ASA S3.4-1980 (R2003)

This standard specifies a procedure for calculating the loudness experienced by a typical listener under the following conditions:

Diffuse Field or Free Field. The listener may be in either a diffuse sound field or a free sound field. In a diffuse field, it is asumed that sound reaches the listener’s ears from essentially all directions. In a free field, the sound source is assumed to be located at least one meter directly in front of the listener (frontal incidence). The sound field in an acoustically hard room where the sound is reflected many times before being significantly absorbed approximates a diffuse field. The sound field in an anechoic chamber or outdoors in a relatively obstruction-free environment approximates a free field.

Reaffirmed 19 November 2003.

Published:

01/01/1980

ANSI:

ANSI Approved

Number of Pages:

13