File:Bell telephone magazine (1922) (14754372104).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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ity with age, particularly for thehigher frequencies. At the lower fre-quencies the loss is small and some-what less for men than women, but atthe higher frequencies men lose con-siderably more than women. The tests were made in sound-proofrooms, each of which accommodatedseven visitors in partially screenedsections. Seated at a table, with acard at hand on which to record theresults, the person tested held a tele-phone receiver to his ear and listenedto spoken words or tones which wererepeated, with variations—each timefainter than before. In the word test the visitor heard aseries of two-number words, such as eight five. As successive numberswere spoken, they were recorded in acolumn on the card, until they becametoo faint to be heard. When twelvepairs had been announced, the testwas repeated with a different series. Pure musical tones were used inthe other test. There were five ofthem, an octave apart, extending up-ward from 440 cycles per second— 19^0 Testing Americas Ears 267
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CHECKING THE HEARING-TEST CARDS Light passing through the card reveals all the tones which could have been heard andindicates whether the individuals hearing is normal or good, slightly impaired, or impaired which corresponds to A above middleC on the piano—to 7040 cycles persecond. Beginning with the lowest,the tones were sounded in groups offrom one to three pulses—at first loudenough to be heard easily and thenfainter and fainter, in from 6 to 10decibel steps, until only audible bythose with exceptionally acute hear-ing. The number of pulses heardeach time was recorded in a columnon the card. When the series for thelowest tone had been completed, thetone an octave higher was sounded, atfirst loud and then progressivelyfainter. The complete test showedfive rows of figures on the card, eachcorresponding to a different pitch. On the back of the card was printedin reverse the correct number ofpulses sounded. By holding the cardso that light passed through it, thesenumbers could be

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