THE JOURNAL OF THE ACOUSTICAL SOCIETY OF JAPAN

The relationship between the improved S.E.A. method and probabilistic evaluation with discrete level for a sound insulating system.

Mitsuo Ohta, Hirofumi Iwasige

Article type: Article
1982 Volume 38 Issue 7 Pages 395-405
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_395

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A new universal probability expression with discrete levels is theoretically found as the basis of the probabilistic evaluation for sound transmission. This expression can be derived in the several expansion forms with mathematical difference operations, and so, is suitable to treat directly the actually observed digital data in the numerical form. As its application, a new method of the probability evaluation is proposed for double-wall and single-wall, sound insulating systems. In this case, the probability distribution function of the output fluctuation can be predicted with the evaluation of energy transmission coefficients by use of the improved S. E. A. (Statistical Energy Analysis) method for each sound insulating system. Our new probabilistic estimation of the output fluctuation will be affected by the statistical character of the input, and the proper sound transmission characteristic {a_i} of the system. This general probability expression is given in a statistical expansion form taking the well-known binomial distribution as the first term. Agreement between theory and experimentation is effectively confirmed for these cases.

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The design system of loudspeaker network by the optimization method.

Takafumi Ueno, Shin'ichiro Ishii

Article type: Article
1982 Volume 38 Issue 7 Pages 406-413
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_406

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A new approach to the design of loudspeaker crossover network is presented whereby the component values of the network are selected by a digital computer such that the value of a functional is minimized. The functional represents the error between the desired and actual frequency response of the system. The crossover networks are normally designed using a mixture of simple analytical filter theory and trial and error. To overcome the limitation of the trial and error technique, we have developed a new design system of loudspeaker network using a nonlinear optimization method. The features are as follows : 1) Fletcher-Powell's method was chosen by the authors. 2) The suer can input an arbitrary desired frequency response from the data tablet. 3) The component values of the network can be obtained in the standard series. An example of three-way network of 12 dB/oct. filters is shown. Aster 20 iterations, The deviation of the frequency response is decreased from 10 dB to 3 dB. The CPU time required for minimization is about 2 min. The time for loudspeaker network design is reduced to 1/10 of the conventional design.

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Nonlinear electrical circuit model of hair cell.

Kohji Motoishi, Yosiro Oono

Article type: Article
1982 Volume 38 Issue 7 Pages 414-420
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_414

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The dynamical behaviour of a nonlinear electrical circuit model of a hair cell is studied and shown to agree with recent physiological data. The feature of this model is that is has a nonlinear resistance corresponding to the potassium channels in the membrane of the squid giant axon. The behaviour of this model in response to mechanical and electrical stimuli agrees well with Hudspeth and Corey's data for the mechano-electrical transduction properties of the hair cell. Another analysis on the behavior of the model in response to injection of current steps shows that the model can qualitatively account for the ringing phenomenon observed by Crawford and Fettiplace.

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Whether dBA or dB (A) ?

Sakae Morita

Article type: Article
1982 Volume 38 Issue 7 Pages 421-
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_421

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Signal generator using CMOS microprocessor for evaluating room acoustics.

Tadashi Takise

Article type: Article
1982 Volume 38 Issue 7 Pages 422-428
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_422

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Monitor loudspeaker system.

Yukio Takahashi, Shinji Ohashi

Article type: Article
1982 Volume 38 Issue 7 Pages 429-435
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_429

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On the study of architectural acoustics in China.

Bing-Lin Wang

Article type: Article
1982 Volume 38 Issue 7 Pages 436-441
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_436

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[title in Japanese]

Article type: Appendix
1982 Volume 38 Issue 7 Pages 442-
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_442_1

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[title in Japanese]

Article type: Appendix
1982 Volume 38 Issue 7 Pages 442-
Published: July 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.7_442_2

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