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Laboratory study of effects of sonic boom shaping on subjective loudness and acceptabilityA laboratory study was conducted to determine the effects of sonic boom signature shaping on subjective loudness and acceptability. The study utilized the sonic boom simulator at the Langley Research Center. A wide range of symmetrical, front-shock-minimized signature shapes were investigated together with a limited number of asymmetrical signatures. Subjective loudness judgments were obtained from 60 test subjects by using an 11-point numerical category scale. Acceptability judgments were obtained using the method of constant stimuli. Results were used to assess the relative predictive ability of several noise metrics, determine the loudness benefits of detailed boom shaping, and derive laboratory sonic boom acceptability criteria. These results indicated that the A-weighted sound exposure level, the Stevens Mark 7 Perceived Level, and the Zwicker Loudness Level metrics all performed well. Significant reductions in loudness were obtained by increasing front-shock rise time and/or decreasing front-shock overpressure of the front-shock minimized signatures. In addition, the asymmetrical signatures were rated to be slightly quieter than the symmetrical front-shock-minimized signatures of equal A-weighted sound exposure level. However, this result was based on a limited number of asymmetric signatures. The comparison of laboratory acceptability results with acceptability data obtained in more realistic situations also indicated good agreement.
Document ID
19930002432
Acquisition Source
Legacy CDMS
Document Type
Technical Publication (TP)
Authors
Leatherwood, Jack D. (NASA Langley Research Center Hampton, VA, United States)
Sullivan, Brenda M. (Lockheed Engineering and Sciences Co. Hampton, VA., United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1992
Subject Category
Acoustics
Report/Patent Number
NAS 1.60:3269
NASA-TP-3269
L-17050
Accession Number
93N11620
Funding Number(s)
PROJECT: RTOP 537-03-21-03
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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