• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied Acoustics >Reverberation time measurements in non-diffuse acoustic field by the modal reverberation time
【24h】

Reverberation time measurements in non-diffuse acoustic field by the modal reverberation time

机译：用模态混响时间测量非扩散声场中的混响时间

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The increasing presence of low frequency sources and the lack of acoustic standard measurement procedures make the extension of reverberation time measurements to frequencies below 100 Hz necessary. In typical ordinary rooms with volumes between 30 m(3) and 200 m(3) the sound field is non-diffuse at such low frequencies, entailing inhomogeneities in space and frequency domains. Presence of standing waves is also the main cause of bad quality of listening in terms of clarity and rumble effects. Since standard measurements according to ISO 3382 fail to achieve accurate and precise values in third octave bands due to non-linear decays caused by room modes, a new approach based on reverberation time measurements of single resonant frequencies (the modal reverberation time) has been introduced. From background theory, due to the intrinsic relation between modal decays and half bandwidth of resonant frequencies, two measurement methods have been proposed together with proper measurement procedures: a direct method based on interrupted source signal method, and an indirect method based on half bandwidth measurements. With microphones placed at corners of rectangular rooms in order to detect all modes and maximize SNRs, different source signals were tested. Anti-resonant sine waves and sweep signal turned out to be the most suitable for direct and indirect measurement methods respectively. From spatial measurements in an empty rectangular test room, comparison between direct and indirect methods showed good and significant agreements. This is the first experimental validation of the relation between resonant half bandwidth and modal reverberation time. Furthermore, comparisons between means and standard deviations of modal reverberation times and standard reverberation times in third octave bands confirm the inadequacy of standard procedure to get accurate and precise values at low frequencies with respect to the modal approach. Modal reverberation time measurements applied to furnished ordinary rooms confirm previous results in the limit of modal sound field: for highly damped modes due to furniture or acoustic treatment, the indirect method is not applicable due to strong suppression of modes and the consequent deviation of the acoustic field from a non-diffuse condition to a damped modal condition, while standard reverberation times align with direct method values. In the future, further investigations will be necessary in different rooms to improve uncertainty evaluation. (C) 2016 Elsevier Ltd. All rights reserved.
机译：越来越多的低频源和缺乏声学标准测量程序，使得混响时间测量必须扩展到100 Hz以下的频率。在体积介于30 m（3）和200 m（3）之间的典型普通房间中，声场在如此低的频率下不会扩散，这会导致空间和频域的不均匀性。就清晰度和隆隆声而言，驻波的存在也是导致收听质量下降的主要原因。由于归因于房间模式引起的非线性衰减，因此根据ISO 3382的标准测量无法在第三倍频程中获得准确和精确的值，因此引入了一种基于单个共振频率的混响时间测量（模态混响时间）的新方法。从背景理论出发，由于模态衰减与谐振频率半带宽之间的内在联系，提出了两种测量方法以及适当的测量程序：基于中断源信号法的直接方法和基于半带宽测量的间接方法。将麦克风放在矩形房间的角落，以便检测所有模式并最大化SNR，测试了不同的源信号。反共振正弦波和扫描信号被证明分别最适合直接和间接测量方法。通过在一个空的矩形测试室中进行空间测量，直接方法和间接方法之间的比较显示出良好而重要的一致性。这是共振半带宽与模态混响时间之间关系的首次实验验证。此外，模态混响时间的平均值与标准偏差之间的比较以及第三八度音阶中的标准混响时间，证实了标准程序不足以针对模态方法在低频获得准确的数值。应用于带家具的普通房间的模态混响时间测量证实了模态声场极限的先前结果：由于家具或声学处理而导致的高阻尼模态，由于对模态的强烈抑制以及随之而来的声学偏移，间接方法不适用范围从非扩散条件到阻尼模态条件，而标准混响时间与直接方法值一致。将来，有必要在不同的房间进行进一步的调查，以改善不确定性评估。 （C）2016 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号