INFLUENCE OF SELECTED VIBRATIONS UPON SPEECH (RANGE OF CPS AND RANDOM)
Rept. for Nov 1961-Dec 1962
AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
Certain characteristics of speech production are altered during low- frequency vibration 2-20 cps of the talker. In view of this, speech communication is not at all assured during the vibration and buffeting associated with powered flight, launch, and reentry of manned space flights of the present and the future. Vibrations having the most adverse effects upon man are low- frequency sinusoidal, and random in nature. Standard speech material read by talkers exposed to low-frequency sinusoidal and random vibration conditions was recorded. This material was evaluated both objectively and subjectively in terms of intelligibility, duration, and quality of speech. In experiment I, seated talkers were subjected to vertical, low-frequency sinusoidal vibration. Frequencies of vibration most detrimental to speech production were 6 cps, 8 cps, and 10 cps when speech material was presented in combination with a masking noise. In experiment II, the sitting talkers were exposed to random vibration that simulated the type of conditions experienced in actual space missions and during high-speed, low-altitude flight. No significant differences in speech production were found due to random vibration 0.5 to 8 cps.