DG 1110.3.120
DESIGN GUIDE: MUSIC AND DRAMA CENTERS
JANUARY 1981
CHAPTER 4: ACOUSTICAL CONSIDERATIONS
4-3.1. The quantities given are for multi-use and
drama Rooms. Large theaters follow these same
rules. Very small theaters could use 4 borders,
8 legs, and 8 tabs. Where only occasional use
will be made of the rigging, the spacing of sets
can be increased to 8 inches or 12 inches, which
are also standard spacings. In no case should
the number of sets in a fly loft drop below 30.
Rooms intended for symphonic concert music
alone may not need any soft goods for normal
uses if the stage is totally masked with a per-
manent concert shell. Standard practice is to
hang portable lights and masking inside the per-
manent shell for popular entertainment and am-
plified music. Winch sets and counterweight sets
are frequently provided which drop through the
orchestra shell to pick up these portable pieces.
1. Permanent Architecture
1.
Gridiron and access
2.
Loft block beams
Head block beams
3.
4.
Loading gallery under head block beam
SAMPLE NOISE SOURCE INTENSITY LEVELS
FIGURE 4-4.1
Fly galleries; each side with pin rails
5.
6.
Counterweight pit with locking rail
2. Permanent Rigging
4-4. ACOUSTICAL
1. Fire curtain or deluge curtain
CONSIDERATIONS
2. T-Track counterweight sets, 6 inches on
center for the full depth of the stage
3. Hemp lines for spot lines and electric pickups
4. Hemp sets for masking and special uses
A synopsis of the most important acoustical con-
3. Soft Goods
cepts is presented here. Listening requirements
determine acoustic parameters for volume, ab-
1.
House curtain
sorption, background noise, partition isolation,
2.
Portal header or "teaser"
reflection patterns and audience-to-performer
3.
Portal legs or "tormentors"
relationships. These in turn influence design de-
4.
5 borders, 10 legs, and 10 tabs black velour
cisions related to building site, Room scale, ma-
5.
Full stage blackout drop, black velour
terials of construction, Room decor, shapes of
6.
Full stage black scrim, black sharkstooth
surfaces, suspended reflector locations, HVAC
scrim
air velocities and system treatment, location of
7. Full stage natural muslin cyclorama
ancillary spaces and loudspeaker placement.
8. Full stage black velour cyclorama
Speech intelligibility is essential for a Drama
A portable demountable concert shell consists
Room. This can be achieved by keeping the vol-
of a ceiling and walls all around the sides and
ume of the Room low in relation to seating area
back of the stage. The ceiling is usually hung
and placing reflecting surfaces in locations that
from standard counterweight sets. The walls are
will direct early high frequency reflections to all
usually supported on rolling castered units and
listeners.
are stored in the wings when not in use. Note
that the permanent storage space for a shell
Background noise must be kept low enough
could be 500 square feet. The ceiling panels must
to allow listeners to comfortably perceive aver-
align with the electric pipes so that the concert
age speech sound pressure levels. Continuous
can be lighted through the gaps between panels.
background noise from mechanical or electrical
4-14
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