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

Journal of the Acoustical Society of America

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Next Issue

Jan 2008

Volume 123, Issue 1, pp. 1-EL20

Return to All Sections
back to top
RSS Feeds

On fiber optic probe hydrophone measurements in a cavitating liquid

Aaldert Zijlstra and Claus Dieter Ohl

J. Acoust. Soc. Am. Volume 123, Issue 1, pp. 29-32 (2008); (4 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The measurement of high-pressure signals is often hampered by cavitation activity. The usage of a fiber optic probe hydrophone possesses advantages over other hydrophones, yet when measuring in a cavitating liquid large variations in the signal amplitude are found; in particular when the pressure signal recovers back to positive values. With shadowgraphy the wave propagation and cavity dynamics are imaged and the important contributions of secondary shock waves emitted from collapsing cavitation bubbles are revealed. Interestingly, just adding a small amount of acidic acid reduces the cavitation activity to a large extent. With this treatment an altered primary pressure profile which does not force the cavitation bubbles close to fiber tip into collapse has been found. Thereby, the shot-to-shot variations are greatly reduced.
Show PACS
43.35.Ei Acoustic cavitation in liquids
43.35.Yb Ultrasonic instrumentation and measurement techniques

Power-output regularization in global sound equalization

Nick Stefanakis, John Sarris, George Cambourakis, and Finn Jacobsen

J. Acoust. Soc. Am. Volume 123, Issue 1, pp. 33-36 (2008); (4 pages) | Cited 3 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The purpose of equalization in room acoustics is to compensate for the undesired modification that an enclosure introduces to signals such as audio or speech. In this work, equalization in a large part of the volume of a room is addressed. The multiple point method is employed with an acoustic power-output penalty term instead of the traditional quadratic source effort penalty term. Simulation results demonstrate that this technique gives a smoother decline of the reproduction performance away from the control points.
Show PACS
43.55.Br Room acoustics: theory and experiment; reverberation, normal modes, diffusion, transient and steady-state response
43.38.Md Sound recording and reproducing systems, general concepts
43.60.Pt Signal processing techniques for acoustic inverse problems

Comment on “A geometric representation of spectral and temporal vowel features: Quantification of vowel overlap in three linguistic varieties” [J. Acoust. Soc. Am. 119, 2334–2350 (2006)]

Geoffrey Stewart Morrison

J. Acoust. Soc. Am. Volume 123, Issue 1, pp. 37-40 (2008); (4 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In a recent paper by Wassink [J. Acoust Soc. Am. 119, 2334–2350 (2006)] the spectral overlap assessment metric (SOAM) was proposed for quantifying the degree of acoustic overlap between vowels. The SOAM does not fully take account of probability densities. An alternative metric is proposed which is based on quadratic discriminant analysis and takes account of probability densities in the form of a posteriori probabilities. Unlike the SOAM, the a posteriori probability-based metric allows for a direct comparison of vowel overlaps calculated using different numbers of dimensions, e.g., three dimensions (Fl, F2, and duration) versus two dimensions (Fl and F2).
Show PACS
43.70.Jt Instrumentation and methodology for speech production research
Return to All Sections
Close

Home Publications Meetings Contact ASA Site Map Back to Top

Copyright © Acoustical Society of America

close