Abstract:
There have been a number of papers in underwater sound propagation for a diver's mutual communication. A healthy man's monosyllable hearing test underwater has been reported previously. Now, a report of results on disabled (hard of hearing) listeners test is given. Sound propagation tests used a standard Japanese 25 m(L)x13 m(W)x1.5 m(D) waterpool. An underwater speaker Altec type UW-30 is used and is driven by a 10-W amplifier. A listener's monosyllable test signal is used with a standard voice number (101) by an NHK announcer. The distances between the radiation speaker and the disabled listener are agreed upon at 5, 10, and 20 m, and depths are changed from 1.3 to ~1.5 m. Radiator and listener's depths are held at the same level through every test. Depth simulation used with the air chamber at 10 kg/cm[sup 2] normal air at Saitama Medical Univ., where pressures are controlled equivalent to 0-, 10-, 20-, and 30-m water depths. In the results of the articulation test, about the same scores are observed between the handicapped person and the healthy listener. Especially at the distance of 10-m, a handicapped person's average score is greater than 4% compared with the healthy person's score. Such a result requires further examinations.