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Speaker crossover (1st order) calculator

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Example Tweeter: C1 = 6.631 µF (series) — Woofer: L1 = 424.4 µH (series)

A series capacitor keeps the lows out of the tweeter; a series inductor keeps the highs out of the woofer. First order = 6 dB/octave each side, crossing at fc where each part's reactance equals the speaker impedance Z.

Tweeter: $C=\frac{1}{2\pi f_{c}Z}$ — Woofer: $L=\frac{Z}{2\pi f_c}$

For steeper 12 dB/octave (2nd-order Butterworth), use $L^{\prime }=L\times \sqrt{2}$ and $C^{\prime }=\frac{C}{\sqrt{2}}$ in an LC pair per driver — and mind the tweeter's power rating near fc.