日本音響学会誌
Online ISSN : 2432-2040
Print ISSN : 0369-4232
33 巻 , 11 号
選択された号の論文の10件中1~10を表示しています
  • 守田 栄, 尾股 定夫
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 601-605
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
    A block diagram of the measuring system is shown in Fig. 1. The pick-up of acceleration type is set on the ground surface and at a point on the surface not far from the pick-up struck with a wooden hammer repeatedly. The output of the pick-up is amplified and recorded on an endless tape of a data-recorder. At laboratory the record is reproduced and analyzed by frequency-analyzer of continuously scanning type. We tried preliminary experiments by placing the pick-up on a surface plate. To change the contact condition some sheets of paper were inserted between the pick-up and the surface plate and the number of sheets was changed 1, 2, 4, up to 128. Fig. 2 and Fig. 3 show examples of the results obtained. The pick-up used in the above experiments was that of actual vibration level meter. Next, using a test pick-up as shown in Fig. 4, we examined the relation between the resonant frequency f_0 and the mass of pick-up m_0, and also the relation between f_0 and additive mass m_a attached as shown in the figure. Fig. 5 and Fig. 6 show examples of the results. Then placing a pick-up of actual use on the ground surface under various conditions, we carried out several experiments. (a) Table 1 shows the order of values of resonant frequency on ground surfaces under natural condition and hardened by foot. In some materials and under some conditions we could not expect to harden the ground surface by foot. (b) In some cases we could improve the conditions by scattering certain materials, for examples, a small amount of water on dry sand, and a small amount of soil or sand on deep wet mud. (c) Attaching some kind of frames or rims under the base surface of pick-up, we could also improve the conditions, and example being shown in Fig. 7 and Fig. 8. (d) Fig. 9 shows examples of measurement of ground vibration due to passing trains. The hardening effect of ground surface can be ascertained in the figure obviously.
  • 垣田 有紀, 比企 静雄
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 606-614
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー

    The laryngeal control for pitch change has been studied in order to investigate the prosodic features of speech. This study used a set of models which simulate the characteristics of physiological control in the process of glottal sound generation from the neuromotor command. The advantage of such a method is that the control signals at various levels in the process can be examined by referring to the measured data, such as the electromyogram, the motion of larynx, and the acoustical nature of glottal sound. Electromygrams (EMG) were obtained from the utterance of Japanese word accentuation for five laryngeal muscles (Fig. 1). The speech samples were a nonsense Japanese mora sequence pronounced in isolation with four accentuation types in Tokyo dialect. The patterns of muscles activity, which we call the "continuous neuromotor commands", were obtained by the pulse counting of EMG signals (Fig. 2). The typical thyrogram, which indicates the vertical displacement of the larynx was also examined. As we have previously reported, the thyrogram shows good correspondence with the change in fundamental frequency. Five basic components were assumed to be involved in the continuous neuromotor command considering the linguistically significant characteristics of word accentuation in Japanese. The nature of these components was analyzed qualitatively by an analysis-by-synthesis method, and the components of higher command were derived from the continuous motor command. As the result, the components which specify Japanese word accentuation, and the one specifying the dialect characteristic, were observed separately in the higher command, and the distinction of the accented mora was made only by shifting the timing in the components of accentuation (Fig. 3). The cricothyroid muscle seems to be the primary control of pitch rise, as has been previous reported. In addition, existence of component, whose activity occurs during the decrease in pitch, suggests that pitch is lowered not only by a decrease of the cricothyroid muscle activity, but also by an increase of activity of some other muscles with it (Table 1). Although the involvement of extrinsic laryngeal muscles in the control of fundamental frequency seems to be secondary, the correlation between the activities of these muscles and the vertical displacement of the larynx during pitch change may be explained by reference to the schematized anatomical structure of the larynx (Fig. 4). Based on the mechanical model of the anatomical structure of the larynx (Fig. 5), a change in tension of each muscle and motion of the structure was simulated by the input of the higher commands (Fig. 8). Then, using a model of glottal sound generation (Fig. 6), changes in the fundamental frequency of the glottal sound and in the envelope of glottal volume velocity were derived (Fig. 8) by combining the change in the tension of vocal folds with the change in expiratory pressure through a functional relation of the vocal fold vibration (Fig. 7). Calculated patterns of the vertical displacement of the cricoid tip and change in fundamental frequency show a good correspondence to the measured counterparts (Fig. 9). The effect of the activity of extrinsic muscles on the change in fundamental frequency was also obtained using this model. The rate of the change in the fundamental frequency caused by the contraction of each muscle was estimated in this model by comparison with the change caused by the contraction of both the cricothyroid and vocalis muscles. The rate of increase of fundamental frequency caused by the contraction of the thyrohyoid muscle was estimated to be nearly the same as that caused by only the cricothyroid muscle, while the contraction of only the sternothyroid muscle caused some decrease of the fundamental frequency (Table 2). In this anatomical structure model, the hyoid bone was fixed and the simulation was done based on the

    (View PDF for the rest of the abstract.)

  • 柳沢 猛, 岩本 康男, 鈴木 貞夫
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 615-619
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
    This paper describes a system of automatic piano tuning. Fig. 1 show the block diagram of the system. The standard frequency generator (4) generates signals of the frequency equal to 100 multiples of the standard piano frequency. Deviation detector (5) counts the number of the signals in the gate time of 10 periods of the fundamental of the piano tone. When the number is 1000, it is considered that the frequency of the piano tone is exactly equal to the standard piano frequency. Deviation detector generates positive direct current when the number is smaller than 1000, and negative direct current when the number is larger than 1000. The servomotor (7) is controlled with the direct current, and the tuning pin is turned slowly until the frequency of the piano tone almost agrees to the standard piano frequency. Fig. 3 shows the principle of the deviation detector, and Fig. 4 is the photograph of the automatic tuning device for piano.
  • 東山 三樹夫, 鈴木 明, 吉川 昭吉郎
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 620-625
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
    In this paper, the correlation coefficient of sound pressure in a rectangular reverberant room is studied. The results of numerical calculations at lower frequencies are compared with the experimental ones, and the relation between the geometric acoustics and the wave theory is also mentioned. We consider the sound field in the room excited by narrow band noise. According to Morrow's assumptions, the mean (time-averaged) square pressure distribution along the Y-direction at (x_0, y, z_0) is given by Equations (1) and (3). Here, B^2_m is regarded as representing the directivity power spectrum along the Y-direction at (x_0, y, z_0). The directivity power spectro correspond to those of the traversing microphone spectra scopy. Following the Wiener-Khintchine's theorem with respect to the spatial correlation, it is expected that the correlation coefficient along the Y-direction at (x_0, y, z_0) is given by Equation (5) where B^2_m has been normalized. Here, assuming that B^2_m has an equally probable continuous distribution as shown by Equation (6), the Cook's formula is derived. But the equation (5) is not practical for a finite rectangular room, in particular, at lower frequencies, because, in general, we cannot expect the stationarity with respect to space. Therefore, the correlation coefficient between A(x_0, Y_A, z_0) and B(x_0, Y_A+Δy, z_0) is given by Equation (9) where B^2_m represent the directivity power spectra as stated above. The reverberant room in our laboratory is rectangular as shown in Fig. 1. A block diagram for the measurements is shown in Fig. 2. At 125 Hz (1/3 Oct. ) and 250 Hz (1/3 Oct. ), the theoretical results are compared with the experimental ones, as shown in Figs. 3-12. But the measurements of the directivity power spectra are not performed here. It seems that the condition of the sound source position is reflected those results, and these results correspond to the theoretical ones for the most part. Some practical examples that we can assume theoretically the correlation coefficients of sound pressure in a rectangular reverberant room, are shown here.
  • 桑原 尚夫, 境 久雄
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 626-627
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
  • 上田 光宏, 田辺 克弘
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 628-629
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
  • 高木 興一, 藤木 修, 平松 幸三, 山本 剛夫
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 630-634
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
  • 坂上 丈寿, 安藤 勇夫
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 635-638
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
  • 藤崎 博也, 四日市 章
    原稿種別: 本文
    1977 年 33 巻 11 号 p. 639-641
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
  • 原稿種別: 本文
    1977 年 33 巻 11 号 p. 642-651
    発行日: 1977/11/01
    公開日: 2017/06/02
    ジャーナル フリー
feedback
Top