Development of techniques for visualization and auralization of sound and vibration for acoustic research and education

本研究针对环境声学的研究与教育，探讨了各种不能直接看到或听到的声学与振动现象的可视化与可听化方法。(1)通过物理实验可视化波动现象为了可视化各种波动现象，采用波纹水槽法研究了声屏障上的声衍射和声在不同形状房间中的传播。作为物理实验的第二种方法，利用Kundt实验对声管中的简正模、封闭管道中的声共振以及Helmholtz共振器中的声共振进行了可视化实验。实验设施已经完善，用于声学教育示范。通过应用这种实验技术，对汽车轮胎花纹中的声共振现象进行了研究， ...更多信息 在具有各种形状的二维空间中的所有模式和客车被可视化。(2)基于时域有限差分法的波动数值分析技术，将声共振和声衍射等基本声学现象可视化和可听化。作为一种声学教学工具，这种模拟技术被命名为“数值消声室”，并已开发出实用软件。(3)用于各种声场可听化的三维声场再现系统在诸如室内声学和环境噪声评估的实验研究中，期望在实验室中再现具有三维声学信息的被调查声场。作为实现这一条件的技术，本研究应用了“6通道记录/再现技术，并通过开发新的麦克风系统和再现系统来改善其模拟性能。其结果是，一个相当高的性能的声源定位已实现和精确的三维声场模拟已成为可能。该技术已应用于以下主观实验：1）音乐演奏者在音乐厅舞台上的声学条件，2）机动车辆中的声学舒适性（行驶噪声的烦恼度和汽车音响系统的易听性），以及3）交通噪声的嘈杂度评估（道路交通噪声、飞机噪声、新干线超高速列车和常规铁路列车）具有多种时间变化特征。少

In this study, the methods for visualization and auralization of various kinds of acoustic and vibration phenomena which can not be directly seen or heard have been investigated for the research and education in environmental acoustics.(1) Visualization of wave phenomena by physical experimentsTo visualize various kinds of wave phenomenena, sound diffraction over acoustic barriers and sound propagation in rooms with various shapes were investigated using the ripple-tank method. The results of these experiments were compared with the results obtained by numerical simulation based on FDTD methods.As the second method for physical experiment, the Kundt experiment was applied to visualize the normal modes in an acoustic tube and acoustic resonance in a closed pipe and a Helmholtz resonator. The experimental facilities have been refined for demonstration for acoustic education. By applying this experimental technique, acoustic resonance in the tread-patterns of a motor-vehicle tire and norm … More al modes in two dimensional spaces with various shapes and a passenger car were visualized.(2) Visualization and auralization of wave phenomena by numerical analyses using computerSuch basis acoustic phenomena as acoustic resonance and sound diffraction were visualized and auralized by the wave numerical analysis technique based on the FDTD method. As a tool for acoustic education, this simulation technique was named "numerical anechoic room" and its practical software has been developed.(3) 3-D sound field reproduction system for auralization of various kinds of sound fieldsIn such experimental researches as room acoustics and assessment of environmental noises, it is desirable to reproduce the sound fields under investigation in the laboratory with 3-dimensional acoustic information. As a technique to realize this condition, the "6-channel recording/reproduction technique was applied and its simulation performance has been improved in this study by developing a new microphone system and the reproduction system. As a result, a considerably high performance of sound source localization has been realized and precise 3-D sound field simulation has become possible. This technique has been applied to the following subjective experiments : 1) acoustic conditions on the stage of a concert hall for music players, 2) acoustic comfortableness in motor-vehicles (annoyance of running noise and easiness of listening to car-audio system), and 3) assessment of noisiness of traffic noises (road traffic noise, aircraft noise, Shinkansen super-express train and conventional railway train) with a variety of temporal variation characteristics. Less