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JBL
at the Academy of Motion Picture Arts and Science
(1990 -1991)
JBL
participated in a substantial remodeling of the loudspeaker systems
in the Samuel Goldwyn Theater of the Academy of Motion Picture Arts
and Sciences during 1984. Because of the success of that work, JBL
was asked again to participate in the design and layout of a new
sound system which was installed as part of the complete remodeling
of the Academy's theater-lobby complex during 1990.
The scope of the remodeling required that the Goldwyn Theater be
taken down to its structural members and virtually rebuilt from
the ground up. The Technical Committee of the Academy set new standards
for both sound and projection quality, and all equipment in the
booth was disassembled, and either replaced or rebuilt.
The Goldwyn Theater is used for membership screenings throughout
the year as well as for special events which often include live
music. For these purposes, the stage was enlarged, and seating in
the rebuilt theater was reduced from 1106 to just over 1000.
A complete floor to ceiling wall was built for the screen loudspeakers,
and the five screen channels were relocated for slightly wider presentation.
The new systems follow the same flat power concept as before, with
the substitution of JBL's new VGC (Vented Gap Cooling) Model 2226H
low frequency transducers in place of the older 2225H's, and the
replacements of the 2445J high frequency drivers with the newer
2450J.
All screen system power amplifiers are located behind the screen
and are driven by line level signals from the booth. Bridged monitor
feeds back to the booth provide the projectionist with immediate
feedback.
Another important change in these systems was the use of low pass
filtering of the bottom set of dual woofers in each screen channel
so that they rolled off above 325Hz. This had earlier been determined
by the Technical Committee in listening tests, and it provides for
smoother overall transistion between low frequency and high frequency
portions of the screen systems throughout the house.
While the older 4618 subwoofers had performed admirably for six
years, it was time for a change to the new JBL TCB (Triple Chamber
Bandpass) design. Four of these dual driver systems were located
at the bottom of the loudspeaker wall adjacent to the stage which
ensures quarter-space loading, resulting in maximum output in the
20 to 25Hz range.
Because of the Goldyn Theater's volume of 5660m3, compression driver
surround loudspeakers were specified. Due to the remodeling, the
available space for surrounds behind the stretched fabric wall panels
was often as small as 25cm in depth. A new system had to be designed
for the purpose, and JBL came up with a combination of the 2344
100°/100° horn and the 4646 low frequency system, which
provided the appropriate response and acoustical output capability.
Sixteen of these units were specified, six on each side wall and
four on the back wall. In addition, four older 4673 systems were
retained in the ceiling to provide good coverage in the center of
the house. Four 8330's were specified for soft mounting just inside
the main entrances to the theater.
In order to make the most of such surround density, it was felt
necessary to drive them in symmetrical pairs so that levels could
be tailored for smoothest surround coverage. Thus, six stereo amplifiers
are deicated to the surrounds, making it possible to reconfigure
the system for split surround use.
In addition to the comprehensive motion picture system, the fabric
panels flanking the screen house four JBL Concert Series Model 4873
three-way systems. These are triamplified and are used for speech
and music reinforcement at special events. A Soundcraft console
is permanently located at the sound and lighting area about two-thirds
into the house.
The Academy's Little Theater was also remodeled and outfitted with
three 4675 systems abnd a single 4688 TCB subwoofer. Six 8330 systems
are used for the surround channel.
Remodeling of the main and mezzanine lobbies included dens arrays
of JBL Industrial Series Models 8110 and 8140 ceiling loudspeakers
which are flexibly zoned so that announcements can originate at
many points in the main lobby.
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