Crossover Calculator

Calculate low-pass and high-pass inductance and capacitance values based on speaker impedance, crossover frequency, and filter response. Crossover Calculator helps audio engineers, speaker designers, and enthusiasts build accurate passive crossover networks.

Highlights

  • Design passive audio crossover networks with ease.
  • Calculate inductor and capacitor values for low-pass and high-pass filters.
  • Supports speaker impedances from 1 Ω to 32 Ω.
  • Choose Butterworth, Linkwitz-Riley, or Bessel filter responses.
  • View angular crossover frequency in rad/s for accurate component sizing.

Table of Contents

  1. How Crossover Calculator Works?
  2. Practical Use Cases
  3. Accuracy and Limitations
  4. Quick Examples
  5. Frequently Asked Questions (FAQs)
  6. Cite This Calculator

How Crossover Calculator Works?

The Crossover Calculator designs a second-order passive crossover network from the speaker's nominal impedance, the selected crossover frequency, and the chosen filter response. The low-pass section sends lower frequencies to a woofer, while the high-pass section sends higher frequencies to a tweeter or other high-frequency driver.

First, the calculator determines angular crossover frequency from the selected frequency:

ωc=2πfc

For a nominal speaker impedance R, the component values are determined using response-specific normalized coefficients. The coefficients control the damping and transition shape for Butterworth, Linkwitz-Riley, or Bessel behavior.


OutputFunctionGeneral calculation
Low-pass series inductorReduces high-frequency current in the low-pass branchLLP=RkLωc
Low-pass shunt capacitorDiverts high-frequency signal away from the low-pass driverCLP=kCRωc
High-pass series capacitorBlocks lower-frequency signal from the high-pass driverCHP=kCRωc
High-pass shunt inductorProvides an alternative path for lower-frequency currentLHP=RkLωc

The calculator applies the appropriate normalized coefficient values for the selected filter response, then reports the two inductors, the two capacitors, and the angular crossover frequency. Increasing impedance generally increases the required inductor values and decreases the required capacitor values, while increasing crossover frequency reduces both types of component values.

Practical Use Cases

Audio engineers can enter a driver's nominal impedance and target crossover frequency to obtain starting values for a passive two-way speaker network. Selecting Butterworth, Linkwitz-Riley, or Bessel allows the design to match the intended transition and damping characteristics.

Speaker designers can use the low-pass series inductor and shunt capacitor values for the woofer branch and the high-pass series capacitor and shunt inductor values for the tweeter branch when developing a passive crossover prototype.

DIY audio enthusiasts can use the calculator to estimate practical component sizes for custom speaker builds, replacement crossovers, or modifications involving nominal impedances from 1 to 32 Ω and crossover frequencies from 20 to 30,000 Hz.

Electronics students and educators can compare how impedance, crossover frequency, and filter response affect passive network values while studying second-order frequency-selective circuits.

Accuracy and Limitations

The calculator provides ideal second-order passive-network values based on nominal, purely resistive speaker impedance and the selected Butterworth, Linkwitz-Riley, or Bessel response. Actual drivers have frequency-dependent impedance, acoustic roll-off, sensitivity differences, phase offsets, voice-coil resistance, inductor resistance, capacitor ESR, and component tolerances, so the calculated values are design starting points rather than guaranteed final crossover values. The inputs are limited to speaker impedance from 1 to 32 Ω and crossover frequency from 20 to 30,000 Hz; a measured impedance curve and acoustic response simulation are required for precise real-world integration.

Quick Examples

Example #1: Standard Two-Way Speaker

Example inputs for designing a passive crossover for a typical 8-ohm two-way speaker system.

Example #2: Low-Impedance Audio Crossover

Example inputs for a 4-ohm speaker system using a Linkwitz-Riley response for smooth driver integration.

Example #3: High-Frequency Driver Crossover

Example inputs for designing a higher-frequency crossover for a 16-ohm speaker using a Bessel filter response.

Frequently Asked Questions

It sets the transition point where low-frequency and high-frequency drivers begin handing off audio to each other. Choosing it appropriately helps each driver operate within its intended frequency range.

Speaker impedance affects the inductance and capacitance values needed for a desired crossover response. Use the driver’s nominal impedance as a starting point, while remembering that actual impedance varies with frequency.

Butterworth responses provide a flat passband, Linkwitz-Riley responses are commonly used for smooth acoustic summation, and Bessel responses emphasize gentle phase behavior and good transient characteristics.

A low-pass section allows lower frequencies to reach a woofer or other low-frequency driver while reducing higher-frequency content. It commonly uses a series inductor and a shunt capacitor.

A high-pass section allows higher frequencies to reach a tweeter or other high-frequency driver while reducing low-frequency content. It commonly uses a series capacitor and a shunt inductor.

Cite This Calculator