Cedar AZX+, Руководство пользователя

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PAGE 11
Q
Coarse adjustment
If you do not know the fundamental frequency, you will need to ‘hunt’ for it.
Alternatively, you may know the frequency, but it does not lie close to one of
the presets.
In both these cases you will wish to adjust the
FREQUENCY
control in coarse
steps. Pressing and releasing the
FREQUENCY
knob toggles between
COARSE
and
FINE
(0.01Hz below 100Hz, 0.1Hz above 100Hz) adjustment
modes. The
COARSE
and
FINE
indicators in the
FREQUENCY
display will tell
you which mode you have selected.
If you are hunting for the fundamental frequency, best results are usually
obtained by starting at the maximum frequency (130Hz) and scrolling
slowly down through the range until you hear the buzz or hum become
significantly attenuated.
Note: You must be careful to find the true fundamental frequency. If the buzz has a
50Hz fundamental frequency, a frequency setting of 100Hz might possibly be of
some audible benefit: it would attenuate the even harmonics, but it would not
attenuate the fundamental itself or any of the odd harmonics. Similarly, a setting
of 25Hz might have some beneficial effect, but it might damage the true signal at
25Hz, 75Hz, 125Hz, and so on. In both cases the processing would be more
effective if 50Hz was correctly selected.
Tracking indicators
The
BRX
+ searches for a buzz fundamental in a small window centred on the
displayed fundamental frequency. The width of this window is approximately 1Hz
at a setting of 50Hz, and increases with increasing frequency. If a consistent buzz
is detected within this window, one or more of the tracking indicators will light.
The top tracking indicator
LED
is a red, downward-pointing arrow which lights if
the displayed fundamental frequency is higher than the detected buzz frequency.
The bottom indicator
LED
is an upward-pointing arrow which lights if the displayed
fundamental frequency is lower than the detected frequency.
If either of these
LED
s is lit, you should use the
FINE
adjustment mode to tune the
fundamental frequency until the central green
LED
lights to indicate that the
algorithm is optimally set.
The tracking system takes approximately two seconds to settle, and will thereafter
automatically track slow fluctuations of the buzz, provided that it remains within
the window. If no consistent buzz is detected in the window, any or all of the
LED
s
will flicker as the algorithm continues to ‘hunt’. Loud musical components that fall
within the window can upset the operation of the tracking system; this effect is
minimised by correct setting of the
BUZZ POWER
control.