How They Did It: Professional-Grade Screening Room
This homeowner, who works for a major Hollywood studio, wanted a room where he could view Digital Cinema Packages (DCPs) and dailies during evenings and weekends without traveling to his studio offices. The room also needed to serve as a home theater for the purpose of viewing TV, Apple TV, Xbox, and Blu-ray content.
CEDIA member Bradford Wells + Associates, based in Los Angeles, created a pro-quality screening room that earned the Level V Bronze Technical Design award for Home Theater in CEDIA’s 2014 Electronic Lifestyles® Awards competition.
Technical Highlights:
The whole room was fully sound-isolated using resilient construction and vibration-damped sheet rock layers. It has a 12-ft.-6-in.-wide Cinemascope screen with electronic horizontal side screen masking and an acoustically transparent screen.
The room is fully DCI (Digital Cinema Initiatives) compliant, including a DCI-compliant projector from NEC and a cinema media server from Doremi. The projector is a small-footprint digital cinema projector housed in a custom hush box enclosure at the back of the room.
The room's dimensional challenges called for a speaker with the least possible depth. It was decided that a planar-type front-channel and surround-channel speaker was the obvious pick. At the same time, the planar-type speakers had to have studio-grade power handling capacity and a flat frequency response.
The custom "hush box" that housed the projector also had to meet required special ventilation and noise-isolation parameters consistent with the low noise floor of the room. Bradford Wells + Associates engineered a sophisticated audio system, including Wisdom Audio speakers and quad JL Audio subwoofers.
The equipment racks housing the digital cinema server, room EQ, eight-channel surround preamp, power amplifiers, source equipment, and control equipment were all tucked away neatly next door in an air-tight, air-conditioned, acoustically controlled closet with studio-grade tech power.
Challenges:
The project began as a remodel of an existing media room. The original space was small and cramped, so Bradford Wells + Associates worked with the theater consultant and the builder to thoroughly redesign the structure of the room. The front half of the floor was dropped 18” into the crawl space to make room for a riser scheme, and the front wall was pushed back into what was originally a ventilation closet.
Equipment had to be fit in without taking away any more room length, width, and height than was absolutely necessary. To compensate, all room equipment and acoustical materials had to be dimensionally scrutinized and made to work. From the acoustical absorbers and diffusers, to the HVAC system ducting, to the audio and video equipment, everything had to fall within the room's established dimensional, electrical, and acoustical spec.
One of the challenges of the electronics package was the integration of all the consumer gear, including Blu-ray, satellite, and more, with the digital cinema equipment. The 7.1 DCI audio signal was run through a multi-channel D-to-A converter and then into the 7.1 channel analog input of the Marantz decoder. The team had to implement bass management externally using an Ashly 8x16 digital audio processor. The Ashly unit also ran the Wisdom bi-amplified speaker crossovers and full room correction equalizations.
Calibration:
The NEC NC900C Digital Cinema Projector was calibrated with a Photo Research PR-655 Spectroradiometer and a JETI Specbos 1211 Reference Spectroradiometer. The projector was calibrated to meet DCI specification (white point x=0.314, y=03.351, Y=14 fL, DCI color gamut, Gamma 2.6) for playback of DCPs. Two separate MCGD (Measured Color Gamut Data) files were crested to accommodate the two necessary color correction for both 2D and 3D projection through active shutter glasses. For consumer HD source material, the projector was calibrated to meet REC 709 requirements (x=0.313, y=0329, Y=14 fL, REC 709 color gamut, Gamma 2.2).
The room was carefully measured using both impulse response and FFT analysis with 4-microphone spatial averaging. All corrections were meticulously implemented in a digital high-resolution equalizer. The team also listened to the results and fine-tuned the whole system with an eye toward 2-channel audiophile-grade performance as well as a high-impact and dynamic multi-channel cinematic experience. The calibration team comprised veterans of THX, Technicolor, and the Academy of Motion Picture Arts & Sciences.
sursa: cedia.net/
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