BS EN ISO 11904-1:2002

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Measurement principle
5 Instrumentation
   5.1 Ear canal microphone
   5.2 Reference field microphone
   5.3 Check of calibration
   5.4 Filters
6 Subjects
7 Use of ear canal microphone
   7.1 Choice of ear canal measurement position
   7.2 Mounting of microphones
   7.3 Safety
8 Determination of free-field or diffuse-field
   related equivalent continuous A-weighted sound
   pressure level
   8.1 Measurement of ear canal sound pressure level
   8.2 Conversion to free-field or diffuse-field related
         sound pressure level
   8.3 A-weighting and summation
9 Free-field and diffuse-field frequency responses for
   selected ear canal measurement positions
10 Determination of free-field or diffuse-field frequency
   responses
   10.1 General
   10.2 Measurement principle
   10.3 Establishment of a free reference sound field
   10.4 Establishment of a quasi-free reference sound
         field
   10.5 Establishment of a diffuse reference sound field
   10.6 Measurement of the reference sound field
   10.7 Measurement of ear canal sound pressure level in
         reference sound field
   10.8 Determination of free-field or diffuse-field
         frequency response
   10.9 Simplifications in specific cases
   10.10 Optional check of the measurement arrangement
11 Test report
Annex A (informative) Example of sources of measurement
        uncertainty
Annex B (informative) Example of an uncertainty analysis
Bibliography

Gives basic framework measurement methods for sound immission from sound sources placed close to the ear. These measurements are carried out with miniature or probe microphones inserted in the ear canals of human subjects.

This part of ISO 11904 specifies basic framework measurement methods for sound immission from sound sources placed close to the ear. These measurements are carried out with miniature or probe microphones inserted in the ear canals of human subjects. The measured values are subsequently converted into corresponding free-field or diffuse-field levels. The results are given as free-field related or diffuse-field related equivalent continuous A-weighted sound pressure levels. The technique is denoted the microphone-in-real-ear technique (MIRE technique).

This part of ISO 11904 is applicable to exposure from sources close to the ear, for example during equipment tests or at the workplace by earphones or hearing protectors with audio communication facilities.

This part of ISO 11904 is applicable in the frequency range from 20 Hz to 16 000 Hz.