Hafler P7000 - Manual (Page 21)

To calculate the resistor value for a frequency not on the chart use the following:
3386
fo
= R (in k
Ω
) for .047
µ
f cap
= R (in k
Ω
) for .022
µ
f cap
7234
fo
Where: R =
Ω
fo = desired crossover frequency
c = capacitor in farads
ex: .047 x 10-6 for .047mf cap
The actual formula is: R =
1
2
π
foc
Butterworth Alignment Q = .707
1% resistors used with 0.047
µ
F capacitors
Butterworth Alignment Q = .707
1% resistors used with 0.022 µ F capacitors
Frequency R1 R2
20Hz 357k
Ω
357k
Ω
25Hz 287k
Ω
287k
Ω
30Hz 237k Ω 237k Ω
35Hz 205k Ω 205k Ω
40Hz 178k Ω 178k Ω
45Hz 162k Ω 162k Ω
50Hz 143k Ω 143k Ω
55Hz 130k Ω 130k Ω
60Hz 121k Ω 121k Ω
65Hz 110k Ω 110k Ω
70Hz 102k Ω 102k Ω
75Hz 95.3k
Ω
95.3k
Ω
80Hz 90.9k
Ω
90.9k
Ω
85Hz 84.5k
Ω
84.5k
Ω
90Hz 80.6k
Ω
80.6k
Ω
200Hz 35.7k
Ω
35.7k
Ω
300Hz 23.7k
Ω
23.7k
Ω
400Hz 17.8k
Ω
17.8k
Ω
500Hz 14.3k
Ω
14.3k
Ω
600Hz 12.1k
Ω
12.1k
Ω
700Hz 10.2k
Ω
10.2k
Ω
800Hz 9.9k
Ω
9.9k
Ω
900Hz 8.6k
Ω
8.6k
Ω
1kHz 7.15k
Ω
7.15k
Ω
1.2kHz 6.04k
Ω
6.04k
Ω
2.0kHz 3.57k Ω 3.57k Ω
3.0kHz 2.37k Ω 2.37k Ω
4.0kHz 1.76k Ω 1.76k Ω
5.0kHz 1.43k Ω 1.43k Ω
6.0kHz 1.21k Ω 1.21k Ω
7.0kHz 1.02k Ω 1.02k Ω
8.0kHz 909 Ω 909 Ω
– 18 –
Frequency R1 R2
20Hz 169k
Ω
169k
Ω
25Hz 133k
Ω
133k
Ω
30Hz 110k Ω 110k Ω
35Hz 95.3k Ω 95.3 Ω
40Hz 84.5k Ω 84.5k Ω
45Hz 75k Ω 75k Ω
50Hz 68.1k Ω 68.1k Ω
55Hz 61.9k Ω 61.9k Ω
60Hz 56.2k Ω 56.2k Ω
65Hz 52.3k Ω 52.3k Ω
70Hz 48.7k Ω 48.7k Ω
75Hz 45.3k
Ω
45.3k
Ω
80Hz 42.2k
Ω
42.2k
Ω
84Hz 40.2k
Ω
40.2k
Ω
90Hz 37.4k
Ω
37.4k
Ω
200Hz 16.9k
Ω
16.9k
Ω
300Hz 11.3k
Ω
11.3k
Ω
400Hz 8.45k
Ω
8.45k
Ω
500Hz 6.65k
Ω
6.65k
Ω
600Hz 5.62k
Ω
5.62k
Ω
700Hz 4.75k
Ω
4.75k
Ω
800Hz 4.22k
Ω
4.22k
Ω
900Hz 3.74k
Ω
3.74k
Ω
1kHz 3.40k
Ω
3.40k
Ω
1.2kHz 2.8k
Ω
2.8k
Ω
2kHz 1.69k Ω 1.69k Ω
3kHz 1.10k Ω 1.10k Ω
4kHz 845 Ω 845 Ω
5kHz 665 Ω 665 Ω
6kHz 562 Ω 562 Ω
7kHz 487 Ω 487 Ω
8kHz 422 Ω 422 Ω
RESISTOR CHART
The following charts list the resistor values to use for common crossover frequencies.