Rev 2.0, 9/15/94
3
2.4 Tuning the EQ/Notch Filter
For both boost and cut, the SX201's parametric equalizer/notch
filter is intended to be put to work on specific frequencies. To
"tune" the equalizer, use full boost to make the frequency easily
heard and identified.
To find a particular frequency "by ear" (the method used by
everyone who doesn't have a real-time analyzer), turn the
cut/boost control all the way up to +15dB (be very careful of
feedback if you are listening on a loudspeaker!). Set the
bandwidth for about .3 octave. Tune the frequency control until
you distinctly hear the part of the sound you wish to control.
Then, adjust the cut/boost control for the appropriate amount of
change, and readjust the bandwidth control if necessary.
To notch out interference like 60Hz hum, follow the procedure
above to get an approximate setting for the frequency control.
Then, to fine tune the notch for the best possible rejection of the
interference, turn the cut/boost control all the way down to -
30dB. Very carefully adjust the frequency control for minimum
hum. Then reduce the bandwidth to about .2 octave, and
readjust the frequency control for minimum hum. Repeat this
process until the narrowest possible bandwidth is achieved.