Calculate audio crossover network component values for Butterworth and Linkwitz-Riley filters with 1st through 4th order designs.
A passive crossover splits audio into frequency bands so each driver handles the range it was built for. In a 2-way or 3-way speaker, that usually means keeping low frequencies away from the tweeter and steering upper mids and highs away from the woofer.
This calculator works out the capacitor and inductor values for common passive crossover topologies, including Butterworth and Linkwitz-Riley designs from 1st through 4th order. Enter the target crossover frequency, speaker impedance, and filter order to see the component values for the high-pass and low-pass sections.
It is useful when you are designing a custom speaker, checking a car audio crossover, or comparing how steeper filter orders affect phase and driver protection. The result changes with impedance, frequency, and order, so the calculator makes those tradeoffs visible without manual filter math.
Use this calculator when you need component values for a speaker network and want to compare filter orders before buying parts. It is especially helpful for custom builds, speaker upgrades, and crossover experiments where impedance and cutoff frequency both matter.
Butterworth 2nd-order crossover: High-pass capacitor: C = 1 / (ω × Z × √2) High-pass inductor: L = (Z × √2) / ω Low-pass inductor: L = Z / (ω × √2) Low-pass capacitor: C = √2 / (ω × Z) Where ω = 2π × f (crossover frequency) and Z = speaker impedance.
Result: HP Capacitor: 5.63 µF, LP Inductor: 0.72 mH
A 2nd-order Butterworth crossover at 2500 Hz with 8Ω speakers requires a 5.63 µF capacitor in series for the high-pass and a 0.72 mH inductor in series for the low-pass section.
Match the calculated parts to the exact driver impedance you plan to use, then compare the resulting rolloff and phase behavior against the rest of the system.
A crossover often looks correct on paper but fails in practice when the driver impedance is only approximate, the capacitor value is rounded too aggressively, or the chosen order creates an awkward acoustic overlap.
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The crossover frequency depends on your drivers. A typical 2-way bookshelf uses 2000–3000 Hz. For subwoofer-to-main crossovers, 60–120 Hz is common. Choose a frequency where both drivers can perform well.
Butterworth filters have a -3 dB point at the crossover frequency, while Linkwitz-Riley (4th order) has a -6 dB point, resulting in flat combined response. LR crossovers have better lobing behavior.
Yes, the impedance directly affects component values. Using the wrong impedance will shift the crossover point. Use the nominal impedance (4Ω or 8Ω) of your driver.
Yes, you can combine standard capacitor values in parallel to reach the calculated value. For example, get 5.6 µF by combining a 4.7 µF and 1.0 µF cap in parallel.
1st order is simplest with best phase response but poor driver protection. 2nd order is the most popular. 4th order Linkwitz-Riley offers steep rolloff and flat summed power response.
Yes, a 1st order low-pass uses a single inductor in series, while the high-pass uses a single capacitor in series. It is the simplest crossover topology.