User Guide
Sound System Design Reference Manual
Case Study C: Specifications for a
Distributed Sound System Comprising a
Ballroom, Small Meeting Space, and
Social/Bar Area.
1. General Information and Basic Performance
Specifications:
1.1 Ballroom Description: The size of the space
is 33 meters long, 22 meters wide, and 8 meters
high. A stage is located at the center of one short
side, and the room may be used for banquets,
displays, and social events such as dancing.
A distributed (ceiling) system will be used for
general speech/music purposes, as well as
amplification of stage events. For this purpose the
system should be zoned for delay. Reinforced levels
up to 100 dB SPL will be expected, and coverage
should be uniform within 1.5 dB up to a frequency of
2 kHz. The space is normally carpeted, except for
dancing. Reverberation time is minimal.
1.2 Meeting Space Description: This space is
typical of many that will be found in convention and
meeting areas. The size is 8 meters by 5 meters and
3 meters high. A distributed ceiling system is to be
designed, uniform within 1.5 dB up to 2 kHz. Normal
maximum levels are expected to be 85 dB SPL.
1.3 Social Area: This space is of irregular
shape, as shown in the diagram. A foreground stereo
music system is to be specified for this space; no
paging will be required. The system should be
capable of producing levels of 85 dB SPL. There is
also a disco/dance floor area, and a four-
loudspeaker installation should provide levels of
105 dB at the center of the dance floor.
2. Exercises:
Study the attached figures that detail the layout
of distributed systems in general, and pick either the
square or hexagonal layout.
2.1 Ballroom System:
1. Determine quantity and placement of ceiling
loudspeakers that will meet the specification.
2. Determine the power allocation for each
loudspeaker and describe the power distribution
system (70-volt or low-Z).
3. Determine the minimum number of workable
zones for signal delay for stage events.
2.2 Meeting Space System:
1. Determine the model loudspeaker required
and the spacing density in the ceiling.
7-16
Figure 7-13. Ballroom layout. Plan view (A); side section view (B).