GB/T 4854.4-1999 English PDF (GBT4854.4-1999)

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GB/T 4854.4-1999: Acoustics. Reference zero for the calibration of audiometric equipment. Part 4: Reference levels for narrow-band masking noise
GB/T 4854.4-1999
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 17.140.01
A 42
eqv ISO 389-4:1994
Acoustics - Reference Zero for the Calibration of
Audiometric Equipment - Part 4: Reference Levels for
Narrow-band Masking Noise
ISSUED ON: MARCH 08, 1999
IMPLEMENTED ON: SEPTEMBER 01, 1999
Issued by: The State Bureau of Quality and Technical Supervision
Table of Contents
Foreword ... 3 
ISO Foreword ... 5 
Introduction ... 6 
1 Scope ... 7 
2 Normative References ... 7 
3 Definitions ... 8 
4 Specifications ... 9 
Annex A (informative) Notes on the Derivation of the Reference Levels ... 11 
Annex B (informative) Bibliography ... 13 
Foreword
This Standard equivalently adopts international standard ISO 389-4:1994 Acoustics –
Reference Zero for the Calibration of Audiometric Equipment - Part 4: Reference
Levels for Narrow-band Masking Noise.
This standard makes unified provisions for masking noise level in pure tone testing. It
will actively promote the standardization of acoustic technology, promote the acoustic
development and international exchanges.
This is the 4th standard of the standard series Acoustics - Reference Zero for the
Calibration of Audiometric Equipment. This standard series GB/T 4854 has seven
standards under the general topic Acoustics - Reference Zero for the Calibration of
Audiometric Equipment, which are:
GB/T 4854.1 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 1: Reference Equivalent Threshold Sound Pressure Levels for
Pure Tones and Supra-aural Earphones
GB/T 16402 Acoustics - Reference Equivalent Threshold Sound Pressure Levels
for Pure Tones and Insert Earphones
GB/T 4854.3 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 3: Reference Equivalent Threshold Force Levels for Pure Tones
and Bone Vibrators
GB/T 4854.4 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 4: Reference Levels for Narrow-band Masking Noise
GB/T 4854.5 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 5: Reference Equivalent Threshold Sound Pressure Levels for
Pure Tones in the Frequency Range 8 kHz to 16 kHz
GB/T 4854.6 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 6: Reference Hearing Threshold Levels for Test Signals of Short
Duration
GB/T 4854.7 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 7: Reference Threshold of Hearing under Free-field and Diffuse-
field Listening Conditions
NOTE:
1. When the Part 2 in the series was formulated, the standard series has not been formed.
When GB/T 16402 is revised, the standard number will be modified into GB/T 4854.2.
Acoustics - Reference Zero for the Calibration of
Audiometric Equipment - Part 4: Reference Levels for
Narrow-band Masking Noise
1 Scope
This Standard specifies reference levels for narrow-band masking noise presented by
air conduction from an earphone in pure-tone audiometry. The data are given in terms
of levels to be added to the reference equivalent threshold sound pressure levels for
the corresponding pure-tone frequencies as specified in GB/T 4854.1 or GB/T 16402,
respectively, when the masking earphone is placed on the appropriate acoustic coupler,
ear simulator or artificial ear.
Data are given for noise bandwidths of one-third and one-half octaves.
NOTE: some notes on the derivation of the reference levels are given in Annex A.
2 Normative References
The following standards contain provisions which, through reference in this text,
constitute provisions of this Standard. At the time of publication, the editions indicated
where valid. All standards are subject to revision, and parties to agreements based on
this Standard are encouraged to investigate the possibility of applying the most recent
editions of the standards indicated below.
GB/T 4854.1-1999 Acoustics - Reference Zero for the Calibration of Audiometric
Equipment - Part 1: Reference Equivalent Threshold Sound Pressure Levels for Pure
Tones and Supra-aural Earphones (eqv ISO 389-1:1991)
GB/T 7341.1-1998 Audiometers - Part 1: Pure-tone Audiometers (idt IEC 645-1:1992)
GB/T 7342-1987 IEC Provisional Reference Coupler for the Calibration of Earphones
Used in Audiometry (eqv IEC 303:1970)
GB/T 7614-1987 An Artificial Ear of Wide Band Type for the Calibration of Earphones
Used in Audiometry (eqv IEC 318:1970)
GB/T 16402-1996 Acoustics - Reference Equivalent Threshold Sound Pressure Levels
for Pure Tones and Insert Earphones (eqv ISO 389-2:1994)
SJ/Z 9144-1987 IEC Reference Coupler for the Measurement of Hearing Aids Using
Earphones Coupled to the Ear by Means of Ear Inserts