The near field, Westervelt far field, and inverse-law far field of the audio sound generated by parametric array loudspeakers.

Zhong, J; Kirby, R; Qiu, X

The near field, Westervelt far field, and inverse-law far field of the audio sound generated by parametric array loudspeakers.

Zhong, J

Kirby, R

Qiu, X

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Publisher:: ACOUSTICAL SOC AMER AMER INST PHYSICS
Publication Type:: Journal Article
Citation:: The Journal of the Acoustical Society of America, 2021, 149, (3), pp. 1524
Issue Date:: 2021-03

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Field	Value	Language
dc.contributor.author	Zhong, J https://orcid.org/0000-0002-9972-8004
dc.contributor.author	Kirby, R https://orcid.org/0000-0002-3520-1377
dc.contributor.author	Qiu, X
dc.date.accessioned	2021-04-28T06:00:09Z
dc.date.available	2021-04-28T06:00:09Z
dc.date.issued	2021-03
dc.identifier.citation	The Journal of the Acoustical Society of America, 2021, 149, (3), pp. 1524
dc.identifier.issn	0001-4966
dc.identifier.issn	1520-8524
dc.identifier.uri	http://hdl.handle.net/10453/148458
dc.description.abstract	The near and far fields of traditional loudspeakers are differentiated by whether the sound pressure amplitude is inversely proportional to the propagating distance. However, the audio sound field generated by a parametric array loudspeaker (PAL) is more complicated, and in this article it is proposed to be divided into three regions: near field, Westervelt far field, and inverse-law far field. In the near field, the audio sound experiences strong local effects and an efficient quasilinear solution is presented. In the Westervelt far field, local effects are negligible so that the Westervelt equation is used, and in the inverse-law far field, a simpler solution is adopted. It is found that the boundary between the near and Westervelt far fields for audio sound lies at approximately a<sup>2</sup>/λ - λ/4, where a is transducer radius and λ is ultrasonic wavelength. At large transducer radii and high ultrasonic frequencies, the boundary moves close to the PAL and can be estimated by a closed-form formula. The inverse-law holds for audio sound in the inverse-law far field and is more than 10 meters away from the PAL in most cases. With the proposed classification, it is convenient to apply appropriate prediction models to different regions.
dc.format	Print
dc.language	eng
dc.publisher	ACOUSTICAL SOC AMER AMER INST PHYSICS
dc.relation.ispartof	The Journal of the Acoustical Society of America
dc.relation.isbasedon	10.1121/10.0003606
dc.rights	info:eu-repo/semantics/embargoedAccess
dc.subject.classification	Acoustics
dc.title	The near field, Westervelt far field, and inverse-law far field of the audio sound generated by parametric array loudspeakers.
dc.type	Journal Article
utslib.citation.volume	149
utslib.location.activity	United States
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Mechanical and Mechatronic Engineering
utslib.copyright.status	open_access	*
utslib.copyright.embargo	2021-09-30T00:00:00+1000Z
dc.date.updated	2021-04-28T06:00:07Z
pubs.issue	3
pubs.publication-status	Published
pubs.volume	149
utslib.citation.issue	3

Abstract:

The near and far fields of traditional loudspeakers are differentiated by whether the sound pressure amplitude is inversely proportional to the propagating distance. However, the audio sound field generated by a parametric array loudspeaker (PAL) is more complicated, and in this article it is proposed to be divided into three regions: near field, Westervelt far field, and inverse-law far field. In the near field, the audio sound experiences strong local effects and an efficient quasilinear solution is presented. In the Westervelt far field, local effects are negligible so that the Westervelt equation is used, and in the inverse-law far field, a simpler solution is adopted. It is found that the boundary between the near and Westervelt far fields for audio sound lies at approximately a²/λ - λ/4, where a is transducer radius and λ is ultrasonic wavelength. At large transducer radii and high ultrasonic frequencies, the boundary moves close to the PAL and can be estimated by a closed-form formula. The inverse-law holds for audio sound in the inverse-law far field and is more than 10 meters away from the PAL in most cases. With the proposed classification, it is convenient to apply appropriate prediction models to different regions.

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http://hdl.handle.net/10453/148458