- 著者
- Hironori Takemoto Seiji Adachi Natsuki Toda
- 出版者
- ACOUSTICAL SOCIETY OF JAPAN
- 雑誌
- Acoustical Science and Technology (ISSN:13463969)
- 巻号頁・発行日
- vol.44, no.1, pp.9-16, 2023-01-01 (Released:2023-01-01)
- 参考文献数
- 15
The vocal tract can be modeled as an acoustic tube in the low-frequency region because the plane wave propagation is dominant. Further, it can be considered static for a limited short period during running speech, such as vowels. Thus, its acoustic properties have been examined mainly using the transmission line model (TLM), that is, the one-dimensional static model in the frequency domain. In the present paper, we propose a one-dimensional static model in the time domain based on the finite-difference time-domain method. In this model, the vocal tract is represented by the cascaded acoustic tubes of different cross-sectional areas. The pressure and wall vibration effects are simulated at the center of each tube. On the other hand, the volume velocity is calculated at the labial end. According to the leapfrog algorithm, the pressure and volume velocity are sequentially computed. As a result, the impulse responses of the vocal tracts for the five Japanese vowels were calculated, and the corresponding transfer functions agreed well with those calculated by the TLM in the low-frequency region. The mean absolute percentage difference of the lower four peaks for the five vowels was 2.3%.
- 著者
- Seiji Adachi
- 出版者
- ACOUSTICAL SOCIETY OF JAPAN
- 雑誌
- Acoustical Science and Technology (ISSN:13463969)
- 巻号頁・発行日
- vol.25, no.6, pp.400-405, 2004 (Released:2004-11-01)
- 参考文献数
- 41
- 被引用文献数
- 4 6
This paper presents an outline of the sound production mechanisms in wind instruments and reviews recent progress in the research on different types of wind instruments, i.e., reed woodwinds, brass, and air-jet driven instruments. Until recently, sound production has been explained by models composed of lumped elements, each of which is often assumed to have only a few degrees of freedom. Although these models have achieved great success in understanding the fundamental properties of the instruments, recent experiments using elaborate methods of measurement, such as visualization, have revealed phenomena that cannot be explained by such models. To advance our understanding, more minute models with a large degree of freedom should be constructed as necessary. The following three different phenomena may be involved in sound production: mechanical oscillation of the reed, fluid dynamics of the airflow, and acoustic resonance of the instrument. Among them, our understanding of fluid dynamics is the most primitive, although it plays a crucial role in linking the sound generator with the acoustic resonator of the instrument. Recent research has also implied that a rigorous treatment of fluid dynamics is necessary for a thorough understanding of the principles of sound production in wind instruments.
- 著者
- Seiji Adachi
- 出版者
- ACOUSTICAL SOCIETY OF JAPAN
- 雑誌
- Acoustical Science and Technology (ISSN:13463969)
- 巻号頁・発行日
- vol.38, no.1, pp.14-22, 2017-01-01 (Released:2017-01-01)
- 参考文献数
- 23
- 被引用文献数
- 2 2
A minimal model explaining intonation anomaly, or pitch sharpening, which can sometimes be found in baroque flutes, recorders, shakuhachis etc. played with cross-fingering, is presented. In this model, two bores above and below an open tone hole are coupled through the hole. This coupled system has two resonance frequencies ω±, which are respectively higher and lower than those of the upper and lower bores ωU and ωL excited independently. The ω± differ even if ωU= ωL. The normal effect of cross-fingering, i.e., pitch flattening, corresponds to excitation of the ω--mode, which occurs when ωL⪆ωU and the admittance peak of the ω--mode is higher than or as high as that of the ω+-mode. Excitation of the ω+-mode yields intonation anomaly. This occurs when ωL⪅ωU and the peak of the ω+-mode becomes sufficiently high. With an extended model having three degrees of freedom, pitch bending of the recorder played with cross-fingering in the second register has been reasonably explained.