Intelligibility Assessment of EBS-II Diver Communications Using an Amron Communication Amplifier with Nitrox and Heliox Breathing Mediums.
NAVY EXPERIMENTAL DIVING UNIT PANAMA CITY FL
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In January and March 1997, manned dives were conducted at the Navy Experimental Diving Unit NEDU to test the intelligibility of the EBS-II communication system using a new, candidate, AMRON communication amplifier. The goal was to gather data on the round-robin intelligibility of the communication system while using nitrox and heliox breathing mediums and to use this data to support an intelligibility recommendation for the amplifier. Objective and subjective evaluation methods were used to determine intelligibility. The first dive series tested intelligibility using nitrox at 100 fsw, the other using heliox at 300 fsw. During each series, two versions of the MK-24 microphone were tested, type A and type B. The AHRON communication amplifier produced acceptable round-robin intelligibility results in the nitrox mode. Intelligibility using the type B microphone was at least as good as with the type A microphone. In the heliox mode, using the helium speech unscrambler HSU, the amplifier produced acceptable diver-to-topside and topside-to- diver intelligibility results but failed to produce acceptable diver-to-diver results. In this mode the type B microphone provided better intelligibility than the type A microphone. Based on the findings of this report, it is recommended that the AHRON Model 28252426 two-diver communications amplifier, with helium speech unscrambler HSU, be approved for use with the EBS II Divers Communications Umbilical, the MK-24 FEM Piezoelectric microphone types A and B, and the ANPQS-2A Headset.
- Anatomy and Physiology
- Command, Control and Communications Systems