Owner`s manual
PAGE 33 Community Solutions™ Owner’s Manual
1. As a minimum, you need to use at least a voltmeter along with the maximum output voltage
specification for each piece of electronics. The preferable tool is an oscilloscope that can be
used to observe the signal directly. If neither of these are available, you can use the level or
clipping indicators on each piece of equipment in the signal chain. Without some method of
determining the clipping point for each piece of equipment, you cannot expect to optimize
the gain structure.
2. Before setting gain structure disconnect the loudspeaker(s) from the amplifiers. Do not
disconnect the sense lines for any electronic controllers in the system.
3. The basic procedure is to use a test signal (a sine wave signal is ideal) and set the first piece
of equipment in the signal chain (usually the mixer) so it is just below maximum voltage
output as read on the voltmeter or on equipment’s output meter or just below clipping as
observed on the oscilloscope. Without changing this signal level adjust the level controls on
each piece of equipment following, including the power amplifiers, so it is just below its
maximum output. You will find that the input level controls on the power amplifier will end
up being set anywhere from 10 dB to over 20 dB of attenuation.
NOTES:
a. Due to differences in the capabilities of devices in the signal chain, it may not be
possible to achieve the results exactly as stated.
b. Gain structure should be set after any equalization is set for the system so that any
boosts (which reduce headroom in the equalizer) are taken into account.
c. For each device, make sure it is the output and not the input that is clipping.
d. Always make sure that the electronic controllers go into limiting prior to anything else in
the system going into clipping. In this way the controller’s limiter, rather than a clipped
signal somewhere else in the signal chain, will control the system’s maximum output.
4. Remove the test signal, turn off all equipment and reconnect the loudspeaker(s) and the
system is ready for level balancing, assuming you have more than one loudspeaker. If you
have only one loudspeaker the system should be ready for use.
12.3.1 Residual Noise
The SLS and SBS loudspeakers have high sensitivities which mean that they produce a relatively high
output for a given electrical input. This includes the residual electronic noise of an audio system. By
setting gain structure properly and using high quality professional electronics, this noise should be at
or near inaudibility. Among the noisier electronic devices are 16 bit digital devices such as some
signal delays. They have signal to noise ratios that are only 90 dB. However, if the gain structure is
set correctly this means that, for example, if the system can produce 120 dB SPL at maximum output,
the residual noise should be about 30 dB SPL. This would be acceptable for a quiet recording studio.
If residual noise is a problem, gain structure is usually the culprit – it is never the loudspeakers.
12.4 Level Balancing
Once the system gain structure is set, the level balances can be adjusted. This may mean the levels
between HF and LF sections of a biamplified loudspeaker, a full-range loudspeaker to subwoofer level,
levels between multiple loudspeakers, or between main and delayed loudspeaker array. The idea is to
make the system sound the best it can without using any equalization. This may be done using
acoustic test equipment such as an RTA (real-time analyzer), TEF™ analyzer or similar. You must
always determine the final level balance by listening to a variety of known program material. Level
balancing can also be done entirely by ear if acoustic test equipment is not available. In any case, the
preferred method of adjusting levels for balancing is to use the amplifier input level controls.
IMPORTANT: In order to maintain the system’s dynamic range that was maximized by setting the
proper gain structure, DO NOT TURN UP THE INPUT LEVEL CONTROLS OF ANY OF THE AMPLIFIERS. For