KLING & FREITAG K&F CD 44 Digital System controller User Manual
Page 19
User's manual
K&F CD 44 Digital System Controller
KLING & FREITAG GMBH © 2014
Version 11.6
Page 19 of 77
20
50
100
500
1000
5000
10000
20000
-40
-36
-24
-12
-6
-3
0
2
Frequency in [Hz]
P
o
w
e
r
in
[
d
B
]
FilterType = 'HighP' (Highpass) Freq = 1000Hz
Q = 0.707
Butterworth 1.Ordnung
Q = 0.2
Q = 0.5
Linkwitz-Riley 2.Ordnung
Q = 0.707 (default) Butterworth 2.Ordnung
The resulting filter Q = 0.707 is a 2nd order Butterworth filter and causes attenuation of
3 dB at the cut-off frequency (-3dB @ 1000Hz). Below the cut-off frequency, there is an
attenuation of 12 dB per octave (-12dB/octave).
20
50
100
500
1000
5000
10000
20000
-24
-12
-3
0
10
20
Frequency in [Hz]
A
m
p
li
tu
d
e
i
n
[d
B
]
FilterType = 'HighP' (Highpass)
Freq = 1000Hz
Q = 0.707 (default)
Butterworth -12dB/Oct
Q = 10
A Q higher than 1 causes a level increase at the crossover frequency.
You can choose between a high pass filter 1st or 2nd order. The Q of a 1st order high pass
filter is always fixed. At a 2nd order high pass filter Q is adjustable in steps of 0.001 from
0.2 to 20.
The parameter 'Gain' has no effect with the high pass filters.
The following table illustrates how you can implement the common high and low pass
filters and how many parametric filters you need to do so.
Type of
filter
Slope
Number
of
neces-
sary
PEQs
Q
high- /
low
pass
filter
1
Q
high- /
low
pass
filter
2
Q
high- /
low
pass
filter
3
Q
high /
low-
pass
filter
3
Butterworth
1st ord.
6
dB/
oct.
1
0
-
-
-
Butterworth
2nd
ord.
12
dB/
oct.
1
0.707
-
-
-
Linkwitz-
Riley
2nd
ord.
12
dB/
oct.
1
0.5
-
-
-
Butterworth
3rd ord.
18
dB/
oct.
2
1
0
-
-