Instrumentation Methods for Measuring Diving Helmet Noise

For the past few years, the U.S. Navy Experimental Diving Unit (NEDU) has devoted intense effort to the establishment of a methodology and selection of apparatus for the assessment of (1) noise inside a manned diving helmet at depth and in the water; and (2) diver auditory threshold shifts as a function of this noise exposure. A simulated helium-oxygen saturation dive to 850 feet of sea water (FSW) was conducted during the spring of 1984 in NEDU´s Ocean Simulation Facility (OSF). Follow-up dives were conducted to 1000 FSW in 1985 and the spring of 1986. The information discussed in the paper will be limited to the techniques used to obtain sound measurements in a diving helmet used on the two deep dives.