• Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Journal of the Acoustical Society of America

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

Jun 2005

Volume 117, Issue 6, pp. 3335-3971

Return to All Sections
back to top
RSS Feeds

Acoustic characteristics of an electrodynamic planar digital loudspeaker using noise shaping technology

Atsushi Hayama, Kenji Furihata, David K. Asano, and Takesaburo Yanagisawa

J. Acoust. Soc. Am. Volume 117, Issue 6, pp. 3636-3644 (2005); (9 pages)

Online Publication Date: 31 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The present study extends our previous work [Furihata et al., J. Acoust. Soc. Am. 114, 174–184 (2003)] by investigating our electrodynamic planar loudspeaker when driven by a 12 bit digital signal with noise shaping. Changing the structure of the loudspeaker can lead to improvement, but in this paper improvements that can be made using signal processing are investigated. Results show that the digital loudspeaker demonstrated good linearity over its 84 dB dynamic range from 40 Hz to 10 kHz. This shows that a 12 bit digital loudspeaker which is equivalent to a 16 bit one is possible. © 2005 Acoustical Society of America.
Show PACS
43.38.Dv Electromagnetic and electrodynamic transducers
43.38.Ja Loudspeakers and horns, practical sound sources

Forced responses of solid axially polarized piezoelectric ceramic finite cylinders with internal losses

D. D. Ebenezer, K. Ravichandran, R. Ramesh, and Chandramouli Padmanabhan

J. Acoust. Soc. Am. Volume 117, Issue 6, pp. 3645-3656 (2005); (12 pages)

Online Publication Date: 31 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method is presented to determine the forced responses of piezoelectric cylinders using weighted sums of only certain exact solutions to the equations of motion and the Gauss electrostatic conditions. One infinite set of solutions is chosen such that each field variable is expressed in terms of Bessel functions that form a complete set in the radial direction. Another infinite set of solutions is chosen such that each field variable is expressed in terms of trigonometric functions that form a complete set in the axial direction. Another solution is used to account for the electric field that can exist even when there is no vibration. The weights are determined by using the orthogonal properties of the functions and are used to satisfy specified, arbitrary, axisymmetric boundary conditions on all the surfaces. Special cases including simultaneous mechanical and electrical excitation of cylinders are presented. All numerical results are in excellent agreement with those obtained using the finite element software ATILA. For example, the five lowest frequencies at which the conductance and susceptance of a stress-free cylinder, of length 10 mm and radius 5 mm, reach a local maximum or minimum differ by less than 0.01% from those computed using ATILA. © 2005 Acoustical Society of America.
Show PACS
43.38.Ar Transducing principles, materials, and structures: general
43.38.Fx Piezoelectric and ferroelectric transducers
43.20.Bi Mathematical theory of wave propagation
43.40.At Experimental and theoretical studies of vibrating systems

On the externalization of virtual sound images in headphone reproduction: A Wiener filter approach

Sang-Myeong Kim and Wonjae Choi

J. Acoust. Soc. Am. Volume 117, Issue 6, pp. 3657-3665 (2005); (9 pages) | Cited 2 times

Online Publication Date: 31 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In-head localization of sound images is a critical problem in headphone reproduction. The paper investigates the degree of externalization in terms of the distance of auditory images for various synthesis and reproduction cases. An effective binaural headphone system was constructed by way of binaural synthesis using head-related impulse responses and individual headphone equalization using Wiener filter theory. The headphone system designed had an average reproduction performance error of 2.4% for five subjects with a random noise input, and was used to perform some subjective tests with a set of virtual sources equally spaced and distanced from the center of each subject’s head in the horizontal plane. The effects of individual and nonindividual binaural syntheses and those of equalized and nonequalized reproductions were separately investigated. In the tests, each subject was instructed to indicate the distance of auditory images. The results obtained demonstrate that individual equalization is important for externalization, and individual synthesis is important for consistent distance perception. Thus, a combined use of both individual equalization and individual synthesis resulted in externalized sound images of a consistent distance. © 2005 Acoustical Society of America.
Show PACS
43.38.Vk Stereophonic reproduction
43.38.Md Sound recording and reproducing systems, general concepts
43.66.Pn Binaural hearing
43.66.Qp Localization of sound sources
43.66.Yw Instruments and methods related to hearing and its measurement
Return to All Sections
Close

Home Publications Meetings Contact ASA Site Map Back to Top

Copyright © Acoustical Society of America

close