BS EN ISO 8253-2:2009 Acoustics. Audiometric test methods. Sound field audiometry with pure-tone and narrow-band test signals
BS EN ISO 8253-2 specifies relevant test signal characteristics, requirements for free, diffuse, and quasi-free sound fields, and procedures for sound field audiometry using pure tones, frequency-modulated tones or other narrow-band test signals presented by means of one or more loudspeakers. The primary purpose is the determination of hearing threshold levels in the frequency range 125 Hz to 8 000 Hz, but this range can be extended to 20 Hz to 16 000 Hz.
BS EN ISO 8253-2 does not include specifications for the use of hand-held loudspeakers. Speech as a test signal is not covered.
BS EN ISO 8253-2 is to ensure that tests of hearing, using sound field audiometry, give a high a degree of accuracy and reproducibility as possible.
Examples of graphical representations of the results are given in Annex A.
Contents of BS EN ISO 8253-2:
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Test signal characteristics
4.1 General
4.2 Pure tones
4.3 FM tones
4.4 Narrow bands of noise4.
4.5 Harmonic distortion
4.6 Signal gating
4.7 Signal level control
4.8 Means and scales for calibration
5 Sound field characteristics
5.1 General
5.2 Free sound field
5.3 Diffuse sound field
5.4 Quasi-free sound field
6 Ambient noise levels in the test room
7 Preparation and instruction of test subject
8 Determination of hearing threshold level
8.1 General
8.2 Monaural testing
8.3 Binaural testing
9 Testing with a hearing aid
10 Screening audiometry
11 Reporting of data
11.1 General
11.2 Equipment calibrated by hearing level
11.3 Equipment calibrated by sound pressure level
12 Maintenance and calibration of equipment
12.1 General
12.2 Intervals between tests
12.3 Stage A: routine examination and listening tests
12.4 Stage B: periodic electroacoustic tests
12.5 Stage C: basic calibration tests
Annex A (informative) Graphical display of results
Annex B (informative) Correction values for 45° and 90° angles of incidence
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