Improving the Intelligibility of Helium-Speech Produced in 13.13 Times Normal Atmospheric Pressures

摘要

The study reports the results of efforts to improve the intelligibility of helium-speech when spoken at a simulated depth of 400 feet. These efforts included the taping of helium-speech and playing it back to listeners at half speed, also passing it through an equipment system ('Varivox') which shifted frequencies downward by a factor of two while preserving real time. Higher intelligibility was obtained by employing a high-fidelity microphone and recording system. The intelligibility of this recording was greatly increased when the playback was slowed to one half speed. And a significant further increase in intelligibility was found when frequencies were shifted downward by the techniques inherent in the special equipment described. (Author)