DESIGN GUIDE: MUSIC AND DRAMA CENTERS
DG 1110.3.120
C H A P T E R 3: ACCESSORY EQUIPMENT
JANUARY 1981
Coupling has also been accomplished electron-
tion of the Room, or by moving musicians out
ically, using the stagehouse as a reverberant
of the enclosure and sealing it behind them. Ad-
chamber connected by microphones to speakers
dition is possible by two methods with varia-
in the house. The advantage of electronic cou-
tions: physically expanding the volume of Room
pling is ability to turn it off in multi-use Rooms,
increases reverberation time generally, and cou-
so that undue scene change noise is not trans-
pling other volumes in proximity to the source
mitted during drama performances. Air-coupled
increases reverberation of a portion of the fre-
volumes must be mechanically separated, with
quency spectrum.
absorptive draperies added to deaden the space.
There are also issues of fire separation to con-
The sophisticated technology involved tends to
tend with.
limit application to special circumstances arising
from Room configurations dictated by unusual
The practice of closing the proscenium or or-
program goals; the likelihood of such circum-
chestra enclosure and staging small scale music
stances is small and more readily solved by firm
performances in front of it carries with it the need
decision. Although adaptive electronic systems
for reflective surfaces around the musicians.
will probably prove more feasible, consideration
These may be set up on the apron or lowered
of coupled volumes may help avert related
from a forestage canopy. The proscenium clo-
problems.
sure must be more dense and reflective than the
Actually enlarging or decreasing effective Room
typical house curtain.
volume at will is rarely practical. Given a deep
5. Electronics and Sound Systems
upper balcony, it is possible to close it off by
As with demountable shells, it is easier to think
drawing a heavy, specially designed sectional
of electronic components as accessory `equip-
partition between its front row and the ceiling.
ment". They serve three general functions in
Schemes to mechanically raise and lower the
terms of performance acoustics: enhancement
ceiling itself have been plagued with problems
of acoustical seals, integral lighting and me-
of natural acoustic qualities, amplification of
chanical systems and great weight. Annexing
sound, and theatrical sound effects.
adjoining spaces and corridors fails on account
In terms of Room design impact, the first func-
of their contents, and practical dimensions de-
tion (electro-acoustic enhancement) is most sig-
termined by normal use. The coupled volume
nificant, as it deals with objectives that could
must become part of the Room.
otherwise be effected only by physical changes
in the structure. This system's sole purpose is to
The most useful volumes are in proximity to the
increase reverberation time by electronically in-
music source. Their use results in strengthened
troducing very small delays between input and
low frequencies for added "warmth". One of
output. The system must be designed for the
these volumes is the stagehouse itself, con-
Room and should only be undertaken by a qual-
nected through a large proscenium. The instal-
ified acoustician.
lation of a partially "transparent" shell reflects
mid and high frequencies. Low frequencies enter
Amplification (sound reinforcement) raises the
the stagehouse where they reverberate and
level of direct sound radiated into the Room. This
emerge into the house a short time later, effec-
too must be designed by a well-informed spe-
tively lengthening low frequency decay. How-
cialist. Its architectural implications reside in the
ever, the volume must be relatively free of ab-
placement of loudspeakers, the choice of which
sorptive materials, which limits the kind and
must belong to the acoustician. Depending on
quantity of drops stored there.
Room use and configuration, loudspeakers may
Perhaps a more practical possibility is the utili-
be located in a central cluster above the pros-
zation of understage volume in a similar fashion,
cenium, in several groups above the proscen-
with the ability to control absorption. In this case,
ium, on both sides of the proscenium, or distrib-
the stage floor behaves like a drumhead or violin
uted in the house. Improper placement of
body. When the volume is coupled with the
loudspeakers and microphones can destroy the
Room it enhances reverberant field for the au-
usefulness of the Room.
dience near the stage especially, who often suf-
fer from high direct/reverberant ratios. This
An audio effects system provides the aural
method has had application in non-stagehouse
equivalent of visual (lighting and scenic) con-
Rooms, too.
3-53
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