Theatre Design & Technology - Spring 1985 - 7

LETTERS TO THE EDITOR
To the Editors:
I read wilh interest D. Andre"· Gibbs' anicle
entitled "Noise Control and Hearing Proleclion
for the Scene Shop" in the Fall 1984 issue. I agree
wholeheanedly with i\1r. Gibbs that hearing protection is of extreme imponance in the theatre.
Noise exposure is a '·ery real problem not only in
scene shops, but on stage as well.
I must disagree, however, wilh the author
when he states: "The human body will tolerate
infrequent high noise levels of shon duration
,,"ithout permanent damage.'· I refer the reader
10 the publication issued by Bruel & Kjaer Instruments entitled "Do We i\leasure Damaging Noise
Correclly?" It has been shown that high level
shon duration impulses are in facl far more damaging to hearing than long duration steady noise.

As O\1r. Gibbs shows, hearing loss begins and
remains most severe in the 4kHz 10 6kHz region.
The B & K paper shows how the peak energy in
impulsive sounds such as hammer blows, pneumatic nailing machines, power saws and the like
not only is higher in level than lhat read by an ordinarv sound level meter, but is also concentrated
in the 4kHz 10 6kHz region. It is the impulsive
pan of the noise lhat really does the damage.
Visualize the teeth on the blade of a power
saw as the blade spins. Each time a lOoth strikes
the material being cut a sound is produced. The
sound is high in level bUI, because the 100th
strikes so rapidly, the sound is of very shon duration. It is the shon duration that causes the reduction in perceived loudness. The loudness is

perceived in the brain; the ear still receives and is
affected by the high level impulse. If your ears
ring or if you experience a temporary threshold
shift after exposure 10 sound of any perceived
level, no matter what its duration, damage is likely to be taking place.
As a theatrical sound consultant, I personally
wear hearing protection whenever I am exposed
to even moderately loud sounds. I especially protect my ears when I am operating any type of
power 1001, driving nails, or doing anything that
generates impulsive sounds.
Cordially,

To lhe contrary, we have recently seen some
new theatre equipment designs which were not
only unsafe but, in addition, impossible 10 build
as drawn and specified. This, nOI because of lack
of innovations, but rather because these innovations defied good engineering principles. Many
designs have been prepared by expens in other
theatre-related areas without the benefit of solid
engineering. We have seen movable systems,
which have been self-destruct (meaning that the
motor could rip the rigging apan in case of accidental jamming-this has happened with disastrous results) and none of those employed single
mode failure-proof design (meaning that the failure of anyone component should not drop the
load and cause an accident). Even more surprising-unsuspecting design professionals often pUI
their seals of approval 10 such designs, thus participating in lhe responsibilily for their function
and safety.
Multi-purpose theatres usually require more
mechanization than the theatres built for a single
purpose. This mechanization does not probe the
limits of engineering knowhow, but is mostly
confined 10 proper consideration and execution
of lhe basics. Many successful theatre mechanisms were built before the computer age and
without the help of integrated circuitry and computers. The approach, however, was differentdesigns and problems were worked out on paper
by experienced engineers before the metal was
cut. Procedures like this may not be necessary for
scenery design, but when one builds permanent
theatre equipment that has 10 operate year after
year, there is no substitute for sound engineering.
This is how the reliable facilities have been built
-The Radio City stage lifts, the movable ceiling
in Juilliard School of Music, orchestra lifts and
seating wagon arrangement in Empire State Theatre-ali were done by methods proven in other
related industries.
While the design of customized theatre equipment does not probe the limits of engineering

knowledge, it requires a coordinated effon by the
mechanical, electrical and structural engineering
disciplines 10 transfer the designer's ideas inlO
working realities. It is not sufficient 10 write a
"performance" specification, which forces a
manufacturer 10 assume responsibility for a system designed by consultants. Not only is the legality of this procedure questionable, it also delays the design of equipment for coordination
with the rest of the building. This can later result
in costly modifications and "extras" or sometimes in omission 0 f specific systems which would
be essential for thealre operation as envisioned in
the initial design.
It is the defiance of basic engineering principles, not lack of innovative talent, which has
created problems in new theatres. Some of the facilities envisioned by designers to change the
space, to adjust the acoustical characteristics, to
modify the seating capacity and 10 mechanize the
stage, may not be operational because they have
failed 10 fulfill their intended funtions or because
they are 100 cumbersome 10 operate. The others
are still there, hanging over people, many of them
held in place only by a single linkage without an
independent safety backup.
In view of recent building failures, which have
involved relatively simple structures, this is a very
serious concern.
Except for function, the design and safety of
the theatre machinery is based on the same principles as the design and safety of other mechanical /structural equipment. Why not learn from
successful projects elsewhere? There is no need
for failures. However, a successful, functional,
economical and sa fe design can be only achieved
if the innovative ideas are carried out by proper
engineering knowledge and discipline.
Very truly yours,
DlafSoor
Olaf Soot Associates, P.c.
Greenwich, CT
ew York, Y

Farrel M. Becker
Audio Artistry
KensinglOn, Maryland

To the Editors:
It was interesting to read Mr. John von Szeliski's design repon on lhe Orange CounlY Performing Ans Center (Summer, 1984). On the
other hand, the edilor's note regarding the potential problems was rather concerning and, in
view of recent theatre design hislOry, cenainly
justified.
It has been our experience that the success and
safety of many multi-form theatres depends to a
large extent on the proper design and engineering
of its major mechanical elements. It is an area,
of course, where we have done a great amount of
work and lherefore, I would like to comment on
some of lhe common problems thaI have plagued
the theatre design and for some reason do not get
much allention.
Much emphasis in present-day lheatre design
is placed on brainslorming sessions or "squatters." They are cenainly necessary, and good
ideas can be generated by frank and open exchanges between talented individuals, but only as
long as they are based on technical realities.
The problem in our thealres, however, has not
been the lack of ideas, but the gap between lhe
ideas and their technical execution. The mysterious "·ord "technology" has been substituted for
the word "engineering" and it usually means
opinions or gadget ry rather lhan crealing a hard,
well balanced and well documented design. The
design budgets seem 10 disappear during the discussion phase and little is lefl 10 develop ideas
into workable realities.
When the Radio City i\lusic Hall was designed
and built, lhe "lechnology" cenainly was not as
advanced as it is now and machinery or electrical
control systems were not available "off the shelf."
The brass-engraved control panel on stage
right and the controls may look antiquated now.
However, when one, knowledgeable in mechanical design and engineering, walks down to lhe lifl
pit and machine room, one can see the thoroughness of cvery del ail and can understand the
knowledge and care that wCnt inlO this design.

USITT/Spring 1985/Theatre Design & Technology

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