Helicopter Aural Detectability
Abstract
The principal objective of the study is to develop the methodology for the prediction of helicopter aural detection thresholds from measured or estimated parameters of significance. The subjective aspects of helicopter noise are discussed. A review is presented of the effects of atmospheric and terrain features upon the observed sound, and of the limitations in the measurement and analysis of helicopter noise. An experimental program is described, in which a group of subjects listened to a large number of synthetic and recorded helicopter sounds inside a specially designed acoustic chamber. Through these experiments, a model for calculating aural detection thresholds is developed, tested, and found to be accurate to within plus or minus 4dB. Appendices to the report include detailed instructions for applying several versions of the developed method and also provide simplified procedures for estimating propagation losses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1971
- Accession Number
- AD0730788
Entities
People
- John B. Ollerhead