a movie and a character speaks from the left side of the screen, the audio will shift as you turn your head, maintaining the illusion that the sound is coming from that fixed location.
Another core component of headphone-based spatial audio is binaural rendering. This technique uses Head-Related Transfer Functions (HRTFs) to simulate how sound naturally travels to your ears in a 3D space.
HRTFs are essentially a set of filters that represent how your head and ears shape sound waves. By applying these filters to audio signals, spatial audio systems can create a convincing sense of depth and directionality, even though the sound is only being delivered through two small drivers.
Dolby Atmos for Headphones, Windows Sonic, and Sony 360 Reality Audio all rely on binaural rendering to create their respective spatial audio experiences.
The battle of the formats
While all three leading spatial audio formats – Dolby Atmos, DTS:X, and Sony 360 Reality Audio – aim to create immersive 3D audio experiences, they do take slightly different approaches.
Dolby Atmos is currently the most widely adopted spatial audio format, supported by a vast range of devices, from soundbars and AV receivers to streaming services and gaming consoles. Its broad compatibility and extensive content library make it the most popular choice for home theater setups and you’ll no doubt have seen the Dolby Atmos slapped on new TVs or AV equipment you’ve seen in the shops.
DTS:X is a strong competitor to Dolby Atmos, offering similar object-based 3D audio capabilities. One of the key advantages of DTS:X is its flexibility in speaker placement. It doesn’t require specific speaker configurations, allowing it to adapt to a wider range of home theater setups.
Sony’s 360 Reality Audio is primarily focused on music. It aims to create a spherical soundscape around the listener, precisely placing individual instruments and vocals in a three-dimensional space. While it can be used for movies and games, its strength lies in its ability to enhance the musical listening experience.
Is spatial audio worth the hype?
For anyone who is passionate about home theater, gaming, or immersive music experiences, spatial audio is a true game-changer… a massively overused phrase in tech – but one that is definitely appropriate here.
It elevates the entertainment experience to a completely new level of immersion, making you feel like you’re truly part of the action.
Whether you choose a Dolby Atmos-enabled soundbar or invest in a full multi-speaker system, the difference in audio quality will be pretty dramatic.
For headphone users, the benefits of spatial audio are more situational. It can significantly enhance movie and gaming experiences, adding a sense of depth and realism that traditional stereo headphones simply can’t match. While spatial audio can also be used for music listening, the impact might not be as pronounced for casual listening, although a lot of music is now being mixed with spatial audio in mind and it’s making a huge difference.
Ultimately, the best spatial audio experience depends on your individual needs, preferences, and budget. However, there’s no denying that spatial audio represents the future of sound, and it’s a future that’s quickly becoming a reality.
