Diamond D9 & TDX TECHNOLOGY Owner's Manual page 19

GAIN SETTING BRIEF (cont.)
Note: If precision gain setting of individual crossover channels or sub woofer amplifiers
is needed, choose a sine wave frequency that is in the center of the frequency response of
that output or amplifier. Example: If setting the output level of a low pass crossover
output that has a bandwidth of 30 - 100 Hz, use a 60 Hz test tone to set this output level.
This procedure will give you a system with the maximum signal to noise ratio. It is based
on test tones which are constant, not actual music. Music is not a constant signal and
therefore doesn't clip constantly at certain levels. Because of this, a system that has the
maximum signal to noise ratio may not seem like it plays very loud.
In this case it may be necessary to add some gain overlap to compensate for the low
output of the system. Adding gain to the amplifier will lower the signal to noise ratio of
the system and raise audible distortion, but it will raise the overall output of the system
to a more acceptable level if done correctly.
If the overall output of the system is not satisfactory, retune the system using a -3, -5, or
-6 dB test tone. This will raise the systems signal voltage and gain 3 - 6 dB of output.
Either of these settings are an acceptable compromise. In some cases a -10 dB test tone
is applicable, but not recommended most of the time. When using these test tones to
tune the system, be aware that they may drive the speakers past their mechanical limits.
If this happens, they gains will need to be turned down to protect the speakers from
damage.
If sub output is not satisfactory, but the mids and highs is, adjust by lowering the mids
and highs output level. If the mid and highs output is low, turn the sub gains down. Do
not adjust any of the gains above the maximum undistorted output levels achieved by the
procedure.
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