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| Author | : |
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| Total Pages | : 22 |
| Release | : 1990 |
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| Author | : |
| Publisher | : |
| Total Pages | : 28 |
| Release | : 1986 |
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| Author | : Jack D. Leatherwood |
| Publisher | : |
| Total Pages | : 32 |
| Release | : 1987 |
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| Author | : David A. McCurdy |
| Publisher | : |
| Total Pages | : 48 |
| Release | : 1988 |
| Genre | : Airplanes |
| ISBN | : |
| Author | : Clemans A. Powell |
| Publisher | : |
| Total Pages | : 40 |
| Release | : 2000 |
| Genre | : Acoustical engineering |
| ISBN | : |
Active noise control technology offers the potential for weight-efficient interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.
| Author | : David A. McCurdy |
| Publisher | : |
| Total Pages | : 76 |
| Release | : 1991 |
| Genre | : Airplanes |
| ISBN | : |
| Author | : National Aeronautics and Space Administration (NASA) |
| Publisher | : Createspace Independent Publishing Platform |
| Total Pages | : 148 |
| Release | : 2018-07-18 |
| Genre | : |
| ISBN | : 9781723183973 |
The measurement and analysis procedures are documented, and the results of interior noise control ground tests conducted on a DC-9 aircraft test section are summarized. The objectives of these tests were to study the fuselage response characteristics of treated and untreated aircraft with aft-mount advanced turboprop engines and to analyze the effectiveness of selected noise control treatments in reducing passenger cabin noise on these aircraft. The results of fuselage structural mode surveys, cabin cavity surveys and sound intensity surveys are presented. The performance of various structural and cabin sidewall treatments is assessed, based on measurements of the resulting interior noise levels under simulated advanced turboprop excitation. Simpson, Myles A. and Cannon, Mark R. and Burge, Paul L. and Boyd, Robert P. Unspecified Center AIRCRAFT COMPARTMENTS; DC 9 AIRCRAFT; NOISE PREDICTION (AIRCRAFT); NOISE REDUCTION; NOISE TOLERANCE; SOUND TRANSMISSION; TURBOPROP AIRCRAFT; ACOUSTICS; FULL SCALE TESTS; FUSELAGES; GROUND TESTS; NOISE INTENSITY...
| Author | : David A. McCurdy |
| Publisher | : |
| Total Pages | : 92 |
| Release | : 1990 |
| Genre | : Airplanes |
| ISBN | : |
| Author | : National Aeronautics and Space Administration (NASA) |
| Publisher | : Createspace Independent Publishing Platform |
| Total Pages | : 44 |
| Release | : 2018-06-30 |
| Genre | : |
| ISBN | : 9781722093464 |
Two experiments were conducted to quantify the annoyance of people to advanced turboprop (propfan) aircraft flyover noise. The objectives were to: (1) determine the effects on annoyance of various tonal characteristics; and (2) compare annoyance to advanced turboprops with annoyance to conventional turboprops and jets. A computer was used to produce realistic, time-varying simulations of advanced turboprop aircraft takeoff noise. In the first experiment, subjects judged the annoyance of 45 advanced turboprop noises in which the tonal content was systematically varied to represent the factorial combinations of five fundamental frequencies, three frequency envelope shapes, and three tone-to-broadband noise ratios. Each noise was presented at three sound levels. In the second experiment, 18 advanced turboprop takeoffs, 5 conventional turboprop takeoffs, and 5 conventional jet takeoffs were presented at three sound pressure levels to subjects. Analysis indicated that frequency envelope shape did not significantly affect annoyance. The interaction of fundamental frequency with tone-to-broadband noise ratio did have a large and complex effect on annoyance. The advanced turboprop stimuli were slightly less annoying than the conventional stimuli. Mccurdy, David A. Langley Research Center RTOP 535-03-11-03...
| Author | : J.S. Mixson |
| Publisher | : |
| Total Pages | : 11 |
| Release | : 1982 |
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