Car Audio - Crossover Calculators
First Order, Second, Third, Fourth, Zobel Circuit & L-pad
- Make sure you have Java turned on in your browser.
- Enter high and low pass speaker impedances.
- Enter desired crossover frequency.
- On the second-order crossover calculator you must select type of
- Click on the "calculate" button to get the answers.
- Impedance is the nominal resistance of the speaker (typically 4
- Enter frequency in Hertz (not kHz).
- Capacitor value(s) are given in millionths of a Farad (µF).
- Inductor value(s) are given in thousands of a Henry (mH).
- For the Zobel circuit, enter inductance in Henries (not mH).
- First Order Crossover (6db/octave).
- Second Order Crossover
- Third Order Crossover (18db/octave).
- Fourth Order Crossover
- Zobel Circuit (Impedance
- L-pad Circuit (Speaker Attenuation).
First Order (6db/octave) Two-Way
- Phase shift on a first-order crossover is 90 degrees.
Second Order (12db/octave) Two-Way
- Linkwitz-Riley crossovers match attenuation slopes so that
system response is flat at crossover point.
- Butterworth crossovers yield to a peak at the crossover
- Bessel crossovers have a frequency response between
Linkwitz-Riley and Butterworth crossovers.
- The phase shift on a second-order crossover is 180 degrees
Third Order (18db/octave) Two-Way
- Phase shift on a third-order crossover is 270 degrees (-90
Fourth order (24dB/octave) Two-Way
- The phase shift on a fourth-order crossover is 360 degrees =
0 degrees (no phase shift).
Zobel Circuit (Impedance
- Even though speakers are rated at a certain
"resistance" (i.e. 4 Ohms), the actual impedance varies with frequency (speakers
have inductance). To compensate for the non-linearity of speakers (on mainly subwoofers),
Zobel circuits are used.
- Re is the DC resistance of the woofer (can be measured with
- Le (or Lces) is the electrical inductive equivalent of the
L-pad (Speaker Attenuation)
- An L-pad circuit will attenuate a speaker.
- L-pads keep the load "seen" by the amplifier
constant, affecting only the power delivered to the speaker. The power delivered by
the amplifier remains constant.
- Since L-pads are made from resistors, it does not induce any
phase shifts, or affect frequency response.