What crossover frequency should I use?

It depends on the drivers. Typical values: woofer to midrange 300-800 Hz, midrange to tweeter 2-5 kHz. The crossover point should be where both drivers operate comfortably — well within their usable frequency range, not at their limits.

How many components does each crossover order need?

Per driver leg: 1st order uses 1 component (one capacitor on the high-pass leg, one inductor on the low-pass leg). 2nd order uses 2 components per leg, 3rd order uses 3, and 4th order uses 4. So a 2-way 4th-order Linkwitz-Riley network has 8 components in total. Higher orders give steeper slopes (better driver protection) but cost more and have more complex phase behaviour.

Why is a 4th-order Linkwitz-Riley network popular?

A 4th-order Linkwitz-Riley (LR4) crossover is two cascaded 2nd-order Butterworth sections ("Butterworth squared"). At the crossover point both drivers are 6 dB down and in phase, so the acoustic outputs sum flat with no peak. The steep 24 dB/octave slope also gives excellent tweeter protection. This is why LR4 is the de-facto standard for studio monitors and PA crossovers.

Why does impedance matter for crossover design?

Crossover component values are calculated from the nominal impedance of the driver. Real driver impedance varies with frequency (it rises at resonance and at high frequency due to voice-coil inductance), so the actual crossover point shifts away from the nominal calculation. Serious passive designs use impedance-compensation (Zobel) networks and measured impedance curves rather than the nominal figure alone — treat these results as a starting point.

Are active crossovers better than passive?

Active crossovers (before amplification) offer more precise control, adjustable slopes and frequencies, no power loss, and better driver protection. Passive crossovers are simpler (no extra amplifiers needed) and are standard in most consumer and many PA speakers.

AudioCalcs

Crossover Calculator — Passive Speaker Crossover Design

Calculate crossover component values for passive speaker crossover networks.

Crossover Frequency

Desired crossover point in Hz

Speaker Impedance

Nominal driver impedance, typically 4 or 8 ohms

Crossover OrderHigher orders give steeper rolloff but use more components per leg

How We Calculate This

These formulas size the components from the nominal driver impedance Z (Ω) and the crossover frequency f (Hz), treating the driver as a pure resistor. Capacitors come out in microfarads (µF) and inductors in millihenries (mH). The number of components per driver leg equals the filter order: 1st order = 1, 2nd = 2, 3rd = 3, 4th = 4.

1st Order Butterworth (6 dB/oct)

High-pass series capacitor: C = 1 / (2πfZ)

Low-pass series inductor: L = Z / (2πf)

2nd Order Butterworth (12 dB/oct)

C = √2 / (4πfZ) = 0.1125 / (fZ)

L = √2·Z / (2πf) = 0.2251·Z / f

3rd Order Butterworth (18 dB/oct)

High-pass: C1 = 0.1061/(fZ), C2 = 0.3183/(fZ), L1 = 0.1194·Z/f

Low-pass: L1 = 0.2387·Z/f, L2 = 0.0796·Z/f, C1 = 0.2122/(fZ)

4th Order Linkwitz-Riley (24 dB/oct)

High-pass: C1 = 0.0844/(fZ), C2 = 0.1688/(fZ), L1 = 0.1000·Z/f, L2 = 0.4502·Z/f

Low-pass: L1 = 0.3001·Z/f, L2 = 0.1501·Z/f, C1 = 0.2532/(fZ), C2 = 0.0563/(fZ)

Frequently Asked Questions

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Last updated: June 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.