Accession Number : AD0682284

Title :   COMPARISON OF SPEECH RECORDINGS IN ROOM AIR AT GROUND level and in helium-OXYGEN MIXTURE AT SIMULATED ALTITUDE.

Descriptive Note : Final rept. Sep 64-May 66,

Corporate Author : SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX

Personal Author(s) : Barry,S. Joseph ; Endicott,James E.

Report Date : NOV 1968

Pagination or Media Count : 13

Abstract : Articulation functions associated with two 50-item lists of phonetically balanced speech materials of demonstrated equivalence were compared for a single male talker under two different atmospheric conditions. One set of materials was recorded in an atmosphere of ordinary room-air composition at ground level, and the other in a helium-rich atmosphere maintained at a simulated altitude of 18,000 feet. In the two sets the articulation functions resembled each other closely in slope and configuration; however, the fact that the helium-speech function was somewhat displaced along the abscissa represented an increase in sensation level. Therefore, at presentation levels below those which produce near-maximum intelligibility, the helium-speech materials required about a 6 db increase in intensity to achieve intelligibility equal to that of room-air speech. (Author)

Descriptors :   (*SPEECH, SOUND REPRODUCTION SYSTEMS), HELIUM, SPACE FLIGHT, ATMOSPHERES, DISTORTION, INTELLIGIBILITY, INTENSITY, HIGH ALTITUDE, SPEECH RECOGNITION

Subject Categories : Acoustics
      Voice Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE