A Self-Silenced Sound Beam

Document type: Journal Articles
Article type: Original article
Peer reviewed: Yes
Author(s): Claes Hedberg, Kristian Haller, Tomoo Kamakura
Title: A Self-Silenced Sound Beam
Journal: Acoustical Physics
Year: 2010
Volume: 56
Issue: 5
Pagination: 637-639
ISSN: 1063-7710
Publisher: Pleiades Publishing
URI/DOI: 0.1134/S1063771010050064
ISI number: 000281713600006
Organization: Blekinge Institute of Technology
Department: School of Engineering - Dept. of Mechanical Engineering (Sektionen för ingenjörsvetenskap - avd. för maskinteknik)
School of Engineering S- 371 79 Karlskrona, School of Engineering S- 371 79 Karlskrona
+46 455 38 50 00
Authors e-mail: claes.hedberg@bth.se, kamakura@ee.uec.ac.jp
Language: English
Abstract: Parametric loudspeakers are transmitting two high power ultrasound frequencies. During propagation through the air, nonlinear interaction creates a narrow sound beam at the difference frequency, similar to a light beam from a torch. In this work is added the physical phenomenon of propagation cancellation, leaving a limited region within which the sound can be heard—a 1 meter long cylinder with diameter 8 cm.
It is equivalent to a torch which would only illuminate objects within 1 meter. The concept is demonstrated both in simulation and in experiment.
Subject: Physical Acoustics\General
Mechanical Engineering\Structural Dynamics
Note: http://www.maik.ru/cgi-perl/journal.pl?lang=eng&name=acoust