High Speed Vessel Medical Limited Objective Experiment, Noise Assessment and Noise Reducing Stethoscope Field Test

Abstract : Throughout NSMRL's pursuit in making optimal use of auditory information in sonar displays, interference from airborne sound in the listening environment has been a major issue. NSMRL's success in using active noise cancellation to prevent masking by airborne sound has lead to the realization that shipboard spaces may be habitable by hearing-risk standards, but not operationally suitable for critical mission tasks. Digital sound processing has opened up the auditory detection, display and transmission of information in inherently noise environments. This Medical Limited Objective Experiment (LOE) was valuable both to evaluate the noise environment in spaces not designed for habitation, and to simultaneously test a pre-production noise-reducing stethoscope. In controlled setting under operationally-relevant shipboard noise conditions in the field tests, the noise-reducing stethoscope proved to be significant, substantial improvement over a conventional sound-powered device.