6
551E
552E
/
Diagram 6 - Frequency graph.
Diagram 7 - Range switch action.
AUDIO PRECISION 551E
vs
23 MAY 96 10:02:53
-20.00
-15.00
-10.00
-5.000
0.0
5.0000
10.000
15.000
20.000
AMPL(dBu)
20
100
1k
10k
20k
FREQ(Hz)
Frequency
knob range
AUDIO PRECISION 551E
vs
23 MAY 96 10:09:46
-20.00
-15.00
-10.00
-5.000
0.0
5.0000
10.000
15.000
20.000
AMPL(dBu)
20
100
1k
10k
20k
FREQ(Hz)
1kHz
X0.1
1kHz
X 1
1kHz
X 10
Frequency Knob
Use this knob, in conjunction with
the Frequency Switch, to adjust
the center frequency of the area
affected by the filter band. See
Diagram 6.
Frequency Switch
Think of this as a Frequency knob
multiplier. When you put the
toggle in the X1 position the
range of the Frequency control
corresponds to the numbers
printed around the knob - 100 Hz
to 2kHz. Use this position when
you want to work in the midrange.
The X10 position shifts the
Frequency knob’s range upward
by a factor of 10. The range
becomes 1kHz to 20 kHz; suitable
for high-frequency adjustments.
The X0.1 position moves the
range downwards (10 Hz to 200
Hz), for fine resolution in the low-
frequency area. See Diagram 7.
Before you ask, we want you to
know that we know it seems to
makes no sense that X1 is the top
switch position, X10 is middle,
and X0.1 is bottom. Our resident
circuit guru informs us that there
is no way to wire this toggle
switch so that it works in the
logical order. If you need proof
just look at someone else’s
parametric EQ toggle switch.
