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

Frequency in Hz 120 180 270 400 550 800 1250 1800 2300 3100
Cap. C in uF 100 82 47 33 22 15 10 6.8 5.6 4.7
e.g. ClarityCap PWA EUR 31,20 excl. VAT: € 26.22 / $ 30.41 EUR 26,30 excl. VAT: € 22.10 / $ 25.64 EUR 16,70 excl. VAT: € 14.03 / $ 16.28 EUR 9,90 excl. VAT: € 8.32 / $ 9.65 EUR 7,60 excl. VAT: € 6.39 / $ 7.41 EUR 5,10 excl. VAT: € 4.29 / $ 4.97 EUR 4,10 excl. VAT: € 3.45 / $ 4.00 EUR 3,60 excl. VAT: € 3.03 / $ 3.51 - not available EUR 2,60 excl. VAT: € 2.18 / $ 2.53
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 25 Watt
H71
15 mH
1,2 Ohm EUR 17,50 excl. VAT: € 14.71 / $ 17.06
H71
10 mH
0,87 Ohm EUR 14,60 excl. VAT: € 12.27 / $ 14.23
H71
6,8 mH
0,70 Ohm EUR 12,40 excl. VAT: € 10.42 / $ 12.09
H71
4,7 mH
0,46 Ohm EUR 11,40 excl. VAT: € 9.58 / $ 11.11
L100
3,3 mH
1,1Ohm EUR 23,40 excl. VAT: € 19.66 / $ 22.81
L100
2,2 mH
0,83 Ohm EUR 19,50 excl. VAT: € 16.39 / $ 19.01
L100
1,5 mH
0,62 Ohm EUR 16,60 excl. VAT: € 13.95 / $ 16.18
L100
1,00 mH
0,49 Ohm EUR 14,60 excl. VAT: € 12.27 / $ 14.23
L100
0,82 mH
0,44 Ohm EUR 13,60 excl. VAT: € 11.43 / $ 13.26
L100
0,56 mH
0,36 Ohm EUR 11,70 excl. VAT: € 9.83 / $ 11.41
Coils
up to 50 Watt
H100
15 mH
0,83 Ohm EUR 29,30 excl. VAT: € 24.62 / $ 28.56
H100
10 mH
0,64 Ohm EUR 26,40 excl. VAT: € 22.18 / $ 25.73
H100
6,8 mH
0,46 Ohm EUR 21,00 excl. VAT: € 17.65 / $ 20.47
H71
4,7 mH
0,46 Ohm EUR 11,40 excl. VAT: € 9.58 / $ 11.11
H100
3,3 mH
0,27 Ohm EUR 16,20 excl. VAT: € 13.61 / $ 15.79
L100
2,2 mH
0,83 Ohm EUR 19,50 excl. VAT: € 16.39 / $ 19.01
L100
1,5 mH
0,62 Ohm EUR 16,60 excl. VAT: € 13.95 / $ 16.18
L100
1,00 mH
0,49 Ohm EUR 14,60 excl. VAT: € 12.27 / $ 14.23
L100
0,82 mH
0,44 Ohm EUR 13,60 excl. VAT: € 11.43 / $ 13.26
L100
0,56 mH
0,36 Ohm EUR 11,70 excl. VAT: € 9.83 / $ 11.41
Coils
up to 100 Watt
BS125
15 mH
0,59 Ohm EUR 53,80 excl. VAT: € 45.21 / $ 52.44
BS125
10 mH
0,46 Ohm EUR 46,90 excl. VAT: € 39.41 / $ 45.72
BS125
6,8 mH
0,37 Ohm EUR 45,00 excl. VAT: € 37.82 / $ 43.87
BS125
4,7 mH
0,30 Ohm EUR 43,00 excl. VAT: € 36.13 / $ 41.92
H100
3,3 mH
0,27 Ohm EUR 16,20 excl. VAT: € 13.61 / $ 15.79
H100
2,2 mH
0,21 Ohm EUR 14,60 excl. VAT: € 12.27 / $ 14.23
H100
1,5 mH
0,17 Ohm EUR 12,60 excl. VAT: € 10.59 / $ 12.28
L140
1,00 mH
0,30 Ohm EUR 25,40 excl. VAT: € 21.34 / $ 24.76
L140
0,82 mH
0,26 Ohm EUR 23,40 excl. VAT: € 19.66 / $ 22.81
L140
0,56 mH
0,2 Ohm EUR 19,50 excl. VAT: € 16.39 / $ 19.01
Coils
up to 180 Watt
PA-Trafo
mo-123200
0,12 Ohm EUR 84,60 excl. VAT: € 71.09 / $ 82.47
PA-Trafo
mo-125490
0,19 Ohm EUR 28,69 excl. VAT: € 24.11 / $ 27.97
PA-Trafo
mo-125470
0,16 Ohm EUR 26,40 excl. VAT: € 22.18 / $ 25.73
H140
4,7 mH
0,26 Ohm EUR 33,20 excl. VAT: € 27.90 / $ 32.36
H140
3,3 mH
0,19 Ohm EUR 29,30 excl. VAT: € 24.62 / $ 28.56
H140
2,2 mH
0,14 Ohm EUR 22,90 excl. VAT: € 19.24 / $ 22.32
H140
1,5 mH
0,11 Ohm EUR 19,10 excl. VAT: € 16.05 / $ 18.62
L140
1,00 mH
0,30 Ohm EUR 25,40 excl. VAT: € 21.34 / $ 24.76
L140
0,82 mH
0,26 Ohm EUR 23,40 excl. VAT: € 19.66 / $ 22.81
L140
0,56 mH
0,2 Ohm EUR 19,50 excl. VAT: € 16.39 / $ 19.01
Coils
up to 330 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 84,60 excl. VAT: € 71.09 / $ 82.47
PA-Trafo
mo-125490
0,19Ohm EUR 28,69 excl. VAT: € 24.11 / $ 27.97
PA-Trafo
mo-125470
0,16Ohm EUR 26,40 excl. VAT: € 22.18 / $ 25.73
PA-Trafo
mo-125450
0,14Ohm EUR 24,61 excl. VAT: € 20.68 / $ 23.99
BT140
3,3 mH
0,22 Ohm EUR 78,30 excl. VAT: € 65.80 / $ 76.33
BS140
2,2 mH
0,16 Ohm EUR 37,10 excl. VAT: € 31.18 / $ 36.16
BS140
3,3 mH
0,12 Ohm EUR 34,20 excl. VAT: € 28.74 / $ 33.34
H140
1,0 mH
0,08Ohm EUR 17,20 excl. VAT: € 14.45 / $ 16.77
L200
0,82 mH
0,16 Ohm EUR 39,10 excl. VAT: € 32.86 / $ 38.11
L200
0,56 mH
0,11 Ohm EUR 31,30 excl. VAT: € 26.30 / $ 30.51
Coils
up to 550 Watt
PA-Trafo
mo-123200
0,12Ohm EUR 84,60 excl. VAT: € 71.09 / $ 82.47
T250
10 mH
0,16 Ohm - not available (_)
T250
6,8 mH
0,12 Ohm - not available (_)
T250
4,7 mH
0,08 Ohm - not available (_)
T200
3,3 mH
0,10 Ohm EUR 106,00 excl. VAT: € 89.08 / $ 103.33
BT140
2,2 mH
0,12 Ohm EUR 72,40 excl. VAT: € 60.84 / $ 70.57
BT140
1,5 mH
0,09 Ohm EUR 58,70 excl. VAT: € 49.33 / $ 57.22
L200
1,0 mH
0,18 Ohm EUR 44,00 excl. VAT: € 36.97 / $ 42.89
L200
0,82 mH
0,16 Ohm EUR 39,10 excl. VAT: € 32.86 / $ 38.11
L200
0,56 mH
0,11 Ohm EUR 31,30 excl. VAT: € 26.30 / $ 30.51
Coils
up to 1000 Watt
T236
15 mH
0,24 Ohm EUR 209,90 excl. VAT: € 176.39 / $ 204.61
T236
10 mH
0,18 Ohm EUR 189,90 excl. VAT: € 159.58 / $ 185.11
T236
6,8 mH
0,14 Ohm EUR 179,90 excl. VAT: € 151.18 / $ 175.36
T236
4,7 mH
0,12 Ohm EUR 134,90 excl. VAT: € 113.36 / $ 131.50
T236
3,3 mH
0,10 Ohm EUR 126,90 excl. VAT: € 106.64 / $ 123.70
BT180
2,2 mH
0,11 Ohm EUR 92,90 excl. VAT: € 78.07 / $ 90.56
BT180
1,5 mH
0,09 Ohm EUR 76,90 excl. VAT: € 64.62 / $ 74.96
BT180
1,0 mH
0,08 Ohm EUR 74,90 excl. VAT: € 62.94 / $ 73.01
VT200
0,82 mH
0,06 Ohm - not available (_)
VT200
0,56 mH
0,08 Ohm - not available (_)

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.
 

Home