Helmholtz Resonator Calculator

Created by Luciano Mino
Last updated: Nov 05, 2022

The Helmholtz resonator calculator can easily find the resonant frequency for any given cavity just from its volume and aperture's dimensions.

Keep reading while we explain everything you need to know about Helmholtz resonators!

With this short text, you will learn:

• What a Helmholtz resonator is;
• The Helmholtz frequency and Helmholtz resonance definitions;
• Helmholtz resonators applications; and
• More!

What is a Helmholtz resonator?

A Helmholtz resonator is a type of sound chamber that is used to create specific tones and frequencies. This type of resonator typically consists of a tube or cavity with the open end facing into a larger space, such as an air duct or another noise-generating environment.

The frequency at which the Helmholtz resonator will resonate or vibrate is the Helmholtz frequency. We describe this frequency using the Helmholtz frequency formula.

Note: The model used in this Helmholtz resonator calculator only applies where the wavelength of the sound produced by the resonator is much larger than the resonator's dimensions.

💡 Many different shapes can be treated as a resonator. Experiment with those we included in our Helmholtz resonator calculator and see how they differ from each other!

Helmholtz frequency formula

You can find the Helmholtz frequency for any resonator from its volume and aperture's length and cross-section area:

$f = \frac{c}{2\pi}\sqrt{\frac{S}{VL}}$

where:

• $c$ is the speed of sound in air ($v = 343\ \frac{\text{m}}{\text{s}}$);
• $V$ is the volume of the resonator;
• $S$, the cross-section area of the aperture; and
• $L$, the aperture's length.

You can input these parameters in many different units with our Helmholtz resonator calculator. Give it a try!

🔎 You can read more about how the speed of sound changes with temperature in our speed of sound calculator!

Helmholtz resonator exhaust

Helmholtz resonator exhaust systems are commonly used in vehicles to help reduce noise from the engine, transmission, and exhaust system. By strategically placing Helmholtz resonators at key locations along the vehicle's air ducts or exhaust pipes, it is possible to create a Helmholtz frequency that cancels out low-frequency noises generated by these systems. This can help improve overall vehicle comfort and reduce cabin noise, making for a more pleasant driving experience.

Luciano Mino
Resonator shape
Type of shape
Arbitrary shape
Volume
cu ft
Opening
Type of opening
Arbitrary shape
Area
in²
Length of the opening
in
Result
Resonance frequency
Hz
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