ISO 11904-2-2021 pdf free download – Acoustics — Determination of sound immission from sound sources placed close to the ear — Technique using a manikin.
This document specifies basic framework measurement methods for sound immission from soundsources placed close to the ear. These measurements are carried out with a manikin， equippedwith ear simulators including microphones. The measured values are subsequently converted intocorresponding 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 themanikin technique.
This document is applicable to exposure to sound from sources close to the ear, for example duringequipment tests or at the workplace to sound from earphones or hearing protectors with audiocommunication facilities.
This document is applicable in the frequency range from 20 Hz to 10 kHz.For frequencies above 10 kHz,ISO 11904-1 can be used.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references,only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.IEC 61260,Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1,Electroacoustics — Sound level meters — Part 1: SpecificationsITU-TP.58:2013,Head and torso simulator for telephonometry
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IlEC maintain terminological databases for use in standardization at the following addresses:- ISO online browsing platform: available at https:.//www.iso.org/obp
—IEC Electropedia: available at http://www.electropedia.org/
3.1
manikin sound pressure levelLM,expof,
equivalent continuous sound pressure level in one-third-octave frequency bands with nominalmidband frequency f, measured with the microphone of an ear simulator integrated in a manikin whenthe manikin is exposed to the sound under test
3.2
free-field frequency response for use with manikinsLFF,M,f .
EAsnission oF 2H2AaaRm0i r l .……mpp..
ear simulator in tabulated values of ALFF.M.f
Note 2 to entry:The free-field frequency response for use with manikins is identical to the amplitude of the head-related transfer function (HRTF) for frontal sound incidence.
Note 3 to entry: The human free-field frequency response is defined in ISo 11904-1.3.3
diffuse-field frequency response for use with manikinsLDF,M,f ,
average human diffuse-field frequency response for use with manikins, corrected for the differencebetween the sound transmission inside the average human ear canal and the correspondingtransmission of the manikin ear simulator
Note 1 to entry: For applicability with manikins, the eardrum reference is replaced by the output of the manikinear simulator in tabulated values of ALDF,M,f
Note 2 to entry: The human diffuse-field frequency response is defined in IS0 11904-1.3.4
free-field related sound pressure level determined with a manikinLFE,M..
free-field sound pressure level determined with the method using a manikin
Note 1 to entry:The definition may be applied to specific frequencies or frequency bands, weighted or unweightedlevels, specific time weightings, etc., for instance “free-field related equivalent continuous A-weighted soundpressure level” (free-field related LM,Aeqalso denoted LFF,M,AeqJ.
Note 2 to entry:The method is aimed at the mean free-field related sound pressure level that would be obtainedwith a large human population.
Note 3 to entry:The free-field related sound pressure level for a human subject is defined in IS0 11904-1.3.5
diffuse-field related sound pressure level determined with a manikinLDE,M
diffuse-field sound pressure level determined with the method using a manikin
Note 1 to entry:The definition may be applied to specific frequencies or frequency bands, weighted or unweightedlevels, specific time weightings,etc..for instance “diffuse-field related equivalent continuous A-weighted soundpressure level” (diffuse-field related LM,Aeq also denoted LDF,M,Aeq)-
Note 2 to entry: The method is aimed at the mean diffuse-field related sound pressure level that would beobtained with a large human population.
Note 3 to entry: The diffuse-field related sound pressure level for a human subject is defined in ISo 11904-1.ISO 11904-2 pdf download.