File:Bell telephone magazine (1922) (14754375834).jpg

Identifier: belltelephonemag19amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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f the group 10-19 years of age hasa loss of 25 db at 7,040 cycles persecond, whereas half of the oldestgroup have losses of this magnitude. Age and Residence Factors Ihe age of those participating inthe hearing investigation was esti- mated by the attendant from their ap-pearance. Approximately fifty dif-ferent attendants served each weekand they were changed about once anhour. To determine the accuracy ofthe estimates, the actual ages of overtwo hundred members of the BellLaboratories staff and their families,who took the tests without identifyingthemselves, were compared with theages recorded on their cards. It wasfound that 83 per cent were not morethan three years outside of the groupto which they were assigned. Comparison of data taken at NewYork with that from San Franciscofor the age groups below 50 yearsgave no conclusive evidence of sec-tional differences in hearing. At thethree lowest frequencies the differ-ences were insignificant. The results 19^0 Testing Americas Ears 273
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30 35 40 45 50 55 < 20AGE IN YEARS GraphicPresentations 880 1760 3520 7040 FREQUENCY IN CYCLES PER SECOND Lefl: Men hear low frequencies somewhat better than women, but women hear the higherfrequencies considerably better than men. Right: Hearing acuity for all frequenciesdecreases with age and the loss is greatest at the higher frequencies, particularly for men at 3520 and 7040 cycles per secondindicate that the hearing loss of themen who took the test at San Fran-cisco was on the average about 3 dbgreater, i During one week at each fair vis-itors were asked to indicate on theircards whether they lived in the citywhere the fair was held, within com-muting distance, or beyond. The re-plies showed that about a quarter ofthem lived in the city and anotherquarter were commuters. Althoughsectional differences in hearing arenot very definitely indicated by thesetests, the differences found suggestthat a more detailed geographicalgrouping, which also considered pastplaces of residence, m

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