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.

Reference Hertz

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

Band Offset

A finite measured or assumed value.

The implemented rule is: Ideal third-octave-band center from a reference frequency and signed integer third-octave offset.^[1]

Center Hertz

The calculated center 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.

• Octave Band Centers

  Ideal octave-band center frequency relative to a reference frequency and signed integer band offset.

• Absorption Required For Target Rt

  Metric Sabine equivalent absorption area required for a target RT60: 0.161V/T.

• Acoustic Impedance Medium

  Characteristic specific acoustic impedance rho*c for a uniform medium.