DEVELOPMENT OF A NEW STANDARD LABORATORY PROTOCOL FOR ESTIMATING THE FIELD ATTENUATION OF HEARING PROTECTION DEVICES - PART III - THE VALIDITY OF USING SUBJECT-FIT DATA
Eh. Berger et al., DEVELOPMENT OF A NEW STANDARD LABORATORY PROTOCOL FOR ESTIMATING THE FIELD ATTENUATION OF HEARING PROTECTION DEVICES - PART III - THE VALIDITY OF USING SUBJECT-FIT DATA, The Journal of the Acoustical Society of America, 103(2), 1998, pp. 665-672
The mandate of ASA Working Group S12/WG11 has been to develop ''labora
tory and/or field procedure(s) that yield useful estimates of field pe
rformance'' of hearing protection devices (HPDs). A real-ear attenuati
on at threshold procedure was selected, devised, tested via an, interl
aboratory study, and incorporated into a draft standard that was appro
ved in 1997 [J. D. Royster et al., ''Development of a new standard lab
oratory protocol for estimating the field attenuation of hearing prote
ction devices. Part I. Research of Working Group 11, Accredited Standa
rds Committee S12, Noise,'' J. Acoust. Soc. Am. 99, 1506-1526 (1996);
ANSI S12.6-1997, ''American National Standard Methods for Measuring Re
al-Ear Attenuation of Hearing Protectors'' (American National Standard
s Institute, New York, 1997)]. The real-world estimation procedure uti
lizes a subject-fit methodology with Listeners who are audiometrically
proficient, but inexperienced in the use of HPDs. A key factor in the
decision to utilize the subject-fit method was an evaluation of the r
epresentativeness of the laboratory data vis-a-vis attenuation values
achieved by workers in practice, Twenty-two field studies were reviewe
d to develop a data base for comparison purposes, Results indicated th
at laboratory subject-fit attenuation values were typically equivalent
to or greater than the field attenuation values, and yielded a better
estimate of those values than did experimenter-fit or experimenter-su
pervised fit types of results. Recent data which are discussed in the
paper, but which were not available at the time of the original analys
es, confirm the findings. (C) 1998 Acoustical Society of America. [S00
01-4966(98)03001-X].