# Speaker Crossover Calculator

URL: https://speedycalculator.com/calculators/physics/crossover/
Last updated: 2026-10-30

> The speaker crossover calculator finds the capacitor and inductor values of a passive two-way loudspeaker crossover for first-order, second-order Butterworth, Linkwitz–Riley or Bessel and third-order Butterworth alignments.

## Inputs

- Filter alignment
- Tweeter impedance (Ω, kΩ, MΩ, mΩ)
- Woofer impedance (Ω, kΩ, MΩ, mΩ)
- Crossover frequency (Hz, kHz, MHz, GHz, THz, rpm)

## Results

- Tweeter capacitor C1
- Tweeter inductor L1
- Tweeter capacitor C2
- Woofer inductor L1
- Woofer capacitor C1
- Woofer inductor L2

## Formula

```
1st order: C = 0.1592/(R_t·f), L = 0.1592·R_w/f · 2nd Butterworth: C = 0.1125/(R·f), L = 0.2251·R/f
2nd Linkwitz–Riley: C = 0.0796/(R·f), L = 0.3183·R/f · 2nd Bessel: C = 0.0912/(R·f), L = 0.2756·R/f
```

## Explanation

A crossover splits the music so low notes go to the woofer and high notes to the tweeter. Higher orders give steeper slopes (6 dB/octave per order) and protect tweeters better, at the cost of more components.

### How to use the Speaker Crossover Calculator

- **Filter alignment**
- **Tweeter impedance**
- **Woofer impedance**
- **Crossover frequency**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose the alignment, enter the tweeter and woofer nominal impedances and the crossover frequency.

### Inputs explained

FieldWhat to enterFilter alignmentChoose one: 1st order (6 dB/oct), 2nd order Butterworth (12 dB/oct), 2nd order Linkwitz–Riley, 2nd order Bessel …Tweeter impedanceUnits: Ω, kΩ, MΩ, mΩWoofer impedanceUnits: Ω, kΩ, MΩ, mΩCrossover frequencyUnits: Hz, kHz, MHz, GHz, THz, rpm

### What each result means

- **Tweeter capacitor C2** = 0.3183÷([Tweeter impedance]×[Crossover frequency])
- **Woofer inductor L2** = 0.0796×[Woofer impedance]÷[Crossover frequency]

### Example values

How the main result changes when **Tweeter impedance** changes and everything else stays at the example values above:

Tweeter impedance (Ω)Tweeter capacitor C1 (µF)411.2567.585.625104.5123.75162.8125

## Worked example

Inputs — Filter alignment: 2nd order Butterworth (12 dB/oct); Tweeter impedance: 8 Ω; Woofer impedance: 8 Ω; Crossover frequency: 2,500 Hz.

Results — **Tweeter capacitor C1 = 5.625 µF**; Tweeter inductor L1 = 0.7203 mH; Woofer inductor L1 = 0.7203 mH; Woofer capacitor C1 = 5.625 µF.

## Key terms

- **Crossover**: Filter network splitting frequencies between drivers.

## FAQ

**What crossover frequency should I use?**
Typically 1.5–3.5 kHz for two-way speakers, per the drivers' specs.

**Why Linkwitz–Riley?**
Its outputs sum flat at the crossover point.

**Should I use the nominal impedance?**
It is a starting point; real drivers vary with frequency – Zobel networks help.

**Does polarity matter?**
Second-order designs usually need the tweeter wired in reverse polarity.


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)