EN ISO 11904-2:2004

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Measurement principle
5 Instrumentation
  5.1 Manikin (head and torso simulator)
  5.2 Check of calibration
  5.3 Filters
6 Determination of free-field or diffuse-field related
  equivalent continuous A-weighted sound pressure level
  6.1 Measurement of manikin sound pressure level
  6.2 Conversion to free-field or diffuse-field related
      sound pressure level
  6.3 A-weighting and summation
7 Test report
Annex A (informative) Example of sources of measurement
                      uncertainty
Annex B (informative) Example of an uncertainty analysis
Bibliography

ISO 11904-2:2004 specifies basic framework measurement methods for sound immission from sound sources placed close to the ear. These measurements are carried out with a manikin, equipped with ear simulators including microphones. 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 manikin technique.ISO 11904-2:2004 is applicable to exposure to sound from sources close to the ear, for example during equipment tests or at the workplace to sound from earphones or hearing protectors with audiocommunication facilities.ISO 11904-2:2004 is applicable in the frequency range from 20 Hz to 10 kHz. For frequencies above 10 kHz, ISO 11904-1 can be used.