What is Auro-3D Surround Sound?

A lot of people are asking What is Auro-3D surround—particularly in light of the impressive demo held at this year’s 2014 CEDIA Expo in Denver, CO. As it turns out, Auro-3D may feel like the new kid on the block, but they’ve been around for over 8 years. Back in 2006 the Auro 9.1 listening format was launched at the AES Convention in PARIS. At a following series of workshops titled “Surround with Height Channels”, an additional reveal was made in San Francisco.

Then, in October of 2010, Auro Technologies presented the Auro-3D Cinematic Systems (including both Auro 11.1 and 13.1), the Auro Codec, and the Auro creative tools at the AES Spatial Audio Conference in Tokyo. A year later, the first installations of Auro 11.1 started debuting in cinemas. The movie Red Tails was the first film mixed using Auro-3D.

What is Auro-3D Surround Really?

Unlike Dolby Atmos, which is object-oriented, Auro-3D is a PCM-based lossless “channel-based” solution, similar to current Dolby TrueHD or DTS-HD Master Audio. It’s based on the principle that the subconscious mind is highly sensitive to sound origins and character. When we listen, our brain expects a high degree of “auditory coherence” between sounds in order to register them as genuine. We’re not dumb, and so our mind rejects sounds as “inauthentic” when recorded audio doesn’t live up to a level of reality expected by our ears. Auto Technologies asserts that true immersion is only achieved when you are presented with a truly seamless and comprehensive surround field—and that involves a significant emphasis on height channels.

As a result, all Auro-3D listening formats utilize height channel both above and around the listener. Auro-3D claims that this is only possible by using a “Top” Layer. This diagram shows the basic 3-layer principle behind the Auro-3D surround experience:

How Auro-3D Sound is Broken Down by Layers

Auro-3D Top Layer

This top layer is situated directly above the listener. It can be an array of speakers (as in a larger theater) or a single speaker. The top layer serves to enhance the realism of fly-over effects by creating a “bridge” with the second “Height” layer. By using a combination of Top and Height layers, Auro-3D surround can produce an enveloping sphere or “cocoon” of sound around the listener.

Auro-3D Height Layer

The Auro-3D Height layer is positioned approximately 40° above the Lower layer and is the most important layer in the surround “sphere”. The Height layer captures the ambient reflections normally experienced in this layer and allows Auro-3D to produce a more natural sound while improving sound source localization. The Height layer is what will allow you to literally locate a plane specifically as it flies overhead and two the right of the listening position.

Auro-3D Lower Layer

It’s this Lower layer, which occurs between 0° and 20° that produces the important 2D horizontal plane where most ear-level source sounds are located in the mix. All of the dialogue will come from here as will the foundational effects and music that make up the base of a movie soundtrack. While the Height and Top layers fill in the surround “sphere”, the Lower level continues to be the anchor by which everything comes together into  cohesive environment.

Auro-3D Formats and Channel Configurations

Here are the four primary Auro-3D configurations you’ll see, including two designed specifically for home theater and two designed for larger theaters:

This system builds upon a standard 5.1 speaker configuration by adding 4 new speakers atop the existing front and surround speakers. The result is a 9.1 system with height channels overhead to expand the immersive effect.

This system, like the Auro-3D 9.1 configuration, builds upon a standard 5.1 speaker arrangement by adding 4 new speakers atop the existing front and surround speakers. The 10.1 system also adds a singular top speaker in the middle of the room to give a third layer of sound to the environment.

This three-layer cinema surround format features speakers placed above the traditional 5.1 channels, including a center height speaker. There’s also a center-mounted speaker that represents the top height channel for an even deeper immersive effect. Since this is a channel-based system, multiple speaker arrays are also supported via DSP and standard multichannel amplification and processing systems.

This three-layer cinema surround format, like the 11.1 configuration, features speakers placed above the traditional multi-channel speakers, but this time using a 7.1 configuration. There is also, like the Auro-3D 11.1 setup, a center height speaker. There’s also a center-mounted speaker/channel that represents the top height channel for an even deeper immersive effect. Since this is a channel-based system, multiple speaker arrays are also supported via DSP and standard multichannel amplification and processing systems.

3D Over Headphones
Auro-3D also has something called 3D Over Headphones which is specially designed to capture the spatial effect of Auro-3D in a portable, personal listening environment.

Euro Listening Formats

• Backwards compatible with 5.1 standard
• Compatibility between ALL AURO Formats
• Compatibility across all platforms:
• Cinema, Home AV systems, Automotive, Headphones
• Compatible with 22.2

Auro Technical Solutions

• Natural compatibility with PCM
• DCI Compliant (watermarking)
• Uses HDMI Standard (Max 8 channels)
• Easily integrated into existing workflows & equipment
• Just ONE PCM carrier: Single File Distribution

Current/Past Theatrical Releases in Auro-3D 11.1

• John Wick
• The Maze Runner
• The Expendables III
• Teenage Mutant Ninja Turtles
• Into the Storm
• Lucy
• Transformers: Age of Extinction
• How to Train Your Dragon 2
• The Amazing Spiderman 2
• Oculus
• Mr Peabody & Sherman
• I, Frankenstein
• Ender’s Game
• Elysium
• Turbo
• The Croods
• Oz the Great and Powerful
• Rise of the Guardians
• Red Tails (the first movie to be mixed in Auro-3D)

Upcoming Auro-3D Films

• The Hunger Games: Mockingjay – Part 1 (21 November 2014)
• Black & White: The Dawn of Justice (October 2014)
• The Penguins of Madagascar (26 November 2014)
• Freedom (release date TBA)
• B.O.O.: Bureau of Otherwordly Operations (5 June 2015)
• Kung Fu Panda 3 (23 December 2015)
• How to Train Your Dragon 3 (17 June 2016)
• Trolls (4 November 2016)