Room Types - Community ENTASYS Application Manual

SYSTEM DESIGN GUIDELINES
Close to the Audience
Placing an ENTASYS system (or any line array) very close to the audience is generally not recommended. A distance of five
(1.5 m) to six feet (1.8 m) is the minimum that should be considered; ideally the array should be at least ten (3 m) feet from
the closest listener. The sound of a line array at very close range is considerably different from its sound farther back, and is
typically perceived as being overly bass-heavy.
R O O M T Y P ES
Low Ceiling - Short RT (Reverberation Time)
Rooms with low ceilings are not uncommon. These spaces usually lack sufficient height for a point source system to yield the
desired uniformity of SPL across the entire audience area unless augmented by a distributed ceiling system. Distributed ceiling
systems can improve coverage, but localization to the source (performer/presenter) is often lost. This is an excellent
application for an ENTASYS system, which can provide optimal coverage with a limited number of loudspeaker locations.
Figure 27 shows a room with dimensions of 60L x 30W x 12H feet (18.3 x 9.1 x 3.7 m), with a single Full-Range ENTASYS
system on each side of the room. The loudspeakers are located at a height of 9 ft (2.7 m), aimed downward by 4 degrees and
inward by 10 degrees. This same positioning could be accomplished in a room with a ceiling height of less than 10 ft (3.0 m).
A small room such as this would most likely have a reverberation time of 1.0 - 1.5 seconds or less, so the use of a Low
Frequency module is probably not required. (If it is, the Low Frequency module can easily be located below the Full-Range
module.) The entire array can be raised higher, and angled down a bit more, if needed.
The SPL map of the room surfaces and audience area shows a good uniformity, ranging from 100 dB in the very front (and
slightly less at the rear) to 103 dB about one-third of the way back. The wide horizontal radiation excites the side walls in the
front half of the room, a result of the ENTASYS system being placed very close to them; the application of some absorptive
and/or diffusive material on the walls in the immediate vicinity of the loudspeakers would help minimize the sonic coloration of
these close reflections. (The later reflections, which are also lower in level, are often beneficial in increasing intelligibility as
well as the overall SPL.) Reference Page 54, regarding early reflections and their effect on the quality of sound.
There is very little sound being directed toward the area behind and between the loudspeakers. This should yield very good
gain before feedback for microphones being used in this area. If more isolation is required, the loudspeaker can be raised
higher and aimed down more toward the audience area.
Figure 27: SPL Map of Room with Low Ceiling
Community ENTASYS Application Guide - Page 29