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
Multiple driver 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:

  • up to 100 Watt: 35 Volt
  • up to 200 Watt: 50 Volt
  • up to 400 Watt: 70 Volt
  • up to 800 Watt: 100 Volt

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

  • The saturation, if it's not an air core coil (core coils lose their characteristics when overdriven),
  • the maximum power handling (possibly causing overheating!)
  • the coil's inner resistance which shouldn't be too high. A coil with a too high value and mounted in parallel to the bass drivers causes the driver's magnet to weaken, resulting in a loose and boomy bass.

    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(price: 17 .. 29 ... 60 EUR)
    - I-Punkt, core with silicon sheet iron , high power handling (price: 6 .. 12 EUR)
    - ferrite, low distortion - even at low volume (price: 6 .. 12 EUR)
    - ferrite, T-Core with extremely low distortion (price: 9 .. 11 EUR)
    - air, type 1 or 2 with lowest distortion (price: 2 .. 5 EUR)
    - large air core coil, type 3 or 4, with lowest distortion (price: 5 .. 18 EUR)
    The numbers behind the coil type (except TO1000) indicate the size in mm.

    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
    example MKP Q4 EUR 19,65 EUR 16,30 EUR 10,70 EUR 7,30 EUR 7,10 EUR 4,75 EUR 3,85 EUR 3,30 EUR 2,90 EUR 2,55
    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    		 HQ58/46
    I-279
    0.57Ohm EUR 16,40     		HQ43/45
    I-198
    0.93Ohm EUR 9,70     		HQ43/45
    I-195
    0.59Ohm EUR 9,60     		HQ43/45
    I-191
    0.46Ohm EUR 8,90     		HQ43/45
    I-187
    0.36Ohm EUR 8,50     		LU55/30
    I-34
    0.89Ohm EUR 7,20     		LU55/30
    I-30
    0.73Ohm EUR 6,50     		LU55/30
    I-26
    0.60Ohm EUR 5,70     		LU55/30
    I-24
    0.52Ohm EUR 5,40     		LU32/26
    I-246
    0.65Ohm EUR 2,50
    Coils
    up to 50 Watt    		 HQ58/46
    I-279
    0.57Ohm EUR 16,40     		HQ43/45
    I-198
    0.93Ohm EUR 9,70     		HQ43/45
    I-195
    0.59Ohm EUR 9,60     		HQ43/45
    I-191
    0.46Ohm EUR 8,90     		HQ43/45
    I-187
    0.36Ohm EUR 8,50     		LU55/30
    I-34
    0.89Ohm EUR 7,20     		LU55/30
    I-30
    0.73Ohm EUR 6,50     		LU55/30
    I-26
    0.60Ohm EUR 5,70     		LU55/30
    I-24
    0.52Ohm EUR 5,40     		LU44/30
    I-20
    0.42Ohm EUR 4,90
    Coils
    up to 100 Watt    		 TO1000
    I-594
    0.29Ohm EUR 45,70     		i-Kern
    I-1015
    0.56Ohm EUR 18,90     		i-Kern
    I-1013
    0.44Ohm EUR 17,70     		i-Kern
    I-1007
    0.26Ohm EUR 18,20     		i-Kern
    I-1005
    0.21Ohm EUR 17,60     		LU78/30
    I-64
    0.46Ohm EUR 17,30     		LU62/41
    I-62
    0.34Ohm EUR 14,20     		LU62/41
    I-60
    0.28Ohm EUR 11,20     		LU62/41
    I-57
    0.26Ohm EUR 11,00     		LU62/41
    I-55
    0.22Ohm EUR 9,90
    Coils
    up to 180 Watt    		 PA-Trafo
    mo-123200
    0.12Ohm EUR 80,90     		PA-Trafo
    mo-125490
    0.19Ohm EUR 21,45     		i-Kern
    I-1013
    0.44Ohm EUR 17,70     		i-Kern
    I-1007
    0.26Ohm EUR 18,20     		i-Kern
    I-1005
    0.21Ohm EUR 17,60     		i-Kern
    I-1003
    0.17Ohm EUR 17,30     		i-Kern
    I-1001
    0.14Ohm EUR 16,90     		LU62/41
    I-60
    0.28Ohm EUR 11,20     		LU62/41
    I-57
    0.26Ohm EUR 11,00     		LU62/41
    I-55
    0.22Ohm EUR 9,90
    Coils
    up to 330 Watt    		 PA-Trafo
    mo-123200
    0.12Ohm EUR 80,90     		PA-Trafo
    mo-125490
    0.19Ohm EUR 21,45     		PA-Trafo
    mo-125470
    0.16Ohm EUR 18,80     		PA-Trafo
    mo-125450
    0.14Ohm EUR 17,40     		i-Kern
    I-1005
    0.21Ohm EUR 17,60     		i-Kern
    I-1003
    0.17Ohm EUR 17,30     		i-Kern
    I-1001
    0.14Ohm EUR 16,90     		LU92/39
    I-924
    0.17Ohm EUR 17,30     		LU92/39
    I-922
    0.15Ohm EUR 16,10     		LU92/39
    I-918
    0.12Ohm EUR 13,80
    Coils
    up to 550 Watt    		 PA-Trafo
    mo-123200
    0.12Ohm EUR 80,90     		FE130
    I-770
    0.17Ohm EUR 149,90     		FE130
    I-750
    0.12Ohm EUR 128,70     		FE130
    I-720
    0.08Ohm EUR 94,60     		FE130
    I-700
    0.06Ohm EUR 89,40     		FE96
    I-330
    0.10Ohm EUR 69,10     		FE96
    I-310
    0.08Ohm EUR 55,00     		LU92/39
    I-924
    0.17Ohm EUR 17,30     		LU92/39
    I-922
    0.15Ohm EUR 16,10     		LU92/39
    I-918
    0.12Ohm EUR 13,80
    Coils
    up to 1000 Watt    		 upon request FE130
    I-770
    0.17Ohm EUR 149,90     		FE130
    I-750
    0.12Ohm EUR 128,70     		FE130
    I-720
    0.08Ohm EUR 94,60     		FE130
    I-700
    0.06Ohm EUR 89,40     		FE96
    I-330
    0.10Ohm EUR 69,10     		FE96
    I-310
    0.08Ohm EUR 55,00     		upon request upon request upon request

    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 EX2 MAG-crossover.
     

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