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.

Source Count

An integer count greater than or equal to 1.

The implemented rule is: Free-field energetic level increase in dB from N independent equal-strength incoherent sources.^[1]

Increase Decibels

The calculated increase decibels, expressed in dB.

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.

• Calibration Level Offset

  Signed level calibration offset to add to measured readings to match a reference calibrator.

• Db Addition Two Sources

  Energetic sum of two uncorrelated sound levels in decibels.

• Db Mean Of Readings

  Energetic mean, not arithmetic mean, of two equal-duration sound-level readings.