Helmholtz Resonance Frequency

Use this calculation for a first-order acoustics estimate when the stated geometry, propagation model, averaging convention, reference quantity, and SI units match the measurement or design problem.

Sound Speed Meters Per Second

A finite measured or assumed value greater than or equal to 0, expressed in m/s.

Neck Area Square Meters

A finite measured or assumed value greater than or equal to 0, expressed in m2.

Cavity Cubic Meters

A finite measured or assumed value greater than or equal to 0, expressed in m3.

Effective Neck Meters

A finite measured or assumed value greater than or equal to 0, expressed in m.

The implemented rule is: Lumped Helmholtz resonator frequency from sound speed, neck area, cavity volume and effective neck length.

Frequency Hertz

The calculated frequency hertz, expressed in Hz.

This is an idealized calculation rather than a complete acoustic simulation or measurement. Reflections, boundary conditions, directivity, damping, frequency dependence, near-field behavior, background noise, transducer response, temperature, humidity, and geometry can change a real result.

Confirm important results with calibrated measurements or a model that includes the actual geometry, materials, boundaries, source directivity, and frequency-dependent losses. Preserve the reference quantity and weighting whenever a result is expressed in decibels.

• Helmholtz Port Length

  Physical Helmholtz neck length required for a target resonance, subtracting a supplied total end correction.

• Pipe End Correction

  Approximate unflanged open-pipe end correction 0.61 times the pipe radius, per open end.