When To Use Subwoofers - Community ENTASYS Application Manual

SYSTEM DESIGN GUIDELINES
Low Ceiling, Deep Room - Long RT
The last example of spaces typically encountered is one that is very deep (long) with a low ceiling. The room in Figure 30
differs a bit from the first example shown (in Figure 27), in that it is considerably longer and a bit wider, with dimensions of
90L x 50W x 12H ft (27.3 x 15.2 x 3.7 m). As a result, the reverberation times may be greater.
We chose to use ENTASYS systems along each side wall, comprised of two Full-Range modules on top with one Low
Frequency module on the bottom. These arrays are positioned at a height of 11.25 ft (3.43 m), only 9 inches (22.9 cm) from
the ceiling. The three module array extends almost all the way to the floor. Although the Low Frequency module could have
been omitted, it provides additional directivity control in the low mid-bass frequency region, helping to minimize the potential
for a "boomy" sound.
The coverage across the audience area is uniform. The SPL averages about 104 dB throughout, decreasing to just 101 dB in the
very back. In the very front corners of the audience area the SPL is a bit high at just over 107 dB, but this accounts for less
than 1% of the audience.
Even in a room such as this one, with a relatively long reverb time of approximately 1.5 - 2.0 seconds (potentially longer in the
mid-bass region), intelligibility should be good without acoustical treatment. Reference Page 54, regarding early reflections and
their effect on the quality of sound.
Figure 30: SPL Map of Long Room with Low Ceiling
W H E N TO U S E S U BWO O F E R S
The option of employing subwoofers or low frequency extension loudspeakers with ENTASYS systems will, of course, be
largely dependent on the specific application. ENTASYS systems deliver a frequency response down to 200 Hz, making
additional low frequency extension loudspeakers unnecessary for sound systems intended only for vocal reproduction or
speech playback. For systems used in music reproduction, adding low frequency loudspeakers to increase the system response
to approximately 80 - 100 Hz can result in a more natural sounding system.
Community ENTASYS Application Guide - Page 32