Audio Crossover Frequency
f_c = 1 / (2π√(LC))
Quick answer
This calculator solves f_c = 1 / (2π√(LC)) for Crossover Frequency. With Inductance 10 mH, Capacitance 100 µF, the result is 0.1592 kHz. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Audio crossover networks split the frequency spectrum between multiple speaker drivers, directing low frequencies to woofers and high frequencies to tweeters. The crossover frequency is determined by the LC resonance point where the inductor and capacitor impedances are equal. A second-order crossover using both L and C provides a 12 dB/octave slope, which gives better driver protection and flatter frequency response than a simple first-order (6 dB/octave) filter. The component values must be calculated for the nominal impedance of the speaker drivers.
Variables
- f_c — Crossover frequency (Hz)
- L — Inductor value (H)
- C — Capacitor value (F)
Practical Notes
Common crossover points are 80-200 Hz (subwoofer/woofer), 1-3 kHz (woofer/tweeter for two-way), and 500 Hz/5 kHz (three-way systems). Use air-core inductors for tweeters to avoid saturation distortion. Film capacitors are preferred over electrolytics in crossover networks due to lower ESR and better linearity. Always verify the crossover behavior with actual impedance measurements of your drivers.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| fc | Crossover Frequency | Hz | Hz, kHz, MHz, GHz |
| L | Inductance | mH | nH, µH, mH, H |
| C | Capacitance | µF | pF, nF, µF, mF, F |
Step by step
- 1. What you know: Inductance 10 mH, Capacitance 100 µF
- 2. The relation: f_c = 1 / (2π√(LC))
- 3. Substitute: L = 10 mH, C = 100 µF
- 4. Result: Crossover Frequency = 0.1592 kHz
Worked examples
Minimum range
Given: Inductance 100 µH, Capacitance 100 nF
Result: Crossover Frequency = 50.33 kHz
Low range
Given: Inductance 1 mH, Capacitance 1 µF
Result: Crossover Frequency = 5.033 kHz
Typical
Given: Inductance 10 mH, Capacitance 100 µF
Result: Crossover Frequency = 0.1592 kHz
High range
Given: Inductance 100 mH, Capacitance 1 mF
Result: Crossover Frequency = 15.92 Hz
Maximum range
Given: Inductance 1 H, Capacitance 10 mF
Result: Crossover Frequency = 1.592 Hz
Solving for each variable
Solve for Crossover Frequency
Inductance 100 µH, Capacitance 100 nF → 50.33 kHz
Solve for Inductance
Crossover Frequency 5 Hz, Capacitance 100 nF → 10130 H
Solve for Capacitance
Crossover Frequency 5 Hz, Inductance 100 µH → 10.13 F
How Crossover Frequency changes with Inductance
| Inductance (input) | Crossover Frequency (result) |
|---|---|
| 1 mH | 0.5033 kHz |
| 2.5 mH | 0.3183 kHz |
| 5 mH | 0.2251 kHz |
| 7.5 mH | 0.1838 kHz |
| 10 mH | 0.1592 kHz |
| 15 mH | 129.9 Hz |
| 20 mH | 112.5 Hz |
| 40 mH | 79.58 Hz |
| 70 mH | 60.15 Hz |
| 100 mH | 50.33 Hz |
The same result in other units
| Unit | Value |
|---|---|
| Hz | 159.2 |
| kHz | 0.1592 |
| MHz | 0.0001592 |
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<p><a href="https://vbatpower.com/formulas/audio-crossover-lc/">Audio Crossover Frequency</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Audio Crossover Frequency?
Use f_c = 1 / (2π√(LC)). With Inductance 10 mH, Capacitance 100 µF, Crossover Frequency works out to 0.1592 kHz.
What is the formula for Audio Crossover Frequency?
The formula is f_c = 1 / (2π√(LC)). Audio crossover networks split the frequency spectrum between multiple speaker drivers, directing low frequencies to woofers and high frequencies to tweeters.
How do you find Inductance when you know the other values?
Rearrange for Inductance: with Crossover Frequency 5 Hz, Capacitance 100 nF, Inductance is 10130 H.
How do you find Capacitance when you know the other values?
Rearrange for Capacitance: with Crossover Frequency 5 Hz, Inductance 100 µH, Capacitance is 10.13 F.
What units does Audio Crossover Frequency use?
Crossover Frequency is shown in Hz, kHz, MHz. Values are held in SI base units internally, so you can mix prefixes without converting by hand.
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