Acoustical Science and Technology
Online ISSN : 1347-5177
Print ISSN : 1346-3969
Volume 33 , Issue 6
Showing 1-12 articles out of 12 articles from the selected issue
  • Kensaku Fujii, Yutaka Okamoto, Masahiro Itou, Mitsuji Muneyasu, Masaka ...
    2012 Volume 33 Issue 6 Pages 339-347
    Published: June 01, 2012
    Released: November 02, 2012
    We propose a two-channel adaptive algorithm efficiently utilizing independent components slightly involved in reference signals. In active noise control systems, the conventional methods of adding independent components to the reference signals or deliberately changing the correlation between the reference signals are inapplicable, because the reference signals are only detected by noise detection microphones. We have hence presented an adaptive algorithm that does not require the addition of the independent components or the deliberate change to the reference signals. However, this algorithm has three drawbacks. The first is that one of the convergence conditions is described by unmeasurable signals. The second is that pre-estimation of the reference signal power ratio is required. The third is that unknown acoustic paths cannot be identified when the reference signals have high cross-correlation between different sample times. In this work, we derive a new algorithm without the drawbacks and verify, using computer simulations, that the derived algorithm can successfully identify the unknown acoustic paths. The two-channel active noise control system using the simultaneous equations method is thereby expected to provide a high noise reduction effect.
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  • Tokihiko Kaburagi
    2012 Volume 33 Issue 6 Pages 348-358
    Published: June 01, 2012
    Released: November 02, 2012
    A method for analyzing the behavior of flow passing through an asymmetrical glottal channel is presented. The method assumes the formation of a thin boundary layer near the glottal wall and an interaction between the boundary layer and the core flow. The core flow velocity is estimated in two dimensions employing a method of potential flow analysis, while the characteristic quantities of the boundary layer are determined by solving the integral momentum relation on the basis of the similarity of the velocity profiles within the layer. Estimation results for the volume flow rate, effective flow velocity, pressure distribution, driving force of the vocal folds, and flow separation point are presented for a total of 315 glottal configurations obtained by varying the angle of each vocal fold and the minimum glottal height. The results indicate that the boundary layer tends to reduce the effect of channel asymmetry, and the imbalance of the aerodynamic quantities between the two vocal folds is small unless the glottis widely opens and the angular difference of the vocal folds is considerable.
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  • Yoshiko Arimoto, Hiromi Kawatsu, Sumio Ohno, Hitoshi Iida
    2012 Volume 33 Issue 6 Pages 359-369
    Published: June 01, 2012
    Released: November 02, 2012
    For the purpose of constructing a naturalistic emotional speech database, a novel paradigm of collecting naturalistic emotional speech during a spontaneous Japanese dialog was proposed. The proposed paradigm was assessed by investigating whether the collected speech contains and conveys rich emotions psychologically and acoustically. To encourage speakers to experience and express their natural and vivid emotions, a Massively Multiplayer Online Role-Playing Game (MMORPG) was adopted as a task for speakers. They were asked to play the MMORPG together while discussing strategies to achieve their tasks through a voice chat system. The recording was performed for one hour per speaker. The total recording time was approximately 14 hours. The results of emotional labeling for the collected speech supported the validity of the paradigm showing higher interlabeler agreement than the chance levels. In addition, it was revealed that the paradigm is superior in the quantity of emotional speech to other paradigm by showing a significantly higher rate of labeling instances for our speech material (73%, χ2(2) = 27659.87, p < 0.001) than other speech materials. Finally, an acoustical analysis supported the validity of the paradigm, showing a significant difference between the nonemotional utterances and the emotional utterances (p < 0.05).
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