DESIGN GUIDE: MUSIC AND DRAMA CENTERS
DG 1110.3.120
C H A P T E R 3: ACCESSORY EQUIPMENT
JANUARY 1981
STAGEHOUSE ACCESSORIES-HEARING RELATED
FIGURE 3 - 8 . 4
The materials and details of construction en-
Compensate for low attendance rates.
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closing a Room are critical factors in its perfor-
Alleviate echoes and focused reflections.
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mance acoustically. Reverberant decay is a func-
tion of the net reflective property of boundary
Reduce sound levels emanating from the pit.
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surfaces and the volume in which the sound rat-
tles around. While this is a general Room quality,
However, absorption must be properly used. Its
addition results in lower overall sound levels,
adjustment in specific areas can be an accessory
function.
which may necessitate installation of electronic
amplification. Absorptive material can be fre-
Typically adjustable reflector positions include
quency-selective resulting in unnatural or un-
the region over musicians (either in the stage
balanced attenuation just as non-diffuse reflec-
enclosure or in a forestage canopy for pit or-
tors can intensify a given frequency.
chestra), the region above and between musi-
The common practice of alleviating harshness,
cians and audience (forestage canopy), and trou-
ble spots likely to occur in found space
focused reflections or flutter echoes by hanging
conversions (acute corners, domes and focusing
draperies on one wall, would often yield more
coves). Reflectors should almost always incor-
satisfactory results if diffusion were employed
porate diffusion to scatter reflected waves. This
instead. Long, even reverberation is gained by
is accomplished with convexity and surface
provision of cubic volume in correct proportion
irregularities.
to absorption; adding absorption when it isn't
needed essentially defeats a Music Room's intent.
Absorption devices may be employed for several
purposes:
4. Additive/Subtractive Volume
This is a recent approach to variable reverbera-
Reduce the reverberation time of a large vol-
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tion based on the volume/absorption principle.
ume for adaptation to speech.
Efficient coupling or separation is critical to suc-
Permit rehearsal in a highly reverberant empty
cess. Subtraction is possible by sealing off a por-
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house.
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