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Comparison of speech intelligibility in cockpit noise using SPH-4 flight helmet with and without active noise reductionActive Noise Reduction (ANR) is a new technology which can reduce the level of aircraft cockpit noise that reaches the pilot's ear while simultaneously improving the signal to noise ratio for voice communications and other information bearing sound signals in the cockpit. A miniature, ear-cup mounted ANR system was tested to determine whether speech intelligibility is better for helicopter pilots using ANR compared to a control condition of ANR turned off. Two signal to noise ratios (S/N), representative of actual cockpit conditions, were used for the ratio of the speech to cockpit noise sound pressure levels. Speech intelligibility was significantly better with ANR compared to no ANR for both S/N conditions. Variability of speech intelligibility among pilots was also significantly less with ANR. When the stock helmet was used with ANR turned off, the average PB Word speech intelligibility score was below the Normally Acceptable level. In comparison, it was above that level with ANR on in both S/N levels.
Document ID
19900019194
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Chan, Jeffrey W. (DEV AIR Technical Associates Menlo Park, CA., United States)
Simpson, Carol A. (Psycho-Linguistic Research Associates Woodside, CA., United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1990
Subject Category
Aircraft Communications And Navigation
Report/Patent Number
NAS 1.26:177564
USAAVSCOM-TR-90-G-1
NASA-CR-177564
A-90264
AD-A227153
Accession Number
90N28510
Funding Number(s)
CONTRACT_GRANT: NAS2-13188
PROJECT: RTOP 505-61-51
CONTRACT_GRANT: NAS2-12425
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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