The Design of a 2 way crossover for 4 Ohm loudspeakers    8 Ohm crossover

Frequenzweiche für 2-Weges-System oder Subwoofer If you want to calculate the crossover yourself:
2 way crossover calculator

For a 2 way system or to separate satellites from a subwoofer a 12 dB / octave filter according to the picture on the left should be used. For 8 Ohm systems the values of the following tables are applicable.

To choose a capacitor is straight forward: select the value from the table below and choose a capacitor according to the desired quality level. Standard means: a MKT in series to the tweeter and an unetched electrolytic capacitor in parallel to the woofer (in high powered PA application possibly a MKT). Please take into account the maximum voltage Vac:

Selecting the right coil is a bit more complicated. Important aspects are:

Taking these aspects into consideration, we suggest the coils listed in the table below, indicating coil type, order no and DC resistance.

The colour code indicates the coil's material:
- iron, high power handling
- ferrite, low distortion - even at low volume
- ferrite, T-Core with extremely low distortion
- air, type 1 or 2 with lowest distortion
- large air core coil, type 3 or 4, with lowest distortion

For 4 Ohm loudspeakers:         ... 8 Ohm calculation  

Frequency in Hz 60 90 135 200 275 400 625 900 1200 1500
Cap. C in uF 400 330 200 100 82 68 47 33 22 15
e.g. ClarityCap PWA 4x EUR 30,32 excl. VAT: € 25.48 / $ 28.54 4x EUR 25,54 excl. VAT: € 21.46 / $ 24.04 2x EUR 30,32 excl. VAT: € 25.48 / $ 28.54 EUR 30,32 excl. VAT: € 25.48 / $ 28.54 EUR 25,54 excl. VAT: € 21.46 / $ 24.04 EUR 22,32 excl. VAT: € 18.76 / $ 21.01 EUR 16,18 excl. VAT: € 13.60 / $ 15.23 EUR 9,65 excl. VAT: € 8.11 / $ 9.08 EUR 7,41 excl. VAT: € 6.23 / $ 6.97 EUR 4,97 excl. VAT: € 4.18 / $ 4.68
Coil L in mH 15 10 6.8 4.7 3.3 2.2 1.5 1.0 0.82 0.56
Coils
up to 12 Watt
H71
15 mH
1,2 Ohm EUR 15,01 excl. VAT: € 12.61 / $ 14.13
H71
10 mH
0,87 Ohm EUR 11,21 excl. VAT: € 9.42 / $ 10.55
H71
6,8 mH
0,70 Ohm EUR 9,94 excl. VAT: € 8.35 / $ 9.36
H71
4,7 mH
0,46 Ohm EUR 8,99 excl. VAT: € 7.55 / $ 8.46
L100
3,3 mH
1,1Ohm EUR 18,72 excl. VAT: € 15.73 / $ 17.62
L100
2,2 mH
0,83 Ohm EUR 15,89 excl. VAT: € 13.35 / $ 14.96
L100
1,5 mH
0,62 Ohm EUR 13,06 excl. VAT: € 10.97 / $ 12.29
L100
1,00 mH
0,49 Ohm EUR 11,31 excl. VAT: € 9.50 / $ 10.64
L100
0,82 mH
0,44 Ohm EUR 10,33 excl. VAT: € 8.68 / $ 9.72
L100
0,56 mH
0,36 Ohm EUR 8,94 excl. VAT: € 7.51 / $ 8.41
Coils
up to 25 Watt
H100
15 mH
0,83 Ohm EUR 27,39 excl. VAT: € 23.02 / $ 25.78
H100
10 mH
0,64 Ohm EUR 23,59 excl. VAT: € 19.82 / $ 22.20
H100
6,8 mH
0,46 Ohm EUR 18,62 excl. VAT: € 15.65 / $ 17.52
H71
4,7 mH
0,46 Ohm EUR 8,99 excl. VAT: € 7.55 / $ 8.46
H100
3,3 mH
0,27 Ohm EUR 14,91 excl. VAT: € 12.53 / $ 14.03
L100
2,2 mH
0,83 Ohm EUR 15,89 excl. VAT: € 13.35 / $ 14.96
L100
1,5 mH
0,62 Ohm EUR 13,06 excl. VAT: € 10.97 / $ 12.29
L100
1,00 mH
0,49 Ohm EUR 11,31 excl. VAT: € 9.50 / $ 10.64
L100
0,82 mH
0,44 Ohm EUR 10,33 excl. VAT: € 8.68 / $ 9.72
L100
0,56 mH
0,36 Ohm EUR 8,94 excl. VAT: € 7.51 / $ 8.41
Coils
up to 50 Watt
BS125
15 mH
0,59 Ohm EUR 53,61 excl. VAT: € 45.05 / $ 50.46
BS125
10 mH
0,46 Ohm EUR 45,33 excl. VAT: € 38.09 / $ 42.66
BS125
6,8 mH
0,37 Ohm EUR 43,48 excl. VAT: € 36.54 / $ 40.92
BS125
4,7 mH
0,30 Ohm EUR 41,53 excl. VAT: € 34.90 / $ 39.09
H100
3,3 mH
0,27 Ohm EUR 14,91 excl. VAT: € 12.53 / $ 14.03
H100
2,2 mH
0,21 Ohm EUR 10,82 excl. VAT: € 9.09 / $ 10.18
H100
1,5 mH
0,17 Ohm EUR 9,39 excl. VAT: € 7.89 / $ 8.84
L140
1,00 mH
0,30 Ohm EUR 18,72 excl. VAT: € 15.73 / $ 17.62
L140
0,82 mH
0,26 Ohm EUR 17,74 excl. VAT: € 14.91 / $ 16.70
L140
0,56 mH
0,2 Ohm EUR 15,99 excl. VAT: € 13.44 / $ 15.05
Coils
up to 90 Watt
PA-Trafo
mo-123200
0,12 Ohm EUR 72,56 excl. VAT: € 60.97 / $ 68.29
PA-Trafo
mo-125490
0,19 Ohm EUR 26,12 excl. VAT: € 21.95 / $ 24.58
PA-Trafo
mo-125470
0,16 Ohm EUR 24,94 excl. VAT: € 20.96 / $ 23.47
H140
4,7 mH
0,26 Ohm EUR 28,37 excl. VAT: € 23.84 / $ 26.70
H140
3,3 mH
0,19 Ohm EUR 26,51 excl. VAT: € 22.28 / $ 24.95
H140
2,2 mH
0,14 Ohm EUR 20,67 excl. VAT: € 17.37 / $ 19.45
H140
1,5 mH
0,11 Ohm EUR 17,74 excl. VAT: € 14.91 / $ 16.70
L140
1,00 mH
0,30 Ohm EUR 18,72 excl. VAT: € 15.73 / $ 17.62
L140
0,82 mH
0,26 Ohm EUR 17,74 excl. VAT: € 14.91 / $ 16.70
L140
0,56 mH
0,2 Ohm EUR 15,99 excl. VAT: € 13.44 / $ 15.05
Coils
up to 165 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 72,56 excl. VAT: € 60.97 / $ 68.29
PA-Trafo
mo-125490
0,19Ohm EUR 26,12 excl. VAT: € 21.95 / $ 24.58
PA-Trafo
mo-125470
0,16Ohm EUR 24,94 excl. VAT: € 20.96 / $ 23.47
PA-Trafo
mo-125450
0,14Ohm EUR 22,32 excl. VAT: € 18.76 / $ 21.01
BT140
3,3 mH
0,22 Ohm EUR 75,64 excl. VAT: € 63.56 / $ 71.19
BS140
2,2 mH
0,16 Ohm EUR 35,77 excl. VAT: € 30.06 / $ 33.67
BS140
3,3 mH
0,12 Ohm EUR 32,95 excl. VAT: € 27.69 / $ 31.01
H140
1,0 mH
0,08Ohm EUR 15,89 excl. VAT: € 13.35 / $ 14.96
L200
0,82 mH
0,16 Ohm EUR 37,72 excl. VAT: € 31.70 / $ 35.50
L200
0,56 mH
0,11 Ohm EUR 30,22 excl. VAT: € 25.39 / $ 28.44
Coils
up to 275 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 72,56 excl. VAT: € 60.97 / $ 68.29
T250
10 mH
0,16 Ohm EUR 193,98 excl. VAT: € 163.01 / $ 182.57
T250
6,8 mH
0,12 Ohm EUR 184,24 excl. VAT: € 154.82 / $ 173.40
T250
4,7 mH
0,08 Ohm EUR 170,59 excl. VAT: € 143.35 / $ 160.56
T200
3,3 mH
0,10 Ohm EUR 103,33 excl. VAT: € 86.83 / $ 97.25
BT140
2,2 mH
0,12 Ohm EUR 69,89 excl. VAT: € 58.73 / $ 65.78
BT140
1,5 mH
0,09 Ohm EUR 58,44 excl. VAT: € 49.11 / $ 55.00
L200
1,0 mH
0,18 Ohm EUR 42,40 excl. VAT: € 35.63 / $ 39.91
L200
0,82 mH
0,16 Ohm EUR 37,72 excl. VAT: € 31.70 / $ 35.50
L200
0,56 mH
0,11 Ohm EUR 30,22 excl. VAT: € 25.39 / $ 28.44
Coils
up to 500 Watt
T250
15 mH
0,17 Ohm EUR 235,90 excl. VAT: € 198.24 / $ 222.02
T250
10 mH
0,16 Ohm EUR 193,98 excl. VAT: € 163.01 / $ 182.57
T250
6,8 mH
0,12 Ohm EUR 184,24 excl. VAT: € 154.82 / $ 173.40
T250
4,7 mH
0,08 Ohm EUR 170,59 excl. VAT: € 143.35 / $ 160.56
T200
3,3 mH
0,10 Ohm EUR 103,33 excl. VAT: € 86.83 / $ 97.25
T200
2,2 mH
0,09 Ohm EUR 88,61 excl. VAT: € 74.46 / $ 83.40
T200
1,5 mH
0,09 Ohm EUR 75,94 excl. VAT: € 63.82 / $ 71.47
L250
1,0 mH
0,12 Ohm EUR 61,41 excl. VAT: € 51.61 / $ 57.80
L250
0,82 mH
0,10 Ohm EUR 58,39 excl. VAT: € 49.07 / $ 54.96
L250
0,56 mH
0,08 Ohm EUR 48,64 excl. VAT: € 40.87 / $ 45.78

Both, the two coils and the two capacitors, should have the values indicated in the table. A subwoofer filter requires only one capacitor and one coil.

The coil in parallel to the tweeter or satellite needs to handle only half / a quarter of the power, if the crossover frequency is higher than 400/800 Hz.

Hint:

1) 18 and 24 dB / octave crossovers only make sense when the driver's exact characteristics are known!

2) This is certainly not a high-end-crossover. Such a crossover needs to be designed according to the drivers used. A good example is the Cauchy-crossover.
 

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