Loudspeaker Crossover 18 dB Calculation

On this page, the coils and capacitors for a 3rd order loudspeaker crossover are calculated. The attenuation of the high and low pass is 18 dB per octave. Enter the speaker impedance and crossover frequency values. Then click calculate.

Calculate crossover  Input Delete Entries Impedance Ω Frequency Hz Decimal places 0 1 2 3 4  Low pass results Inductor L1 Inductor L2 Capacitor C1  High pass results Capacitor C2 Capacitor C3 Inductor L3

Characteristics of 3rd order crossovers

A 3rd order crossover requires 3 components in each branch. The slope is 18dB per octave. The attenuation at the crossover frequency is 3 dB.

There are different filter types and therefore different formulas for calculating the crossover. Bessel filters have good phase response and transient response, but poor ones Amplitude behavior in the takeover frequency range. Chebyshev filters provide good amplitude response, but suffer from inadequate swing-in and swing-out behavior. The most favorable compromise between these two filter types represent the Butterworth filters whose formulas are described below and which this calculator works with.

The phase rotates from 0 to 360° depending on the frequency. Both loudspeakers are polarized in the same way.