This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Sound Intensity Visualization with a Rigid Spherical Microphone Array in a Vehicle Cabin
Technical Paper
2009-01-2176
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Measurement of the sound intensity vector distribution is a useful way to identify noise sources in a vehicle especially at low frequencies. Due to the effect of standing waves, it is difficult to identify the source location from the sound pressure measurement at the driver's ear position. Direct measurements, such as scanning the entire vehicle cabin with a three-dimensional sound intensity probe is very time consuming, and is not able to track temporal and spatial changes in the sources.
In this paper, an approach is presented that provides a prediction of the vector sound intensity field throughout a volume exterior to a rigid spherical measurement array consisting of flush mounted microphones. The theory is called spherical near-field acoustic holography (Sp-NAH) based on spherical harmonic expansions of the measured sound pressure field with the radial variation of the near-field pressure obtained using the Green's function with vanishing normal derivative at the rigid sphere surface.
Measurement results showing volumetric sound intensity vector reconstructions in a vehicle cabin are presented. The measurement equipment was used in previous demonstrations to visualize the acoustic field using a spherical beamforming (Sp-BF) technique superimposed on pictures from on-board cameras. Comparison between Sp-NAH and Sp-BF is also presented and discussed in this paper.
In this study, sound intensity reconstructions using Sp-NAH are successful in locating and quantifying sources, demonstrating the usefulness of this technique in an enclosed space such as a vehicle cabin, an aircraft cabin, a small room, etc.
Authors
Citation
Takashima, K., Nakagawa, H., and Williams, E., "Sound Intensity Visualization with a Rigid Spherical Microphone Array in a Vehicle Cabin," SAE Technical Paper 2009-01-2176, 2009, https://doi.org/10.4271/2009-01-2176.Also In
References
- Nakajima Hirofumi Yamanaka Takaaki Nakagawa Hiroshi “Beamforming using indefinite terms for arbitrary located microphones” proc. of autumn meeting of the acoustical society of Japan 2002 (In Japanese)
- Yamanaka Takaaki et al “Identification of sound sources with sphere-baffled microphone array and CCD cameras” proc. of autumn meeting of the acoustical society of Japan 2002 (In Japanese)
- Takashima Kazuhiro Nakagawa Hiroshi “The omni-directional sound source analysis for evaluating the vehicle sound insulation performance” proc. of Spring Meeting of the Korean Society for Noise and Vibration Engineering 2007
- Li Ye Kasaki Naohiko Tsunoda Hiroyuki Nakamura Takaki Nouzawa Takahide “Evaluation of Wind Noise Sources Using Experimental and Computational Methods” SAE 2006 World Congress Detroit, Michigan April 3-6 2006
- Kawano Junichi Amakasu Junichi Tanaka Tsutomu “Noise Detection Technology Development for Car Cabin” SAE 2008 World Congress Detroit Michigan April 14-17 2008
- Alan Mouch Timothy Takashima Kazuhiro Cheng Sung-Ping “Objective Measurement and Source Location of Automotive Squeak and Rattles” SAE 2009 Noise and Vibration Conference and Exhibition May 2009 (to be published)
- Williams Earl G. Valdivia Nicolas Herdic Peter C. Klos Jacob “Volumetric acoustic vector intensity imager” Journal Acoustical Society of America 120 4 1887 1897 2006
- Williams Earl. G. Takashima Kazuhiro “Vector intensity reconstructions in a volume surrounding a rigid spherical measurement array” ASA-EAA Joint Conference (Acoustics'08 Paris) June 2008
- Takashima Kazuhiro Nakagawa Hiroshi Williams Earl G. “Vector intensity measurement with a rigid spherical microphone array in a vehicle cabin” ASA-EAA Joint Conference (Acoustics'08) Paris June 2008
- Williams Earl G. “Fourier Acoustics: Sound Radiation and Nearfield Acoustical Holography” Academic Press London, UK 1999
- Williams Earl G. “Regularization methods for near-field acoustical holography” Journal Acoustical Society of America 110 4 1976 1988 2001