GB/T 4854.7-1999
Acoustics--Reference zero for the calibration of audiometric equipment--Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions (English Version)

Standard No.

GB/T 4854.7-1999

Language

Chinese, Available in English version

Release Date

1999

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Status

Be replaced 2009-02

Replace By

GB/T 4854.7-2008

Latest

GB/T 4854.7-2008

Scope

This standard specifies the reference hearing threshold for calibrating audiometric equipment under the following conditions of use. a) The sound field in the absence of the listener consists of a free plane traveling wave (free field) or a diffuse field. For free plane traveling waves, the sound source should be directly in front of the listener (normal incidence). Note 1: See GB/T 16403 for the correction value of the hearing threshold when the sound incidence angle selected by free-field audiometry deviates from the normal incidence. b) The acoustic signal should be a pure (sine) tone if it is a free field, or 1/3 octave band (white or pink) noise if it is a diffuse field. c) The sound pressure level should be measured at the center of the listener's head (the midpoint of the line connecting the openings of the external auditory canals of the two ears) when the listener is not present. d) Listening with both ears. e) The sound pressure level corresponding to the reference hearing threshold is determined from the median value of the threshold of a group of suitable listeners. f) The listener should be a person with normal otology, aged between 18 and 25 years old. Note 2: The hearing threshold level of the listener who derives the standard set by this standard is 10dB or less than 10dB according to GB4854.1. This selection criterion is different from that used to derive the GB4854.1 benchmark. g) To determine the hearing threshold, use the ascending and descending method or ascending method stipulated in GB/T16403.

GB/T 4854.7-1999 history

• 2008 GB/T 4854.7-2008 Acoustics.Reference zero for the calibration of audiometric equipment.Part 7:Reference threshold of hearing under free-field and diffuse-field listening conditions
• 1999 GB/T 4854.7-1999 Acoustics--Reference zero for the calibration of audiometric equipment--Part 7: Reference threshold of hearing under free-field and diffuse-field listening conditions

GB/T 4854.7-1999 -All Parts