Community ENTASYS Application Manual page 33

SYSTEM DESIGN GUIDELINES
Rooms with Longer Low Frequency RT
In rooms with relatively long reverberation times in the low frequency region, the use of subwoofers and other low frequency
loudspeakers should be approached with caution. Due to the nature of low frequency sound waves, these types of
loudspeakers do not offer the directivity control of ENTASYS, and will radiate low frequency energy into the room in virtually
all directions. Increased low frequency reinforcement – and the resulting increased low frequency reverberation – can have the
effect of masking the perception of higher frequencies, thereby reducing the system's overall intelligibility.
The sound system designer must weigh the benefits of low frequency extension, as compared to the potential for decreased
intelligibility. In some spaces, adding low frequency reinforcement may have a limited impact on intelligibility, while in others it
may be quite detrimental. As always, each space and application is unique.
Suggested Low Frequency Systems from Community
Community offers several high quality, low frequency loudspeaker systems that complement ENTASYS-based systems by
extending low frequency response. These include the Versatile Low Frequency (VLF) Series, VERIS subwoofers, SBS45 and the
iLF218.
VERIS subwoofers are ideally suited to ENTASYS, providing low frequency extension to approximately 45 Hz. The Versatile
Low Frequency (VLF) Series loudspeakers also work well with ENTASYS, particularly where space considerations limit the size
of the loudspeaker enclosures. The dual 8-inch VLF208 can extend the system response to 60 Hz, while the dual 12-inch
VLF 212 can extend system response to 43 Hz. For high SPL requirements, the dual 18-inch iLF218 or the SBS45 with four
15-inch drivers provide high output at low frequencies down to approximately 40 Hz.
Suggested Crossover and EQ Settings
Community suggests the crossover and equalization settings detailed in Table 3 when using these low frequency systems with
ENTASYS. (Regardless of the size or configuration of ENTASYS systems being used with these subwoofers, these processing
parameters should suffice as a starting point.) The overall levels between ENTASYS and the additional subwoofers may need
to be adjusted to achieve the optimal balance of the system.
Directional Low Frequency Systems
In critical applications where additional low frequency reproduction is required, but might otherwise lead to problems with
intelligibility or feedback, the use of directional low frequency loudspeakers and subwoofers may offer a possible solution. A
well designed directional subwoofer system can help prevent low frequency spillage onto stage areas, reducing unwanted bass
buildup and helping to minimize low frequency feedback.
Custom built cardioid arrays or end-fire subwoofer arrays may be constructed using stock low frequency loudspeakers. The
construction of these directional low frequency arrays requires multiple low frequency loudspeaker modules, as well as a multi
-channel DSP (Digital Signal Processor) and multiple power amplifiers to drive each loudspeaker module. The spacing between
the low frequency loudspeakers and the special processing used to drive them is what creates the directivity of these arrays.
Community makes it easy and convenient to design a cardioid or end-fire low frequency array with the use of our
Subwoofer Steering Simulation Software (S4). Using S4, designers can quickly and easily determine the processing
parameters required to build these arrays using Community's VLF-Series or any other subwoofer system. S4 is a useful tool
for predicting and controlling the direction of bass frequencies in a given space. S4 can be downloaded from Community at
www.communitypro.com. When using directional low frequency arrays with ENTASYS, the normally recommended crossover
and EQ settings may not be applicable. Contact Community's TAG Team at 610-876-3400 / 1-800-523-4934 or email
TAGTEAM@communitypro.com for additional information and support.
Community ENTASYS Application Guide - Page 33