Theatre Design & Technology - Oct 1972 - 8

Two of the three sections have built-in stepped seating,
and the third can have either seating or a stage platform.
A platform at the center of the building can be lifted or
lowered by screwjacks to take folding platforms, props,
pianos, seating and so forth to or from the basement storage area. When the walls between the sections are closed,
each section is acoustically isolated. When one or more
walls are drawn back or open, many different stage and
seating configurations become possible: variations of small
stage, proscenium stage, and arena stage configurations for
lectures, film showings, theatrical and musical productions, ensembles, graduation ceremonies, and so on.
The control booth for lighting, sound, and recording is
over the center platform and takes its shape, with three
radiating arms, from the soffit needed for the movable
walls. Catwalks carry mechanical ducts and provide limitless possibilities for lighting, projection, and scenic drops.
Each of the three peripheral concrete stair towers contains
major mechanical ducts and supports a "Y" shaped steel
truss with an intersecting steel truss ring.
Acoustic and theater consultants Bolt, Beranek and
Newman, Inc. were called in at an early stage to advise on
the feasibility of the concept. The original design was developed with their encouragement and, thereafter, their
close cooperation. Research on sound isolation was further aided by a grant from Educational Facilities Laboratories. The following notes are quoted from reports by
Bolt, Beranek and Newman, Inc.

"A. Sound Isolation In this category, the goal has been to
provide a degree of sound isolation between spaces which
will allow simultaneous music activities in the three major
spaces when the auditorium is completely subdivided, and
to provide adequate sound isolation for simultaneous
speech activities for all other configurations. Following
are the major elements which have been incorporated in
the design in order to achieve the above requirements.

2. Double Dual Coil-Wals for air-borne sound isolation between spaces for simultaneous music activities when fully
su bd iv ided.
3. Vibration isolation joints in the floor and roof construction between major auditorium spaces to reduce
structure-borne noise transmission during simultaneous
activities and to prevent "flanking" of the Coil-Wal construction.
4. Provision of "resilient skins" on the auditorium sides
of corridors on level 4, on the walls enclosing the major
trusses, and on the ceiling below the lower control area
and the level 4 corridors. The pu rpose of this construction
is to reduce air-borne and structure-borne noise between
major spaces.

1. Sound diffusing panels on bottoms of catwalks and
ceilings below level 4 corridors and control room in order
to provide sound diffusion and uniform sound distribution throughout the spaces.
2. Sound absorbing treatment on exterior wall surfaces in
order to eliminate formation of delayed sound reflections
(echoes).
3. Fully retractable sound-absorbing draperies on exterior
walls in catwalk area to provide adjustability of reverberation time.
4. Fully upholstered, cloth covered seating throughout
the auditorium in order to provide relatively uniform reverberation for various conditions of occupancy.

ACOUSTICAL REQUIREMENTS

1. Single Dual Coil-Wals for air-borne sound isolation of
simultaneous speech activities when partially subdivided.

B. Room Acoustics In the room acoustics design, consideration was given to the multiple use of the major spaces
and to the various configurations which the space could
assume. Drama, lectures, and music activities have different acoustical requirements and a certain degree of acoustical ability is therefore necessary. Following are the
major recommendations for room treatment which have
been incorporated in the design in order to achieve near
optimum acoustical conditions for the various activities
and space configurations:

C. Mechanical System Noise Control The acoustical success of any auditorium depends on careful control of the
noise produced by the mechanical systems, particularly
the air-handling system. A goal of NC-20 (which is practically inaudible) has been established for this auditorium.
Achievement of this low background noise level will help
to insure good hearing conditions throughout the auditorium for all activities. In order to achieve the goal, the
following recommendations have been incorporated in the
drawings and specifications:
1. Su pply and return air systems are "low velocity" systems.
2. Sound-absorbing duct lining will be provided throughout most of the supply and return air ducts in order to
reduce fan noise transmitted through ductwork into the
auditorium.
3. Sound-attenuating mufflers have been provided in the
duct systems wherever short duct runs make it impossible
to achieve the required fan noise attenuation by means of
duct linings.
4. Vibration isolation has been recommended for all
mechanical equipment which might transmit excessive
vibration into the structure."
" .. LIGHTING
Respective of the program of activity and design parameters set by the architect, the Iighting system becomes a
crucial element in making the performance spaces work.
The fact that these performances spaces are of varied configurations requires that the system be designed to accommodate all of the variations conceived. The ability to see

THEATRE DESIGN AND TECHNOLOGY

OCTOBER, 1972

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