Author: L. D. PopePublisher:
ISBN:
Category : Airplane sounds
Languages : en
Pages : 184
Book Description
Propeller Aircraft Interior Noise Model
Author: L. D. PopePublisher:
ISBN:
Category : Airplane sounds
Languages : en
Pages : 184
Book Description
Propeller Aircraft Interior Noise Model
Author: L. D. PopePropeller Aircraft Interior Noise Model: Utilization Study and Validation
Author: Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes
Author: Clemans A. PowellPublisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 40
Book Description
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.
An Improved Source Model for Aircraft Interior Noise Studies
Author: Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes
Author: National Aeronautics and Space Adm NasaPublisher: Independently Published
ISBN: 9781723748059
Category : Science
Languages : en
Pages : 40
Book Description
Active noise control technology offers the potential for weight-efficient aircraft 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.Powell, Clemans A. and Sullivan, Brenda M.Langley Research CenterEFFECTIVENESS; ACTIVE CONTROL; SENSITIVITY; PROPELLER NOISE; NOISE REDUCTION; AIRCRAFT NOISE; PROPELLERS; PROCEDURES; PASSENGERS; LOUDNESS; JUDGMENTS; CORRECTION; AIRCRAFT COMPARTMENTS; SOUND TRANSDUCERS
Effects of Propeller Rotation Direction on Airplane Interior Noise Levels
Author: Effects of Propeller Rotation Direction on Airplane Interior Noise Levels
Author: Conrad M. WillisPublisher:
ISBN:
Category : Aircraft cabins
Languages : en
Pages : 40
Book Description
Sources and Characteristics of Interior Noise in General Aviation Aircraft
Author: John J. CatherinesPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 44
Book Description
Aircraft Interior Noise Reduction by Alternate Resonance Tuning
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722056759
Category :
Languages : en
Pages : 42
Book Description
Existing interior noise reduction techniques for aircraft fuselages perform reasonably well at higher frequencies, but are inadequate at lower frequencies, particularly with respect to the low blade passage harmonics with high forcing levels found in propeller aircraft. A method is being studied which considers aircraft fuselage lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. Adjacent panels would oscillate at equal amplitude, to give equal source strength, but with opposite phase. Provided these adjacent panels are acoustically compact, the resulting cancellation causes the interior acoustic modes to become cutoff, and therefore be non-propagating and evanescent. This interior noise reduction method, called Alternate Resonance Tuning (ART), is currently being investigated both theoretically and experimentally. This new concept has potential application to reducing interior noise due to the propellers in advanced turboprop aircraft as well as for existing aircraft configurations. Bliss, Donald B. and Gottwald, James A. and Srinivasan, Ramakrishna and Gustaveson, Mark B. Unspecified Center NAG1-722...