COMPARISON OF SEVEN SYSTEMS FOR AIR CONDUCTION AUDIOMETRY FROM 8-20 KC/S
NAVAL SUBMARINE MEDICAL RESEARCH LAB GROTON CT
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Seven equipment systems were assembled to study human auditory acuity from 8-20 kilocyclessec. Twenty-eight ears were examined. Two loudspeakers and two earphones were utilized, two types of stimulus pure tones and narrow bands of noise, and two psychometric methods Limits and Adjustments. All systems were capable of providing usably reliable thresholds throughout the whole frequency range. When objectively calibrated, several systems those involving loudspeakers, as well as those involving earphones, yielded quite comparable reference threshold sound pressure levels as inferred at the eardrum. A slight preference was expressed for a system, the method of using Bekesy threshold-tracking, with a changing-frequency noise band 300 cs in width, and for a discrete-tone system which uses the Method of Constants.
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