巻号一覧
35 巻, 6 号
選択された号の論文の7件中1～7を表示しています
- |<
- <
- 1
- >
- >|
-
大貫 秀男, 杉本 利孝原稿種別: 本文
1979 年 35 巻 6 号 p. 301-307
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーThe bending vibration of a tone arm, mostly used in usual disk record players and named 'swing type' is studied. The bending vibration is calculated by the method of transfer matrix and observed experimentally. The frequency response and modes of vibration are numerically calculated. The results obtained are as follows:(1)The first resonant frequency is at about 100 Herz and dominated by length of the pipe and weight of the head mass. (2)Because of the not enough stiffness of the headshell-pipe connector, the second resonant frequency appears. (3)The third resonant frequency is located at nearly 1000Herz. Then, the influence of these bending resonances on the disk record reproduction system and some methods of avoiding the influences are discussed.抄録全体を表示PDF形式でダウンロード (646K) -
石亀 昌明, 安倍 正人, 城戸 健一原稿種別: 本文
1979 年 35 巻 6 号 p. 308-313
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーThis paper describes a new system of estimating spectrum of incident sound from a specified direction. The system is composed of two microphones, one of which is fixed and the other moves along straight line from the fixed one to the specified direction. A uni-beam directivity is achieved when the outputs of the microphones are delayed so that both outputs are in phase for the incident sound from the direction to which the microphone moves. After giving the adequate delay time, the power spectrum and the cross spectrum are computed, and the power spectrum of the incident sound from the specified direction is estimated. The directivity can be made sharper with increasing the length of the span of the moving microphone. This system is applicable to the case of many sound sources. The validity of this system is proved not only by the digital simulation but also by the experiment conducted in an anechoic chamber抄録全体を表示PDF形式でダウンロード (550K) -
高橋 大弍, 古江 嘉弘, 松浦 邦男原稿種別: 本文
1979 年 35 巻 6 号 p. 314-321
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーVibrations of a homogeneous and isotropic single elastic plate driven by a spherical sound wave and the sound transmission through it, are investigated theoretically by means of the classical thin plate theory. A plate of infinite extent and a finite circular plate, on the normal central axis of which a sound source is located, are studied. For the former, comparison between the effects of plane wave incidence and spherical one is made, and for the later, using the distance from the origin of the central axis to the sound source as a parameter, vibrating plate profiles and transmission characteristics are presented. As a result, it is found that the flexural wave is caused more easily and the sound is radiated from the plate more efficiently with decrease of the distance between the sound source and the plate, i. e. , with increase of the spherical influence of the incident wave.抄録全体を表示PDF形式でダウンロード (855K) -
須山 栄蔵, 平田 賢原稿種別: 本文
1979 年 35 巻 6 号 p. 322-332
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーIt is difficult to suppress the resonance of low frequency range in a silencing system. In order to forecast the necessary attenuation for a silencing system from the standpoint of optimization, the attenuation at each frequency in the muffler is increased until the resonance in the silencing system becomes unresonance, and the amount of attenuation is obtained by the non-dimensional attenuation coefficient η which is the product of the attenuation constant δ in the muffler and its length l. The necessary attenuation coefficient η for the silencing systems is calculated by the general equation obtained from insertion loss formulas. Calculated values of the necessary attenuation coefficient η are compared with theoretical insertion loss of silencing systems, and they are confirmed to be in good agreement. The maximum values of the necessary attenuation coefficient η in the evaluating frequency range for some silencing systems are assumed as the evaluating value η_<max>, and the η_<max> values for all positions of the muffler are calculated, then the optimum position to be set can be selected out of them. Calculated values η_<max> for the silencing systems are compared with the theoretical calculating value of insertion loss for some typical setting position of muffler, and they are confirmed to be in good agreement. From those results, the following facts are confirmed that the attenuation characteristics of the muffler itself necessary for suppressing the resonance and forecast from the non-dimensional necessary attenuation coefficient η, and that the optimum position of the muffler in a silencing system is forecast by the non-dimensional evaluating value η_<max>.抄録全体を表示PDF形式でダウンロード (975K) -
大家 左門, 竹内 龍一原稿種別: 本文
1979 年 35 巻 6 号 p. 333-341
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーIt is well known that application of porous materials on the bare panel improves the ability of sound insulation of the partition. Beranek and others analyzed the sound insulation characteristics of the similar structure based on the assumptions that the mechanical contracts between the bare panel and the porous materials are negligible and that the porous materials are rested. But these assumptions are unrealistic when the porous materials are directly mounted on the panel and they vibrate at the same velocity with each other. In this paper, we analyze the sound insulation or absorption characteristics of this composite structure based on the assumption that the basic panel and the porous materials vibrate at the same velocity with each other, by taking account of the interaction between the solid frame of vibrating porous material and the surrounding fluid. We make some discussions on the increases of transmission loss by the application of the porous materials on the plate and the reciprocal characteristics of the transmission loss.抄録全体を表示PDF形式でダウンロード (1051K) -
佐々木 実原稿種別: 本文
1979 年 35 巻 6 号 p. 342-349
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーThe probability density function and the transition probability density function of sound levels at the site near a road, are derived. These functions can be derived on the basis of the fact that the relation between the traffic volumes and the sound levels seems to be approximately linear in the case when the ratio of distance l between a observation point and a road to the vehicle spacing d, is in the region of 0. 46<l/d<1. 60. The transition matrix of frequencies with which the sound level L_2 dB will be observed just after L_1 dB is observed, is obtained from these functions, and the calculated values are in good agreement with the mesuared ones.抄録全体を表示PDF形式でダウンロード (818K) -
太田 光雄, 山口 静馬, 吉野 信行原稿種別: 本文
1979 年 35 巻 6 号 p. 350-355
発行日: 1979/06/01
公開日: 2017/06/02
ジャーナル フリーPDF形式でダウンロード (724K)
- |<
- <
- 1
- >
- >|