How They Did It: Bringing 3D Audio to Life
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How They Did It: Bringing 3D Audio to Life

CEDIA
Sep 26, 2014

This three-year home theater project helped write the book on consumer applications for Auros-3D – literally. With a client who was willing to push the envelope and a blank slate of a room to work with, Hometronics pulled out all the stops and designed this one-of-a-kind home screening room.

Their work earned them the Level V Gold Technical Design award for Home Theater as well as the Best Overall Home Theater award in the 2014 CEDIA Electronic Lifestyles® Awards competition.


2014 HT Level 5 Gold


Client’s Needs:


Engaged at the planning stage for this home, Hometronics was presented with a blank slate. A needs assessment determined the room size, which was then drawn in into the house plans. The equipment and technology were given precedence over the room’s interior design.

The client wanted a four-row theater with a wall-to-wall screen that could be sized at his discretion to maintain preferred viewing angles from any row. In addition to viewing HD content, the client wanted the ability to watch multiple sporting events simultaneously and connect to four Xbox consoles so he and his sons could enjoy a larger-than-life, multi-user gaming experience. A 4K projector was chosen in part because it would display four 1080p images simultaneously.

An enveloping audio experience that sounded great at any location was an important feature. Early in construction when immersive audio formats were announced at Cinemacon 2012, Hometronics suggested planning for a future consumer 3D audio format though none had been announced yet, and the client agreed. The new goal was to complete the first residential Auro-3D system in the country.


2014 HT Level 5 Gold


Technical Highlights:


The theater, acoustics, and interiors were all modified to meet the engineering criteria for Auro-3D, which added 17 additional speakers to the theater. Thirty loudspeakers, 14 subs, and 55 amplifier channels were optimized for this 15.1 audio system. Symetrix DSPs are used for crossovers, time delays, phase, and bass balancing for all speakers and subs.

Left/right mains are tri-amped, center and main surrounds are bi-amped, and all Auro speakers are single channel. An acoustically transparent screen and masking materials were used to allow delivery of unimpeded audio from the designated speaker locations regardless of masking position.

The length of the room required an array of side speakers to properly deliver audio consistently to all four rows of seating. The four CAT 22” LFE subs below the screen were encased in 6” of concrete to eliminate all cabinet resonance. Ten subs were placed in specific locations around the theater for bass canceling, producing pure delivery, impact, and then removal of the bass energy, resulting in tight response and a non-fatiguing listening experience.

Audio was enhanced by placing all speakers in an interior acoustical wall, producing the same depth of field achieved with free-standing speakers. The boundary wall, two feet away, was constructed with standard isolation techniques to lower the noise floor. The HVAC system was isolated to eliminate mechanical vibration, and a ridged plenum system routes large-volume, low-velocity air to slot registers producing a quiet HVAC system. Sound absorption panels were used in the projection box to mitigate fan noise.

The system has presets to correlate video sources, masking, and light levels. Projector lamp power increases or decreases automatically based upon room brightness to maintain a reference image. The projector is powerful enough to have a very bright room with full room lighting. The multi-view processor allows up to eight sources to be tiled simultaneously on screen, creating a Vegas sports book feel. The most commonly used sources are multiple satellites for sports and Xbox One consoles. The native 4K resolution of the projector allows four unscaled 1080p sources to be displayed at once.




A Dolby 3D cinema system is integrated within the projector, producing a realistic, high-frame-rate image viewed with passive 3D glasses. Custom Savant modules were written so the user can easily select, control, and direct multi-view sources to the screen in any desired aspect ratio or screen size to fit desired viewing angles. The late inclusion of the Prima Cinema System transforms this theater into a true private screening room.

A 25kVA isolation transformer provides clean technical power to both 110v and 220v equipment, eliminating ground loops and brownouts.


2014 HT Level 5 Gold


Creative Solutions:


The decision was made to draw the room 4’ wider and 5’ deeper than initially planned and build interior acoustical walls 2’ in from the perimeter boundary wall (3’ on the front wall). This allowed for 2’ between the face of the speaker and the boundary wall behind it, so the speakers are able to perform as if they are freestanding in the room. The extra depth concealed the speakers and the deep acoustic diffusers, maintaining clean architectural elements for the interior designer to work with.

The ceiling was also furred down to hide the HVAC slot registers in the sides of the ceiling soffit, adding to the clean appearance of the design. Lowering the center portion of the ceiling gave the room more character.

Some Auro progression changes were challenging to implement during the course of the project – for example, doubling the number of VOG speakers and repositioning them due to improvements of the developing audio format. Extra effort, additional speakers, amp channels, DSPs, and client approval were needed to stay within spec to meet certification. All engineering pertaining to speaker locations, angles, dispersion patterns, acoustics, and seating position relationships had to be submitted to Auro for certification approval.


2014 HT Level 5 Gold


Calibrations:


After room construction, trim, and speaker enclosure were completed, and prior to acoustic installation, frequency sweeps were run using Goldline RTA to check as-built room response. The results were checked against the original acoustical design plans to see if any modifications needed to be made. Some bass frequencies needed to be better controlled with a bass trap designed to be built into the floor of the first riser. Six Schroeder diffusers were custom-designed and built to replace the specified panels to achieve design criteria and performance.

The entire video chain was calibrated for compliance with Rec709 standards using a Photo Research PR-670 spectrum radiometer.

The LinearX LMS (Loudspeaker Measurement System) was used for near/mid/distant field measurements of full-range loudspeakers. The Goldline RTA measurement system was used for low-frequency room balancing and equalization.

Full-range loudspeakers were calibrated to perform at a flat response curve at the primary listening position while maintaining the flattest possible response curve at other listening positions. Subwoofers are calibrated to deliver a flat response curve at all listening positions. Each individual subwoofer is calibrated separately, as well as in unison, to ensure that frequency response is as equal as possible in all listening positions, even with different environmental variables in each location.


2014 HT Level 5 Gold


Result:


This is the first completed residential Auro-3D system in the country. Because the audio format is so new, processes for small spaces were being written while the project was being built, and changes were being made to the 3D audio standard as this theater was being designed. New acoustic criteria for small-room applications were developed for this system.


Project Partners:


Home Technology Professional
HomeTronics
Dallas

Architect
The Caperton Group
Dallas

Builder
Sharif & Munir Custom Homes
Dallas

Interior Designer
Brette Jacques Interiors
Dallas

Specialty Consultants
Auro Technologies
Corey Scott Walton
Dallas

TM Engineering
Dallas

Cinematech
Addison, Texas

California Audio Technology
Sacramento, California

SH Acoustics
Los Angeles



2 Comments

  1. 2 Jeff Davis 01 Oct
    I heard from a manufacture that this theater was up and running in April, before the Cedia entry deadline. Looks like us Yanks had the first operational system in the world!  It's OK, we still love you Brits
  2. 1 Graham Goodbun 29 Sep
    Hi.
    Nice to see our fellow AV professionals doing a nice job on the other side of the pond. We were first in the UK to install a full Auro3D cinema (been fully operational since July) and had similar challenges and rewrote much of the cinema install manual :-) Wonderful stuff and very very happy clients.

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