在消声室环境下测试了三款线阵列扬声器样品的垂直指向性。结果显示中高频段在主瓣以外方向角位置的辐射强度衰减量仅为10 d B或以下,原因是扬声器箱体之间无辐射间隙的栅格干涉效应,形成副极大瓣,其所在的方向角位置与理论计算结果基...在消声室环境下测试了三款线阵列扬声器样品的垂直指向性。结果显示中高频段在主瓣以外方向角位置的辐射强度衰减量仅为10 d B或以下,原因是扬声器箱体之间无辐射间隙的栅格干涉效应,形成副极大瓣,其所在的方向角位置与理论计算结果基本吻合,并且由于扬声器箱体及辐射单元的物理结构限制,辐射面填充率难以进一步提高。展开更多
A theoretical model of ambient sea noise including surface noise sources and stratified medium ocean is discussed. The noise sources are assumed to be statistically independent directional point sources distributed ov...A theoretical model of ambient sea noise including surface noise sources and stratified medium ocean is discussed. The noise sources are assumed to be statistically independent directional point sources distributed over the ocean surface, and the effects of ocean environment on ambient noise are studied. The normal-mode theory of surface-generated noise is developed, and the normal-mode formula of the directional density function suitable for small grazing angles is analytically continued for being suitable for great grazing angles and consistent with the ray formula. The unified formulae for calculating the intensities, spatial correlation and vertical directivity of ambient sea noise are presented.展开更多
测试了一款小型线阵列扬声器进行垂直指向性,比较了圆形扬声器单元安装与不安装相位塞情况下声辐射性能的差异。结果表明,在中低频范围,安装相位塞可有效抑制副极大瓣,增大前方能量辐射比例。但在8 k Hz和10k Hz,副极大瓣则只能在一定...测试了一款小型线阵列扬声器进行垂直指向性,比较了圆形扬声器单元安装与不安装相位塞情况下声辐射性能的差异。结果表明,在中低频范围,安装相位塞可有效抑制副极大瓣,增大前方能量辐射比例。但在8 k Hz和10k Hz,副极大瓣则只能在一定程度上被减弱而无法消除。展开更多
文摘在消声室环境下测试了三款线阵列扬声器样品的垂直指向性。结果显示中高频段在主瓣以外方向角位置的辐射强度衰减量仅为10 d B或以下,原因是扬声器箱体之间无辐射间隙的栅格干涉效应,形成副极大瓣,其所在的方向角位置与理论计算结果基本吻合,并且由于扬声器箱体及辐射单元的物理结构限制,辐射面填充率难以进一步提高。
基金The project supported by National Natural Science Foundation of China
文摘A theoretical model of ambient sea noise including surface noise sources and stratified medium ocean is discussed. The noise sources are assumed to be statistically independent directional point sources distributed over the ocean surface, and the effects of ocean environment on ambient noise are studied. The normal-mode theory of surface-generated noise is developed, and the normal-mode formula of the directional density function suitable for small grazing angles is analytically continued for being suitable for great grazing angles and consistent with the ray formula. The unified formulae for calculating the intensities, spatial correlation and vertical directivity of ambient sea noise are presented.
