日本音響学会誌
Online ISSN : 2432-2040
Print ISSN : 0369-4232
14 巻, 3 号
選択された号の論文の5件中1~5を表示しています
  • 佐藤 英男
    原稿種別: 本文
    1958 年 14 巻 3 号 p. 217-226
    発行日: 1958/09/30
    公開日: 2017/06/02
    ジャーナル フリー
    Presently in Japan, as a random noise measurement, a method of sample survey in which the deflections of S. L. -meter read mechanically every 5 seconds is being used. If N. L. -variation from time to time is devided into many N. L. s having equal durations which are sufficiently small, in each of them N. L. is almost constant and each of them is considered representing one 'instant N. L. ' The total noise phenomenon is considered as a group of many 'instant N. L. s', therefore, the probability of a certain N. L. value coinciding with one of the readings (measured instant N. L. ). equals to number-rate of this valued instant N. L. in that group of N. L. s, and furthermore as each instant N. L. has equal duration, our measurement becomes that of the Time-rate. In this paper, we took up error functions for several statistics of N. L. readings and checked them experimentally with over 1, 000 readings every 5 sec. in equal situations on the representative highways in Tokyo city. We learned, by this check, the N. L. -variation has frequently an inclination to fluctuate with longer period than the measuring interval (5 sec. ) and Time-rate in some observing session is not stable. Influenced by such phenomenon variance calculated from measured readings are unable to give us any reliable estimation of mathematical mean's variance and therefore, it becomes necessary for us in applying "t-test" to minimize this effect as well as we want in practical use. For instance, we must check in every case that the ambient noise have no effect on the main measurement, but as it is impossible to measure it separately in the same observing session, the ambient noise in main measurement and check becomes different and t-test for their difference has no practical meaning. As a mean of eliminating this effect, we proposed in this paper in adopting the process of taking a small number of readings in one session and adopting, for instance, their mathematical mean as one observed value. Those observed values, with their observing sessions randomized, fluctuate with variance containing one of the longer period inclination and, so satisfactory results are obtainable when t-test are performed.
  • 佐藤 孝二, 子安 勝
    原稿種別: 本文
    1958 年 14 巻 3 号 p. 227-234
    発行日: 1958/09/30
    公開日: 2017/06/02
    ジャーナル フリー
    So far, it has been said that the sound absorption of persons and theatre chairs measured in the reverberation chamber does not agree with the sound absorption measured in actual situations. This is also the same in the case of added absorption by caused audience taking their seats in theatre chairs. In this report, measurements of absorption of persons and theatre chairs, which are directly applicable to the actual use, are mentioned. Reverberation chamber used for this research is the chamber of our institute ( 513m^3, nonparallel walls). Following results are obtained: (1) It is possible to measure the absorption of heavily upholstered theatre chairs without regard to the number of chairs (from 5 to 20 seats), or to the arrangement of chairs. This absorption shows a good agreement with the absorption measured in actual theatres (Fig. 4). (2) As to the absorption of persons seated in chairs made by plywood (0. 02〜0. 03m-sabin per chair), it was shown that the absorption was affected by the arrangement of seats (Fig. 6). By making proper correction of these data, it was found that the absorption of person could be measured in the reverberation chamber. This absorption is in good agreement with absorption resulting in ordinary rooms. (3) By using above method, the absorption of Japanese persons was obtained (Fig. 7). At frequencies below 1000 cycles per second, the absorption varies considerably with different seasons. (4) Absorption added by seating audience in heavily upholstered theatre chairs was also measured by the same method. The effect of added absorption on the reverberation time of theatres seems to be negligible in the case of chairs used in this research.
  • 弘田 仁哉, 吉沢 典男, 荒井 賢一, 関根 弘, 桜井 和人
    原稿種別: 本文
    1958 年 14 巻 3 号 p. 235-240
    発行日: 1958/09/30
    公開日: 2017/06/02
    ジャーナル フリー
    The authors have applied the prosthetic treatment to a case of dysarthria caused by the surgical operation for maxillary cancer. The following results were obtained by observing the effects of this treatment through a sonagraph. 1) Patient rehabilitated her articulation remarkably by the prosthetic treatment. 2) Notable rehabilitation were observed on the sound spectrogram of some vowels and consonants such as "i", "e", "w" or "k", "t", "s". 3) Nasalization of vowels still remained in spite of the treatment. This points ont the fact that the prosthetic treatment performed on such case leaves more to be investigated phonetically or acoustically wise.
  • 原稿種別: 付録等
    1958 年 14 巻 3 号 p. 240-
    発行日: 1958/09/30
    公開日: 2017/06/02
    ジャーナル フリー
  • 近野 正
    原稿種別: 本文
    1958 年 14 巻 3 号 p. 241-262
    発行日: 1958/09/30
    公開日: 2017/06/02
    ジャーナル フリー
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