Spatial Audio: Meaning, Facts & More

Spatial audio refers to sound that gives listeners a sense of space and dimensionality beyond standard stereo audio. As defined by PCMag, spatial audio is “Audio amplification and speaker technologies that reproduce the spaciousness of sound in either a real venue such as a live concert or in a fabricated three-dimensional space” (https://www.pcmag.com/encyclopedia/term/spatial-audio).

Spatial audio works by using advanced audio processing to manipulate sound in a way that mimics how humans hear sound in the real world. Sound characteristics like volume, frequency, and timing are adjusted to give the illusion that sounds are coming from different directions and distances (https://www.interaction-design.org/literature/topics/spatial-audio). This creates an immersive, multi-dimensional audio experience.

Some key applications of spatial audio include virtual reality, augmented reality, movies, music, headphones, home theater systems, live events, and more. Spatial audio adds realism, envelopment, and a heightened sense of space to all of these experiences. It allows creators to fully transport listeners into their imagined worlds.

How Spatial Audio Works

Spatial audio aims to recreate a 3D soundscape and provide an immersive listening experience by simulating how sounds reach a listener’s ears in the real world. It achieves this using a few key techniques:

First, spatial audio relies on head-related transfer functions (HRTFs). HRTFs are filters that simulate how sound waves are modified by the shape of a listener’s head, ears, and torso before reaching the eardrums. By applying different HRTFs to sounds based on their intended position, spatial audio can make it seem like sounds are coming from specific directions rather than just the stereo left/right.

HRTF processing enables binaural rendering, which is a key part of spatial audio. Binaural rendering aims to replicate the subtle differences in timing, loudness and timbre that the listener would experience naturally as sounds arrive at their two ears from various directions. This creates a convincing sense of space and immersion.

Another key distinction is between channel-based and object-based spatial audio. Channel-based formats like 5.1 surround sound encode audio to fixed speaker channels. Object-based formats like Dolby Atmos encode audio as distinct objects that can be positioned freely and rendered to the speaker setup dynamically. Object-based audio gives more flexibility and accuracy in simulating 3D space.

By combining advanced HRTF modeling, binaural rendering, and object-based audio, spatial audio technologies can deliver immersive 3D sound over headphones and speakers.

Spatial Audio Formats

There are several major formats for spatial audio currently in use:

Dolby Atmos

Dolby Atmos was introduced in 2012 and has become one of the most widely adopted spatial audio formats. It creates immersive audio by allowing sounds to be placed and moved in a three-dimensional space. Atmos achieves this through object-based audio, where sounds are rendered dynamically based on metadata rather than specific channels (https://zenodo.org/record/1188325/files/PhD_Research_Proposal_definitive.pdf?download=1).

DTS:X

DTS:X is Dolby Atmos’ main competitor, using similar object-based audio techniques. It was also introduced in 2012. A key difference is DTS:X supports up to 32 audio objects, compared to 118 for Dolby Atmos. However, DTS:X has greater backward compatibility with existing DTS formats (https://zenodo.org/record/1188325/files/PhD_Research_Proposal_definitive.pdf?download=1).

Sony 360 Reality Audio

360 Reality Audio was launched by Sony in 2019. It focuses on delivering immersive music experiences. Sony’s format uses object-based spatial audio along with personalized HRTFs generated from photos of the listener’s ears. This aims to deliver optimized spatial audio tailored to each individual.

MPEG-H

MPEG-H Audio is an object-based spatial audio standard developed by the Moving Picture Experts Group. Introduced in 2013, MPEG-H supports interactive and personalized audio along with high adaptability across different playback systems (https://zenodo.org/record/1188325/files/PhD_Research_Proposal_definitive.pdf?download=1). However, adoption has been limited compared to Dolby Atmos and DTS:X.

Spatial Audio for Music

Spatial audio has become increasingly popular for music listening. Major streaming services like Apple Music and Tidal now offer spatial audio tracks in formats like Dolby Atmos. This allows listeners to experience music with immersive, multi-dimensional sound through supported devices like AirPods.

Classical music recordings have also utilized spatial audio to recreate the experience of listening in a concert hall. Microphones are placed throughout the performance space to capture the venue’s natural reverberation and room acoustics. When played back over a spatial audio system, listeners feel transported into the recording location.

For live concerts and events, spatial audio can make audiences feel like they have the best seat in the house. Specialized microphone setups and mixing allow every detail and nuance of the live sound to be preserved and distributed spatially. This creates an immersive experience for audience members, even if they are seated far from the stage.

Spatial Audio in Home Entertainment

Home entertainment systems like soundbars, home theaters, headphones, and surround sound speakers are increasingly adopting spatial audio technologies to create more immersive audio experiences. Key formats like Dolby Atmos and DTS:X have been incorporated into many new home audio products.

Soundbars and home theater systems from brands like Sonos, LG, Samsung, Sony, and others now support Dolby Atmos for height and surround channel information. This allows audio to sound like it’s coming from all around you, even above you, as opposed to just straight ahead from the TV speaker. Many Blu-ray discs and streaming services now offer Dolby Atmos mixes of movies and TV shows to take advantage of this immersive spatial audio in home theaters.

Spatial audio is also coming to headphones from brands like Apple, Sony, and others. Apple’s AirPods Pro and AirPods Max use head-tracking technology to create a surround effect, making audio feel like it’s coming from all directions. Sony’s 360 Reality Audio format similarly spatializes music for headphones with 3D effects.

For full surround home audio, AV receivers, speakers, and systems from brands like Denon, Yamaha, and Pioneer allow setting up multi-speaker arrangements with height channels to play back object-based spatial audio formats. This creates highly immersive surround sound at home. As spatial audio continues advancing, adoption in home entertainment is expected to grow substantially in coming years.

(Sources: https://www.apple.com/newsroom/2021/06/apple-musics-zane-lowe-explains-how-spatial-audio-will-transform-music/, https://www.killerstartups.com/apple-incentivizes-spatial-audio-adoption/)

Spatial Audio for Gaming

Spatial audio has become a popular feature in modern gaming, particularly with the PlayStation 5 and Xbox Series X/S consoles that support it. These new consoles have dedicated hardware to enable immersive spatial audio in compatible games.

Sony’s PlayStation 5 includes a Tempest 3D audio engine that can simulate surround sound and positional audio when using stereo headphones [1]. Games like Returnal, Ratchet & Clank: Rift Apart, and Spider-Man: Miles Morales take advantage of spatial audio on PS5 for a more immersive experience.

The Xbox Series X and S also support spatial sound through Dolby Atmos and DTS:X technologies. Games that use spatial audio on Xbox include Gears 5, Forza Horizon 5, and Halo Infinite. Microsoft also offers Windows Sonic, Dolby Atmos for Headphones, and DTS Headphone:X support on Xbox and Windows 10 PCs.

Spatial audio aims to give players improved directionality and depth in game audio, allowing them to better pinpoint enemies, effects, and other audio cues by simulating surround sound over stereo headsets. This creates a more engrossing and realistic setting that fully immerses players in the game world.

Spatial Audio For VR/AR

One of the most exciting applications of spatial audio technology is in virtual reality (VR) and augmented reality (AR) experiences. By using head-tracking and room modeling, spatial audio can create incredibly immersive 3D soundscapes that enhance VR/AR apps and games.

The Oculus headsets have been at the forefront of implementing spatial audio in their VR devices. The built-in headphones on Oculus Quest and Oculus Rift generate positional 3D audio that makes you feel like sound is coming from all around you. This makes the virtual environments feel much more real and enhances the sense of presence.

Spatial audio adds crucial depth and realism to VR apps like Beat Saber where you can hear the music directionally as you slash through cubes with the controllers. It takes social VR apps like VRChat to the next level by letting you actually hear people’s voices coming from the location of their avatars.

As VR technology improves, spatial audio will play an integral role in making those virtual worlds feel authentic. The combination of 3D visuals and 3D sound can trick your brain into feeling fully immersed in amazing VR experiences.

Spatial Audio Production

Spatial audio introduces new techniques and considerations for audio production compared to traditional stereo. When recording for spatial audio, it’s important to capture a 3D soundscape with audio coming from all directions. This may require using omnidirectional microphones or microphone arrays to pick up a full 360 degree perspective (dearVR SPATIAL CONNECT BUNDLE by Dear Reality).

The mixing process also changes significantly. With spatial audio, the mixer can position individual audio elements at exact locations in a 3D space. This provides greater realism and immersion than just left/right panning. However, it also adds complexity. Mixers need tools like the Dolby Atmos integration in PreSonus Studio One 6.5 to mix in a 3D environment while monitoring the results through headphones or speaker setups (PreSonus Studio One Update Adds Dolby Atmos Tools).

There are challenges transitioning production workflows to spatial audio. It requires new equipment, software, and most importantly, new mixing techniques. But the result is a more enveloping experience for listeners. Overall, spatial audio has opened up new creative possibilities for producers and sound designers (Spatial Audio Production Workflow Tutorial – YouTube).

Criticisms and Challenges

While spatial audio offers exciting potential, the technology still faces some criticisms and challenges:

Hardware complexity – Producing convincing spatial audio requires complex processing and multiple speakers or headphone drivers. This makes it difficult to implement in many consumer devices.

Inconsistent support across devices – With no universal standard yet, spatial audio capabilities vary widely across different platforms. Features enabled on one device may not work when using another brand or model.

Questionable benefits for some content – While spatial audio can greatly enhance immersive experiences like games and movies, some critics argue its benefits are negligible for music or simpler audio content. The extra production effort may not always be worthwhile.

As cited on XDA Developers, Microsoft Teams’ recent spatial audio feature has significant hardware limitations. And as one Amazon reviewer noted, even the Fire TV Cube has inconsistent spatial audio support.

<h2>The Future of Spatial Audio</h2>

The spatial audio market is predicted to see rapid growth and adoption in the coming years. According to Fortune Business Insights, the global 3D audio market size is projected to reach $12.97 billion by 2026, reflecting a CAGR of 16.9% from 2018-2026. FactMR predicts the global 3D audio market will expand at a CAGR of 16% to reach $32 billion by 2033. There are several factors driving predictions of strong growth and adoption of spatial audio technology.

Firstly, spatial audio is seeing increased use in emerging technologies like augmented reality (AR), virtual reality (VR), and extended reality (XR). Spatial audio can create more immersive experiences in these environments. As AR/VR/XR technologies continue advancing, the demand for spatial audio solutions will also grow. Spatial audio also has applications in navigation, sonification, accessibility features, and other areas that have yet to be fully explored.

Additionally, major companies like Apple, Sony, and Microsoft are investing heavily in spatial audio innovation. Apple Music’s adoption of Dolby Atmos spatial audio has expanded the reach. Ongoing R&D from major players will likely uncover new use cases and drive down costs of spatial audio production and consumption.

Finally, spatial audio is becoming more accessible to content creators. Emerging tools like dearVR and Facebook 360 spatial workstation enable more creators to mix and publish spatial audio. As production becomes more democratized, the amount of spatial audio content will dramatically increase.

In summary, experts predict rapid growth for spatial audio based on expansion into new use cases, heavy investment from tech giants, and easier production tools for creators. The future looks bright for this immersive audio technology.