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.

Mode Order

An integer count greater than or equal to 1.

Room Length Meters

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

The implemented rule is: Rectangular-room axial mode frequency along one dimension for a positive integer mode order.^[1]

Mode Hertz

The calculated mode 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.

• Oblique Mode Frequency

  Rectangular-room mode frequency for three nonzero axial orders and dimensions.

• Tangential Mode Frequency

  Rectangular-room mode frequency for two nonzero axial mode orders and dimensions.

• Schroeder Frequency

  Approximate Schroeder transition frequency 2000 sqrt(RT60/V) for room volume in m³ and reverberation time in seconds.