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声波在液体、气体和固体中以纵波的形式向四周传播.当置于空气中的发声体振动时,造成了周围空气的被压缩,使空气形成了周期性的疏密状态变化,这种疏密状态由发声体向外传播,这就形成了空气中的声波(见图1),并遍布于整个传播波的三维空间中. 相似文献
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利用密闭注射器得到近似真空的环境,设计了简易真空不能传声实验装置.该装置利用同极磁铁相互排斥原理,使发声体悬浮,并将接收声音的装置放在发声系统外部,避免了容器本身传递声音. 相似文献
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中国建筑声学的过去和现在 总被引:2,自引:0,他引:2
中国古代论述声音和乐律的记载可追溯到世纪之前,与建筑声学有关的现象,如共振和混响等亦早有所观察和认识。古代有许多专门讨论音乐的书籍,但没有建筑声学的专著。如今用现代声学技术对一些古建筑的分析,解开了许多长期以来令人迷惑的现象和特征。近代建筑声学在中国的萌芽是三十年代末开始的,直至五十年代以后,由于大规模建设的需要才有了蓬勃的发展。本文旨在综述这一进展及成就。 相似文献
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在澄清嗓音源概念的基础上提出了一种以嗓音源变换函数为基础的声门发声效率估计方法。将嗓音源变换函数定义为声门上声学嗓音源与声门气流体积速度波在频域上的比值。通过精心设计的活体犬喉及人体发声实验分别在不同元音、压紧嗓音、气声、假声和典型喉病变条件下。采用稳态元音发声方式对这一新的声门发声效率估计方法实验研究;并与其他发声效率方法综合比较。结果表明,该方法能消除上声道传输与共鸣作用的影响,能反映不同发声方式的差异;频域平均声门发声效率反映了物理定义上的声门发声效率的变化,而声门基频发声效率的变化与AC/DC比值变化一致。 相似文献
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戏曲演员发声特性是厅堂音质研究的重要基础数据。为研究中国粤剧旦角演员发声特性,在全消声室内以4位花旦、2位青衣和1位老旦为例,针对念白、清唱和语言三种发声方式,在大、中、小三种发声力度下,分析不同旦角演员在0.3 m处的声压级、动态范围和频率特性曲线,探讨发声特性与发声方式、发声内容、发声力度和行当之间的关系。结果显示在相同的发声力度下,声压级由大到小的发声方式依次为清唱、念白和语言;老旦的动态范围最大,其次是青衣和花旦;清唱内容对发声频率特性曲线影响较小,而发声方式和行当影响较大;演员以不同力度发声时各频率特性曲线形状相似。该文的实验结果将为戏曲厅堂音质设计、建筑物隔声设计和电声系统设计提供科学依据。 相似文献
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通过对喉发声机理的物理分析及病变对声喉功能影响的分析,寻找能够客观评价喉发声功能的途径——同步测量发声效率与频域相对谐噪比,将上述两参数结合可较全面地对喉发声功能进行量化评价。 相似文献
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椰胡是具有地方特色的拉弦乐器之一,多用于演奏广东音乐和广东戏曲、曲艺的伴奏。但对其发声强度一直未进行过科学的测试。本文介绍在华南理工大学半消声室内参照ISO(GB)标准对椰胡声功率级的测量工作。由两位资深乐师分别用两把椰胡在pp,mp,f和ff力度下演奏单音、音阶和乐曲,对每一把椰胡的每一测试内容,由十通道测试设备同步测试中心频率为100~10000 Hz的1/3倍频带声压级谱,通过计算获得每把椰胡在演奏每项内容时的声功率级和动态范围。通过对两把椰胡的测试结果进行平均,获得该乐器在演奏上述内容时的典型声功率级数值及频谱。文中并将半消声室内的测试结果与混响室内的测试结果相对比,探讨测试环境对测试结果的影响。民族乐器发声强度及其频谱特性的获得是开展民族音乐厅堂音质研究的基础。 相似文献
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This paper presents an original piece of research using holographic interferometry as a quantitative optical diagnostic. The object under investigation was the soundboard of a harpsichord. The results obtained show that it is possible to measure the spatial vibrational behaviour of the whole soundboard with an accuracy of better than 170 nm. Several features which characterize the vibration behaviour of the soundboard have been visualized including a discontinuity created by a crack which has resulted in a phase change of the interferometric fringes. Finally, the theoretical model response of the harpsichord soundboard is determined and compared to our holographic measurement. 相似文献
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周期性信号基频的检测具有重要的意义,通常的硬件检测方法是采用过零比较器或施密特触发器等电路对输入信号进行整形,从而获得基频脉冲。当信号波形复杂时,这种检测方法就会失准。本文提出了一种新的硬件检测方法有效转变点实时基频检测法,它用两个适当电平切割被测信号,从而获得有效的零点,解决了信号复杂时过零点增多的现象,文内并给出了一个检测人声基频进而实现人声向乐器声转化的应用实例。 相似文献
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筝是中国古老的弹弦乐器。但迄今为止,对其声功率级一直未进行科学的测定。本文在一混响室内根据ISO及GB标准,对二十一弦筝的声功率级进行了首次测定。两位资深乐师在混响室内分别演奏各自的乐器,通过围绕乐师和乐器布置的四通道测试设备,对筝所辐射的声功率级和动态范围进行测定。测试结果表明,中国筝在以不同力度演奏单音、音阶和乐曲时所辐射的声功率级及其频率特性均有所不同。考虑到乐器演奏音阶时所辐射的声功率级及其动态范围与演奏乐曲时的声功率级接近,并且,音乐的空间感也大都在乐器以f力度演奏乐曲的强音标志乐段时最为显著,故此我们建议中国筝所辐射的声功率级用其以f力度演奏音阶时的平均声功率级表示。本文测试的两架中国筝以f力度演奏音阶时的平均声功率级为85.9dB。文中不仅首次公布了中国筝声功率级的测试结果,并且所介绍的测试方法对其它乐器声功率级测试也具有借鉴意义。民族乐器所辐射的声音性能的确定是民族音乐厅堂音质研究的基础。 相似文献
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In this article, a system that takes a 3D model of a sculpture as starting point to compose music is presented. We raised the hypothesis that cross-domain mapping can be an approach to model inspiration. The semantic meaning of the sculpture is not used directly but rather a more abstract approach was used. A Genetic Algorithm was used to obtain results with more musical interest. The results were promising: the majority of the participants gave a classification of 4 out of 5 to the preferred interpretations of the compositions and related them to the respective sculpture. This is a step toward a possible model for inspiration. 相似文献
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E.P. Borges 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):593-595
Comment on Eur. Phys. J. B 27, 445 (2002)
We analyze the distribution of success of musicians, comparing a stretched exponential (found by J.A. Davies [Eur. Phys.
J. B 27, 445 (2002)]) with a distribution of the family of the q-exponential (presenting an intermediate power-law regime with a crossover to an exponential tail). We find that both assumptions
yield comparable results, within the available range of data, hence a definite conclusion cannot yet be taken. But this example
joins many others that has been found to be fairly described by q-exponentials (or variations of it), which may be indicative that there is a (significantly large) class of systems described
by nonextensive statistical mechanics, from where q-exponentials naturally appear.
Received 17 October 2002 Published online 31 December 2002 相似文献
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J.A. Davies 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(4):445-447
Over the last five years or so, a number of studies have focussed on the distribution of `success' in physics and other sciences;
in these studies, `success' is measured by the number of times a paper, or an author, is cited. The distribution of citations
of individual papers approximates to a power-law [S. Redner, Eur. Phys. J. B 4, 131 (1998)], while lifetime total citations of the 1120 most-cited physicists follows a stretched exponential [J. Laherrère,
D. Sornette, Eur. Phys. J. B 2, 525 (1998)]. Here, I examine the distribution of success in popular music, a field of creativity that has social structures
very different from those of physics, and which is generally held to be controlled primarily by fashion. For this study, the
lifetime total success of bands was measured by the total number of weeks they were in the weekly `top 75' list of best-selling
recordings. Like the lifetime success of physicists reported by Laherrere and Sornette, the success of the 6107 bands that
appeared in the UK `top 75' from 1950 until 2000 follows a stretched exponential of the form P(x)dx = c(x
c - 1/x
0
c)exp[- (x/x
0)c]dx; for the music data, c = 0.5 and x
0 = 9.37.
Received 23 October 2001 Published online 25 June 2002 相似文献