Although such a system could be tuned via a skillful ear, it is
better to enlist the help of a real-time analyzer. This is a piece of
instrumentation that analyzes the spectrum of any signal received
by the microphone. Pink noise (which has a flat perceived spec-
trum) is fed from the instrument to the input of the amplifier
or processor. The resulting spectrum will show room effects. The
parametric analyzer can then be adjusted to dramatically improve
the typical room response. Correcting the room response will
create a more even, musical, and faster-paced bass performance.
To make an adjustment, first choose the aberration to correct,
then match the filter to its frequency. Starting with extreme set-
tings of the other two controls (highest Q and full cut or boost)
can most easily do this. Then, while watching the spectrum
analyzer, the frequency can be adjusted up and down until
your correction frequency and aberration frequency are seen to
coincide. This adjustment of bandwidth and level (+ or –) will
flatten the response. Caps are provided to seal the parametric
controls once they are optimally set.
Hints:
¤ Live with the system for awhile to learn its bass character. Then
tune to correct its dominant flaw.
¤ Measure the bass of each channel over a variety of positions
encompassing the listening area. Correct for the average
curve of the area.
¤ Use your ears to confirm the final settings. Dial in the boost
or cut amount by ear. Don’t worry if the final setting disagrees
somewhat with the “best” setting according to the spectrum
analyzer.
¤ Adjustment of the parametric equalizer may require further
adjustment of bass level. Juggle the settings of one control
against the other.
¤ It is important to have a good match between the final
response of both channels.
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