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 27,50 excl. VAT: € 23.11 / $ 25.65 4x EUR 23,15 excl. VAT: € 19.45 / $ 21.59 2x EUR 27,50 excl. VAT: € 23.11 / $ 25.65 EUR 27,50 excl. VAT: € 23.11 / $ 25.65 EUR 23,15 excl. VAT: € 19.45 / $ 21.59 EUR 17,39 excl. VAT: € 14.61 / $ 16.22 EUR 12,59 excl. VAT: € 10.58 / $ 11.74 EUR 9,25 excl. VAT: € 7.77 / $ 8.63 EUR 7,16 excl. VAT: € 6.02 / $ 6.68 EUR 4,76 excl. VAT: € 4.00 / $ 4.44
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 16,90 excl. VAT: € 14.20 / $ 15.76
H71
10 mH
0,87 Ohm EUR 14,05 excl. VAT: € 11.81 / $ 13.11
H71
6,8 mH
0,70 Ohm EUR 15,00 excl. VAT: € 12.61 / $ 13.99
H71
4,7 mH
0,46 Ohm EUR 13,50 excl. VAT: € 11.34 / $ 12.59
L100
3,3 mH
1,1Ohm EUR 17,25 excl. VAT: € 14.50 / $ 16.09
L100
2,2 mH
0,83 Ohm EUR 14,35 excl. VAT: € 12.06 / $ 13.39
L100
1,5 mH
0,62 Ohm EUR 11,45 excl. VAT: € 9.62 / $ 10.68
L100
1,00 mH
0,49 Ohm EUR 9,70 excl. VAT: € 8.15 / $ 9.05
L100
0,82 mH
0,44 Ohm EUR 9,20 excl. VAT: € 7.73 / $ 8.58
L100
0,56 mH
0,36 Ohm EUR 8,30 excl. VAT: € 6.97 / $ 7.74
Coils
up to 25 Watt
H100
15 mH
0,83 Ohm EUR 29,05 excl. VAT: € 24.41 / $ 27.10
H100
10 mH
0,64 Ohm EUR 27,15 excl. VAT: € 22.82 / $ 25.32
H100
6,8 mH
0,46 Ohm EUR 16,20 excl. VAT: € 13.61 / $ 15.11
H71
4,7 mH
0,46 Ohm EUR 13,50 excl. VAT: € 11.34 / $ 12.59
H100
3,3 mH
0,27 Ohm EUR 14,30 excl. VAT: € 12.02 / $ 13.34
L100
2,2 mH
0,83 Ohm EUR 14,35 excl. VAT: € 12.06 / $ 13.39
L100
1,5 mH
0,62 Ohm EUR 11,45 excl. VAT: € 9.62 / $ 10.68
L100
1,00 mH
0,49 Ohm EUR 9,70 excl. VAT: € 8.15 / $ 9.05
L100
0,82 mH
0,44 Ohm EUR 9,20 excl. VAT: € 7.73 / $ 8.58
L100
0,56 mH
0,36 Ohm EUR 8,30 excl. VAT: € 6.97 / $ 7.74
Coils
up to 50 Watt
BS125
15 mH
0,59 Ohm EUR 48,35 excl. VAT: € 40.63 / $ 45.10
BS125
10 mH
0,46 Ohm EUR 43,55 excl. VAT: € 36.60 / $ 40.62
BS125
6,8 mH
0,37 Ohm EUR 40,70 excl. VAT: € 34.20 / $ 37.96
BS125
4,7 mH
0,30 Ohm EUR 38,70 excl. VAT: € 32.52 / $ 36.10
H100
3,3 mH
0,27 Ohm EUR 14,30 excl. VAT: € 12.02 / $ 13.34
H100
2,2 mH
0,21 Ohm EUR 14,00 excl. VAT: € 11.76 / $ 13.06
H100
1,5 mH
0,17 Ohm EUR 13,40 excl. VAT: € 11.26 / $ 12.50
L140
1,00 mH
0,30 Ohm EUR 17,30 excl. VAT: € 14.54 / $ 16.14
L140
0,82 mH
0,26 Ohm EUR 15,35 excl. VAT: € 12.90 / $ 14.32
L140
0,56 mH
0,2 Ohm EUR 13,45 excl. VAT: € 11.30 / $ 12.55
Coils
up to 90 Watt
PA-Trafo
mo-123200
0,12 Ohm EUR 74,44 excl. VAT: € 62.55 / $ 69.44
PA-Trafo
mo-125490
0,19 Ohm EUR 26,80 excl. VAT: € 22.52 / $ 25.00
PA-Trafo
mo-125470
0,16 Ohm EUR 25,58 excl. VAT: € 21.50 / $ 23.86
H140
4,7 mH
0,26 Ohm EUR 31,05 excl. VAT: € 26.09 / $ 28.96
H140
3,3 mH
0,19 Ohm EUR 29,15 excl. VAT: € 24.50 / $ 27.19
H140
2,2 mH
0,14 Ohm EUR 17,30 excl. VAT: € 14.54 / $ 16.14
H140
1,5 mH
0,11 Ohm EUR 15,30 excl. VAT: € 12.86 / $ 14.27
L140
1,00 mH
0,30 Ohm EUR 17,30 excl. VAT: € 14.54 / $ 16.14
L140
0,82 mH
0,26 Ohm EUR 15,35 excl. VAT: € 12.90 / $ 14.32
L140
0,56 mH
0,2 Ohm EUR 13,45 excl. VAT: € 11.30 / $ 12.55
Coils
up to 165 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 74,44 excl. VAT: € 62.55 / $ 69.44
PA-Trafo
mo-125490
0,19Ohm EUR 26,80 excl. VAT: € 22.52 / $ 25.00
PA-Trafo
mo-125470
0,16Ohm EUR 25,58 excl. VAT: € 21.50 / $ 23.86
PA-Trafo
mo-125450
0,14Ohm EUR 22,90 excl. VAT: € 19.24 / $ 21.36
BT140
3,3 mH
0,22 Ohm EUR 77,60 excl. VAT: € 65.21 / $ 72.38
BS140
2,2 mH
0,16 Ohm EUR 34,80 excl. VAT: € 29.24 / $ 32.46
BS140
3,3 mH
0,12 Ohm EUR 31,90 excl. VAT: € 26.81 / $ 29.76
H140
1,0 mH
0,08Ohm EUR 14,40 excl. VAT: € 12.10 / $ 13.43
L200
0,82 mH
0,16 Ohm EUR 33,85 excl. VAT: € 28.45 / $ 31.57
L200
0,56 mH
0,11 Ohm EUR 28,05 excl. VAT: € 23.57 / $ 26.16
Coils
up to 275 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 74,44 excl. VAT: € 62.55 / $ 69.44
T250
10 mH
0,16 Ohm EUR 199,00 excl. VAT: € 167.23 / $ 185.62
T250
6,8 mH
0,12 Ohm EUR 189,00 excl. VAT: € 158.82 / $ 176.29
T250
4,7 mH
0,08 Ohm EUR 175,00 excl. VAT: € 147.06 / $ 163.24
T200
3,3 mH
0,10 Ohm EUR 106,00 excl. VAT: € 89.08 / $ 98.87
BT140
2,2 mH
0,12 Ohm EUR 71,70 excl. VAT: € 60.25 / $ 66.88
BT140
1,5 mH
0,09 Ohm EUR 57,60 excl. VAT: € 48.40 / $ 53.73
L200
1,0 mH
0,18 Ohm EUR 36,75 excl. VAT: € 30.88 / $ 34.28
L200
0,82 mH
0,16 Ohm EUR 33,85 excl. VAT: € 28.45 / $ 31.57
L200
0,56 mH
0,11 Ohm EUR 28,05 excl. VAT: € 23.57 / $ 26.16
Coils
up to 500 Watt
T250
15 mH
0,17 Ohm EUR 242,00 excl. VAT: € 203.36 / $ 225.73
T250
10 mH
0,16 Ohm EUR 199,00 excl. VAT: € 167.23 / $ 185.62
T250
6,8 mH
0,12 Ohm EUR 189,00 excl. VAT: € 158.82 / $ 176.29
T250
4,7 mH
0,08 Ohm EUR 175,00 excl. VAT: € 147.06 / $ 163.24
T200
3,3 mH
0,10 Ohm EUR 106,00 excl. VAT: € 89.08 / $ 98.87
T200
2,2 mH
0,09 Ohm EUR 90,90 excl. VAT: € 76.39 / $ 84.79
T200
1,5 mH
0,09 Ohm EUR 77,90 excl. VAT: € 65.46 / $ 72.66
L250
1,0 mH
0,12 Ohm EUR 67,90 excl. VAT: € 57.06 / $ 63.34
L250
0,82 mH
0,10 Ohm EUR 62,90 excl. VAT: € 52.86 / $ 58.67
L250
0,56 mH
0,08 Ohm EUR 53,45 excl. VAT: € 44.92 / $ 49.86

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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