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All Mixed Up, Part 2

All Mixed Up, Part 2
by Gary Woods

As I said last week everybody was happy with 5.1 cinema sound using a Left-Center-Right speaker configuration with 2 Surrounds and a Sub-woofer up until about 2012 when along came what has been dubbed “Immersive Sound.” The first company that came out of the box with “Immersive Sound” was Auro Technologies in association with Barco Cinema and their system is called Auro 3D. It first appeared in a pictured called “Red Tails” and was released in Auro 11.1, which was displayed in a staggering 2 theatres.

The Auro 3-D 11.1 basic configuration starts with the standard 5.1 system then has what they call a 5.0 top layer which has a center-ceiling “Voice of God” channel plus four other ceiling mounted speakers. For display in non-Auro 3-D equipped theatres the prints were shipped with either a 5.1 or 7.1 configurations with the additional height and top channels decoded in the individual venues that had the required equipment.

But, if there was one new company with immersive sound on the playing field you knew there had to be a second one not far behind and the second iteration came from Dolby Laboratories. Dolby introduced the Atmos format for the Pixar animated film Brave that debuted on 14 screens.

Dolby had been working with a “Voice of God” speaker since 2002 when it premiered with “We Were Soldiers” but in the meantime they had been experimenting with setting a standard for surround speaker spacing, locations and dispersions as well as mounting angles.  The 2 extra surround channels they added were closer to the screen to fill up the first third of the auditorium with audio where surrounds previously hadn’t resided.   The final configuration with Dolby’s Atmos allows for up to 64 speakers with 2 overhead arrays running the length of the theatre. 

Okay, now we have two different formats, so what’s the difference? Auro-3D currently is channel-based in the classic stereo film manner with recorded tracks assigned to either specific speakers or to an array of speakers. Atmos on the other hand is Object Based Audio (OBA) which means that sounds are not necessarily dedicated to a specific channel or speaker but instead audio files are placed in the three dimensional space of the theatre via metadata containing level and location coordinates. To elaborate on the three-dimensional terminology the audio exists in an XYZ configuration with X being left to right, Y being front to back and Z being height.

So, where did this Z parameter come from? It came from video games of course! The cool thing about Object Based Audio is that it gives us the ability to place sound accurately in multiple theatre configurations. For instances, if we want the sound to come from two thirds of the way up the left wall with OBA it doesn’t matter whether the theatre has 4 speakers on a wall or 8. The position is all that’s important not if it’s coming from speaker 3 or 5.

Next week we’ll talk about scalability, which is how we make this all work with big theatres and small ones like your home.

If you have any suggestions or questions for me please drop me a note at or see my column on the Internet at or call me at (805) 729-0910

Gary Woods is the Computer Trainer for the Santa Barbara Association of Realtors and he is a Broker/Associate at Sotheby’s International Realty.