共查询到19条相似文献,搜索用时 93 毫秒
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室内乐厅是以演奏室内乐为主、兼供独奏(唱)、音乐讲座、文娱演出和立体电影所用的多功能厅堂。为使各项功能均具有最佳的声学条件,设置了用计算机调控混响时间的装置。本文概要介绍室内乐厅的声学设计、但侧重于计算机调控混响时间所取得的成效。 相似文献
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为测量混响时间,按照传统的方法,让声源辐射出稳态噪声讯号,当室内声场到达稳定状态后,把讯号切断,此时测点的传声器拾取在衰减的讯号,经过放大和滤波,在记录仪上划出衰减曲线,然后根据曲线的斜率读出混响时间.这种测量方法,在整理数据时要化费的时间比较多,而且对于判断衰减曲线的斜率,容易出现人为误差. 最近丹麦B&K厂生产一种4417型建筑声 相似文献
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混响是室内声学中的重要现象,在室内设计与音频信号处理中都需要测量或估计混响时间。本文改进了一种基于最大似然估计的混响时间盲估计方法,即采用说话人在房间中自然说话时发出的混响语音信号来估计混响时间的方法。该方法首先确定语音衰减段的最优边界,其次计算该衰减段的两个额外参数,据此筛选出符合条件的语音段,最后将满足条件的语音段采用最大似然估计得到混响时间估计值。在五个不同混响时间条件下的仿真表明,与已有方法相比,改进方法估计的混响时间同真实混响时间的偏差更小,方差更低,估计准确性较高。 相似文献
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本文首先论述厅堂声场控制的各种方法,然后利用混响反馈法和卷积法分别进行了实验研究,其中着重对卷积法的实验系统进行阐述,指出卷积法具有混响时间调节方便、控制范围大等优点,混响时间可提高三倍以上. 相似文献
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混响场时域信号序列的数值实现对主动声纳目标模拟器研制具有重要意义。本文所述适用于水平变化浅海环境混响时间序列的一种实现方法,基于现有的浅海简正波相干混响理论。所述方法的思路是通过相干散射场随机序列与发射信号的离散卷积来构成混响时域序列,文中以Pekeris均匀浅海环境为例,给出了相应的混响时间序列仿真结果,并对仿真结果的频谱特性、统计特性、强度衰减以及垂直相关特性等进行了系统检验。结果表明,由仿真混响时间序列所获得的混响特性与理论结果相符,可用于浅海混响序列的仿真。 相似文献
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I.IntroductionUndcrwatersoundrevcrberationhasrccentlybecomeatopicofgreatinterestlI-3l.Sincethcrcverberationincludescombincdeffcctsofsoundpropagahonandscattering,andthesoundpropagationinshallowwaterismuchmorecomplicatedthanthatinthedeepsea,itisnecessarytOstudycarefullybothintheoryandexperimcnt.Fortheshortrangereverberationinshal1owwatcrtheray-basedmodelisavai1ab1e,whilefOr1ongrangethewave-basedmodelmustbeusedbecauscofcomp1icatcdmu1tipaths,refractioneffcctsandfrequencydependence.Thenorma1-mode… 相似文献
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为揭示深海多途传播效应及界面参数对本地界面混响强度的影响规律,将界面混响表述为不同多途混响衰落过程的非相干叠加结果,并结合界面散射的若干物理机制,建立了以海面海底物理参数为变量的混响强度模型.通过数值仿真和理论分析研究了不同多途混响强度的衰落特性、到达角的空间分布及部分物理参数对混响强度的影响,并利用南海海盆(典型泥质海底)实验数据对模型有效性进行验证.仿真结果表明,界面混响强度随时间变化呈现多峰结构,峰值时间与多途混响的到达时间分布一致。声源与接收器均位于近海面处时,首峰的峰值强度及其衰落过程由海面风速决定,其它峰的峰值强度由海面海底参数共同决定,但其衰落过程主要受到底质参数的影响. 相似文献
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提出一种结合卷积神经网络的编解码器模型和混响时间注意力机制的混响抑制算法,该算法通过编解码器模型实现混响抑制,并利用混响时间注意力机制克服混响环境变化对混响抑制效果的影响。该算法在编码器中使用具有不同大小的卷积核来处理混响语音幅度谱,从而获得包含多尺度上下文信息的编码特征;通过引入注意力模块,实现在不同的混响时间环境中选择性地使用不同权重的编码特征生成加权特征;最后,在解码器中使用加权特征来重建混响抑制后的语音信号幅度谱。在模拟和真实的混响环境下,该算法相对于基线系统在语音混响调制能量比上分别取得了0.36 dB和0.66 dB的提升。实验结果表明,该算法可以适应不同混响环境的变化,相对基线系统在真实混响环境下具有更高的鲁棒性。 相似文献
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The question of what is the optimal reverberation time for speech intelligibility in an occupied classroom has been studied recently in two different ways, with contradictory results. Experiments have been performed under various conditions of speech-signal to background-noise level difference and reverberation time, finding an optimal reverberation time of zero. Theoretical predictions of appropriate speech-intelligibility metrics, based on diffuse-field theory, found nonzero optimal reverberation times. These two contradictory results are explained by the different ways in which the two methods account for background noise, both of which are unrealistic. To obtain more realistic and accurate predictions, noise sources inside the classroom are considered. A more realistic treatment of noise is incorporated into diffuse-field theory by considering both speech and noise sources and the effects of reverberation on their steady-state levels. The model shows that the optimal reverberation time is zero when the speech source is closer to the listener than the noise source, and nonzero when the noise source is closer than the speech source. Diffuse-field theory is used to determine optimal reverberation times in unoccupied classrooms given optimal values for the occupied classroom. Resulting times can be as high as several seconds in large classrooms; in some cases, optimal values are unachievable, because the occupants contribute too much absorption. 相似文献
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Metallic plates are used in recording studios to create artificial reverberation. In this paper, the flexural vibrations of such plates are analysed in order to better understand the influence of geometry and materials on the quality of plate reverberation. A comparison is made with acoustic reverberation, both in the time and frequency domain. This comparison is supported by objective criteria such as modal density and density of reflections. From a physical point of view, the internal and external damping mechanisms are examined in detail since they determine the frequency dependence of the reverberation time. Theoretical results are validated through comparison with experiments performed on an EMT140 reverberation plate. The underlying model is aimed at developing numerical simulations of plates (virtual reverberators) allowing a large variety of reverberations based on variations of geometry and materials as input parameters. 相似文献
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浅海波导中水平接收阵被动时反混响抑制方法研究 总被引:2,自引:0,他引:2
使用基于射线简正波异地混响理论建立的水平接收阵接收海底混响模型,提出了水平阵被动时反混响抑制方法。以水平接收阵接收回波信号的某一时刻作为开始,分别对其前一时刻和后一时刻的回波信号做时反算子分解获得两个混响子空间,将这两个混响子空间的平均作为该时刻的混响子空间的一个估计,然后利用投影处理来抑制该时刻接收信号中的混响成分。该方法可以在一定程度上克服由于海底粗糙引起的局部时间(距离)段内接收回波信号的不平稳性,使得估计得到的混响子空间更加接近真实混响子空间。因此,利用其进行被动时反混响抑制可以增强回波信混比,提高对目标的检测和方位估计能力。针对典型浅海波导环境开展的仿真验证了本文方法的有效性。 相似文献
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K.W. Yeow 《Journal of sound and vibration》1979,67(2):219-229
A theory of external reverberation in urban built-up environments is developed, based on a classical room acoustical model. In the model, external reverberation is analyzed as a special limiting case of internal reverberation in rooms. Explicit formulae are deduced for the statistical value of the external reverberation time, and the spatial distribution of the external sound field amplitude with distance from a fixed, constant power, sound source, for which comparison with published experimental results is possible. Predictions of the theory compare reasonably well with the experimental values. It is found that the external reverberation time in a built-up area depends chiefly on the average building height, and to a lesser extent on the packing fraction, and the ratio of surface area to cross-sectional area of buildings which make up the built-up environment, apart from the absorptive properties of the building and ground plane surfaces. For the spatial distribution of the steady state sound field amplitude in a built-up environment, it is found that the diffuse field amplitude attenuates with distance from a fixed, constant power source exponentially faster than the inverse square law. 相似文献