15
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 fl at perceived spectrum) is fed from the
instrument to the input of the amplifi er or processor.
The resulting spectrum will show room effects. The para-
metric 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, fi rst choose the aberration to
correct, then match the fi lter to its frequency. Start-
ing with extreme settings 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 cor-
rection frequency and aberration frequency are seen to
coincide. This adjustment of bandwidth and level (+ or
–) will fl atten 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 fl aw.
✦
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 confi rm the fi nal settings. Dial in
the boost or cut amount by ear. Don’t worry if the
fi nal 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
fi nal response of both channels.
10.00
5.00
2.00
-2.00
-5.00
-10.00
10
100
1K
Frequency (Hz)
0
10.00
5.00
2.00
-2.00
-5.00
-10.00
10
100
1K
Frequency (Hz)
0
10.00
5.00
2.00
-2.00
-5.00
-10.00
10
100
1K
Frequency (Hz)
0
�����
���������
���������
��������������������������
�
�
�
�
�
�
�
�
�
�
�
�
��
�
�
��
�
�
�
�
�
�
�������
���
