Historical
ANSI S3.4-2005
American National Standard Procedure for the Computation of Loudness of Steady Sound
This standard specifies a procedure for calculating the loudness of steady sounds as perceived by listeners with normal hearing. The procedure is based on the spectra of the sounds. The possible sounds include simple and complex tones (both harmonic and inharmonic) and bands of noise. The standard is applicable to sounds presented in free field with frontal incidence, in a diffuse field, or via headphones. A computer program, which performs the computation and provides a loudness estimate in sones, and the corresponding loudness level in phons, is provided. Use of this software is not required for conformance.
Content Provider
Acoustical Society of America [asa]