Hafler P7000 3386 fo= R (in k) for .047f cap = R (in k) for .022f cap, 7234 fo, Where: R = fo = desired crossover frequency c = capacitor in farads ex: .047 x 10-6 for .047mf cap, The actual formula is: R = 1 2foc

To calculate the resistor value for a frequency not on the chart use the following:
3386
fo= R (in kΩ) for .047µf cap
= R (in kΩ) for .022µf 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
2πfoc
Butterworth Alignment Q = .707
1% resistors used with 0.047µF capacitors
Butterworth Alignment Q = .707
1% resistors used with 0.022µF capacitors
Frequency R1 R2
20Hz 357kΩ357kΩ
25Hz 287kΩ287kΩ
30Hz 237kΩ237kΩ
35Hz 205kΩ205kΩ
40Hz 178kΩ178kΩ
45Hz 162kΩ162kΩ
50Hz 143kΩ143kΩ
55Hz 130kΩ130kΩ
60Hz 121kΩ121kΩ
65Hz 110kΩ110kΩ
70Hz 102kΩ102kΩ
75Hz 95.3kΩ95.3kΩ
80Hz 90.9kΩ90.9kΩ
85Hz 84.5kΩ84.5kΩ
90Hz 80.6kΩ80.6kΩ
200Hz 35.7kΩ35.7kΩ
300Hz 23.7kΩ23.7kΩ
400Hz 17.8kΩ17.8kΩ
500Hz 14.3kΩ14.3kΩ
600Hz 12.1kΩ12.1kΩ
700Hz 10.2kΩ10.2kΩ
800Hz 9.9kΩ9.9kΩ
900Hz 8.6kΩ8.6kΩ
1kHz 7.15kΩ7.15kΩ
1.2kHz 6.04kΩ6.04kΩ
2.0kHz 3.57kΩ3.57kΩ
3.0kHz 2.37kΩ2.37kΩ
4.0kHz 1.76kΩ1.76kΩ
5.0kHz 1.43kΩ1.43kΩ
6.0kHz 1.21kΩ1.21kΩ
7.0kHz 1.02kΩ1.02kΩ
8.0kHz 909Ω909Ω
– 18 –
Frequency R1 R2
20Hz 169kΩ169kΩ
25Hz 133kΩ133kΩ
30Hz 110kΩ110kΩ
35Hz 95.3kΩ95.3Ω
40Hz 84.5kΩ84.5kΩ
45Hz 75kΩ75kΩ
50Hz 68.1kΩ68.1kΩ
55Hz 61.9kΩ61.9kΩ
60Hz 56.2kΩ56.2kΩ
65Hz 52.3kΩ52.3kΩ
70Hz 48.7kΩ48.7kΩ
75Hz 45.3kΩ45.3kΩ
80Hz 42.2kΩ42.2kΩ
84Hz 40.2kΩ40.2kΩ
90Hz 37.4kΩ37.4kΩ
200Hz 16.9kΩ16.9kΩ
300Hz 11.3kΩ11.3kΩ
400Hz 8.45kΩ8.45kΩ
500Hz 6.65kΩ6.65kΩ
600Hz 5.62kΩ5.62kΩ
700Hz 4.75kΩ4.75kΩ
800Hz 4.22kΩ4.22kΩ
900Hz 3.74kΩ3.74kΩ
1kHz 3.40kΩ3.40kΩ
1.2kHz 2.8kΩ2.8kΩ
2kHz 1.69kΩ1.69kΩ
3kHz 1.10kΩ1.10kΩ
4kHz 845Ω845Ω
5kHz 665Ω665Ω
6kHz 562Ω562Ω
7kHz 487Ω487Ω
8kHz 422Ω422Ω
RESISTOR CHART
The following charts list the resistor values to use for common crossover frequencies.