Speaker crossover calculator
Choose filter type and crossover frequency and see woofer, tweeter and summed curves. The sum is calculated with phase; with 2nd-order filters the tweeter is inverted so that it sums flat.
Try it free in the app
Which filter type?
4th-order Linkwitz-Riley (24 dB/oct) sums flat with correct phase and separates steeply. 2nd-order Butterworth is simple and cheap but needs an inverted tweeter; 4th-order Butterworth shows +3 dB at the crossover frequency.
Component values (2nd-order Butterworth)
Low-pass: L = √2·R/(2π·f), C = 1/(√2·2π·f·R). High-pass: C = 1/(√2·2π·f·R), L = R/(√2·2π·f). This holds for ideal resistive loads – real drivers have impedance variation and inductance that the app includes when optimizing.
Frequently asked questions
Why invert the tweeter?
With 2nd-order filters, low- and high-pass differ by 180° at the crossover frequency. Inverting the tweeter makes both branches add flat again.
Linkwitz-Riley or Butterworth?
LR4 sums flat and is the usual choice for active crossovers. For passive crossovers 2nd order is popular because it needs fewer parts.
How accurate are the curves?
They show the ideal filter function without driver response and impedance. The app calculates with drivers, measurements and optimization.