Owner`s manual

PAGE 32 Community Solutions™ Owner’s Manual
12 ACOUSTICAL ADJUSTMENTS
Once the loudspeaker has been set-up or installed and connected according to the configuration you
need, it is ready for acoustical adjustments.
12.1 Initial Testing
The following procedures are designed to prevent damage to the loudspeaker during initial testing of
the system.
1. Before powering up any equipment, turn down the input level controls on the power
amplifiers and set other level controls to nominal operating positions. If you don’t know
what those positions are, setting sliders about half-way up and rotary controls to their 12
o’clock or half-way position is usually a safe bet.
2. Turn on all the electronics for the system by following the proper sequence for power up
that is universally accepted for professional audio systems. This means turn on the system
in “signal chain order” starting with the input equipment and continuing in order along the
chain with the power amplifiers being the last items to be powered up. This avoids
electronic start-up transients or spikes that some equipment generates. These spikes
generally consist of a DC (direct current) pulse that can be intense enough to overload
subsequent equipment, including the loudspeaker, and cause instantaneous and permanent
damage to that equipment. This procedure should be followed EVERY TIME a system is
turned on.
NOTE: When turning off a system, do it in the reverse order, beginning with the power
amplifiers first and the input equipment last.
3. Apply an input signal to the system. This could be a test signal or program material from a
tape, CD, or tuner. Using equipment level indicators, a voltmeter, and/or a test headset
verify that the signal chain is operating properly up to the input of the power amplifier(s).
You may have to re-adjust controls as set in step 2 to get normal signal levels through to
the amplifier input(s).
4. If the signal chain tests OK, turn up the input levels to the amplifier(s) and you should hear
your input signal reproduced through the loudspeaker. It should be clean and clear. If
using biamplification and/or subwoofers the sound may not be balanced between the high
and low frequencies, but this is corrected in final tuning.
5. If all is well you are ready for the final adjustments to the system.
12.2 Final Adjustments
There are two primary things to consider when making final adjustments on a system: electronic gain
structure and loudspeaker level balancing. The gain structure of a system will determine the dynamic
range of a system or the ratio of the softest to loudest usable sounds. The softest sounds will be
limited by the amount of system noise and the loudest sounds by noticeable distortion or clipping.
Loudspeaker level balancing includes only those systems where there is more than one loudspeaker.
This includes systems where loudspeakers reproduce different frequency ranges (e.g. biamplified
loudspeakers or a full-range loudspeaker with a subwoofer) or systems where multiple loudspeakers
reproduce the same frequency range, (e.g. arrays of multiple loudspeakers or main and delayed
loudspeakers).
12.3 Electronic Gain Structure
Detailed information on how to set electronic gain structure is beyond the scope of this manual.
However the following are VERY general guidelines that may be helpful.