Comparison of Speech Recordings in Room Air at Ground Level and in Helium-Oxygen Mixture at Simulated Altitude

摘要

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)