Acoustical Science and Technology

Ultrasound technology that delivers a powerful sound wave with sharp directivity over a long distance in the air is required. As a sound source for this purpose, authors devised an ultrasonic sound source with a new shape in which the opening area is smaller than that of the complex reflective plate, and a reflective plate whose size is equivalent to the area of the vibrating plate was mounted to it. This reflective plate is composed of a planar reflective plate and a truncated cone-shaped reflective plate. In this study, first, the directional characteristics of a circular transverse vibrating plate-type aerial ultrasonic sound source with an integrated rigid wall structure were examined. Next, the planar reflective plate and truncated cone-shaped reflective plate were analyzed to refine the design. Furthermore, a sound source equipped with these reflective plates was fabricated, and various acoustic characteristics were investigated. As the results, when the input power of the sound source was 30 W, the sound pressure was 293 Pa at the distance of 2 m. This is a unidirectional sound wave with a very intense sound pressure.

Shinnosuke Uchiyama

Takuya Asami

Hikaru Miura

Nippon Onkyo Gakkaishi/Acoustical science and technology/Nihon Onkyo Gakkaishi

Acoust. Sci. &amp; Tech.

Development of an aerial ultrasonic sound source with a truncated cone-shaped reflective plate on a circular transverse vibrating plate

圆截锥形反射板圆形横向振动板空中超声声源的研制

Mariko Akutsu

Toki Uda

Yasuhiro Oikawa

Sound wave propagation in the boundary layer around moving source

运动源周围边界层中的声波传播

Tsumugi Nakayama

Shunsuke Kouda

Takatoshi Yokota

Application of machine learning in aircraft noise monitoring: Determining disturbance sounds within aircraft noise events

机器学习在飞机噪声监测中的应用：确定飞机噪声事件中的干扰声音

Two finite element models have recently been utilized to predict the sound absorption coefficient of periodically arranged slit resonators. One is based on the linearized Navier–Stokes equation, entropy conservation law, and mass conservation law. The other is based on the Helmholtz equation with the visco-thermal boundary layer boundary condition. This paper clarifies a condition under which the latter model gives a reasonable approximation. A transition frequency is derived from Johnson–Allard's effective density of porous media as a criterion. Calculation results demonstrate that the resonator's resonance frequency must be higher than the transition frequency to obtain a reasonable prediction using the boundary condition model.

Mio Yonezawa

Naohisa Inoue

Comparison of finite element models for predicting sound absorption coefficients of infinitely periodical slit resonators

有限周期性狭缝谐振器声吸收系数预测的有限元模型比较

Currently, there are three mainstream audio representations, namely channel-based audio, object-based audio, and scene-based audio. The features of content expression differ among these audio representations, the details of which have been specified in the International Telecommunication Union: Radiocommunication Sector (ITU-R) Recommendations. The effective use of these audio representations in accordance with what is to be expressed in the content requires a deep understanding of the technical specifications and capabilities of the audio representations. This review first traces the evolution of loudspeaker layouts developed in recent years, i.e., a history of multichannelization, which is indispensable for the understanding of audio representations. Then, the position of each audio representation among various audio-related standards is described and the method of adopting and implementing each audio representation in other audio-related standards is reviewed using the Moving Picture Experts Group (MPEG) standards as examples.

Takehiro Sugimoto

Specification of audio representations in audio-related standards

音频相关标准中音频表示的规范

Comparison of finite element models for predicting sound absorption coefficients of infinitely periodical slit resonators, [Acoustical Science and Technology 45(6), 324-328 (2024)]

有限元模型预测无限周期狭缝谐振器吸声系数的比较研究，[声学科学与技术 45(6), 324-328 (2024)]

An acoustic metasurface (AMS) can provide high broadband sound absorption realized by planar periodic array assembly of small Helmholtz resonators tuned at different resonant frequencies. The formulation for the sound absorption coefficient of the AMS developed in a previous study provides a uniform and nearly perfect sound absorption in the one octave band. Numerical case studies suggest that the area ratio of the unit cell assembly for the broadband perfect sound absorption of the AMS can be formulated as a power function of frequency ratio to the center frequency and that the formulation will be identical for any center frequency.

Shinsuke Nakanishi

A study on the optimized area ratio of unit cell assembly for the broadband perfect sound absorption of acoustic metasurface

声学超表面宽带完美吸声单元胞组装优化面积比研究

Through three-dimensional wave-based numerical analysis, the propagation characteristics of road traffic noise from embankment roads were investigated, focusing on the effects of the side slope angle and height of the embankment. When the prediction plane was set as an orthogonal cross-section in the lane direction, the distribution of A-weighted sound pressure level differences between embankments with a slope and a right-angle wedge showed relatively high values in the region corresponding to the paths where diffracted sound from the edge of the embankment reflects off the ground surface, regardless of the embankment height, slope angle, and position of the prediction plane. When the embankment height and slope angle were the same, the level difference distribution was nearly the same regardless of the position of the sound source and orthogonal prediction plane. Based on these characteristics, an empirical correction formula was proposed, applicable to an arbitrary orthogonal cross-section to the embankment lane direction, representing the effect of the embankment slope angle in terms of the A-weighted sound pressure level difference. By appropriately setting the values of the coefficients required in the formula, both the maximum and average errors in the prediction plane can be reduced without significantly amplifying either of them.

Yosuke Yasuda

Seiya Nishimura

Yu Kamiya

Makoto Morinaga

Three-dimensional numerical investigation on propagation characteristics of road traffic noise from an embankment road: Construction of correction formula for the effect of side slope angle

堤路交通噪声传播特性的三维数值研究：侧坡角度影响修正公式的构建

Abbreviation	Acoust. Sci. & Tech.
Journal Impact	0.74
Quartiles(Global)	ACOUSTICS(Q4)

ISSN	1346-3969, 1347-5177, 2186-859X
h-index	43

Publication Information	Publisher: Acoustical Society of Japan，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 2000，Proportion of original research papers: 100.00%，Self Citation Rate:16.70%， Gold OA Rate: 92.86%

Acoustical Science and Technology

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Development of an aerial ultrasonic sound source with a truncated cone-shaped reflective plate on a circular transverse vibrating plate

Sound wave propagation in the boundary layer around moving source

Application of machine learning in aircraft noise monitoring: Determining disturbance sounds within aircraft noise events

Comparison of finite element models for predicting sound absorption coefficients of infinitely periodical slit resonators

Specification of audio representations in audio-related standards

Comparison of finite element models for predicting sound absorption coefficients of infinitely periodical slit resonators, [Acoustical Science and Technology 45(6), 324-328 (2024)]

Specification of audio representations in audio-related standards

A study on the optimized area ratio of unit cell assembly for the broadband perfect sound absorption of acoustic metasurface

Comparison of finite element models for predicting sound absorption coefficients of infinitely periodical slit resonators

Three-dimensional numerical investigation on propagation characteristics of road traffic noise from an embankment road: Construction of correction formula for the effect of side slope angle