Owner`s manual

PAGE 19 Community Solutions™ Owner’s Manual
8 CHOOSING POWER AMPLIFICATION
It is important to select the proper power amplifier output for the loudspeaker. To avoid the potential
for damage and/or less than optimum performance you need to have enough amplifier power but not
too much.
The published power ratings for Community Solutions loudspeakers, as listed in the Technical
Specifications in CHAPTER 16, are only applicable when the loudspeakers are used with an electronic
system controller or processor. COMMUNITY’S WARRANTY CLEARLY STATES THAT “USE WITHOUT THE
APPROPRIATE SYSTEM CONTROLLER IS CONSIDERED ABUSE AND VOIDS THE WARRANTY”.
8.1 General Considerations
There are several things that must be considered when selecting an amplifier for a loudspeaker
system. An obvious but misleading consideration is how loud the system needs to be. This should be
determined, not by amplifier power, but by the correct choice of the loudspeaker or number of
loudspeakers based on their maximum usable acoustic output ratings. Note that maximum ratings for
many loudspeakers do not take distortion into account. Community’s maximum output ratings are
realistically usable because the distortion is well within acceptable levels. In this regard, be
conservative. A loudspeaker system that is more capable than needed will always perform well. A
system that is not capable enough will likely need to be pushed hard enough to distort and may fail.
8.2 Amplifier Power For Use with An Electronic Controller
Assuming the correct loudspeakers have been chosen for the application, the best choice of power
amplifier is a simple consideration when using a dynamic electronic controller for Community
Solutions SLS and SBS. To take full advantage of the electronic loudspeaker controller, a certain
minimum power is required. Too little power will essentially bypass the protection function of the
controller by allowing the amplifier to clip before the controller’s protection circuits are activated. This
can result in damaged loudspeakers, in spite of the sophisticated electronic protection. (Refer to
SECTION 13.3 “Using Lower Power Amplifiers”.)
Based on these considerations, the choice of power amplifier size should be based on the power rating
of the loudspeaker. The nominal impedance of the loudspeaker (e.g. 8 Ohm or 4 Ohm) must be used
in determining an amplifier’s output specification from its manufacturer. Community specifies two
power ratings: “RMS” and “Program”. The “RMS” rating is a measure of the thermal limitations of the
loudspeaker, while the “Program” rating is a measure of the loudspeaker’s capability to reproduce
speech and music.
THE RECOMMENDED POWER AMPLIFIER IS ONE WHOSE RATED POWER APPROXIMATELY MATCHES THE
“PROGRAM” POWER RATING OF THE LOUDSPEAKER. This will provide two important benefits:
1. The controller and PowerSense circuitry will operate properly to protect the loudspeaker.
2. With average power inputs near the loudspeaker’s RMS rating, peak power outputs of 7 dB to
10 dB will be available for the dynamic (peak) content of audio signals.