看见声音:声音记录成像技术

<正>十九世纪末至二十世纪初的录音资料提供了那个时代有限但是多样的历史记录。随着信息技术时代的来临,传统的生活方式发生了变化或消失。第一代人类学家和语言学家等采用录音记录了那个时代的部分演变。通过录音技术使得我们可以不断重复欣赏以前只能在剧场等地方聆听的声乐表演。这也推动了音乐及相关表演艺术的巨大发展。录音技术的发明者也给我们留下了这种现代技术产生的实验记录、设备和文件。早期的声音记录是世界的宝贵财富。     

现代嗓声科学系列讲座之三(下)——声乐声感知的研究进展

上文(现代嗓声科学系列讲座之三——有关的心理声学。应用声学,8-5(1989),39.)讲了有关的心理声学部分,本文继之讲声乐声感知的研究进展。     

声乐的颤音与调幅波

 当歌星放声歌唱,发出某一音阶的较长乐声时,常常能听到一种音量上有缓慢节律变化的、富有弹性的声音。在声乐中称为颤音(Vibrato)或“揉弦效应”。初学者模拟这种声音时,刻意去调控音量的起伏,却往往发出生硬的抖音,有人戏称为“打摆子”。其实,歌唱家并没有刻意去做作,而是通过科学的发声训练而获得的发音效果。为什么他们能发出如此自然而动听的颤音?唱歌除了要运用好人体中各个部位的共鸣器---如胸腔、腹腔、口腔、鼻腔、鼻窦、额窦等等以获得浑厚、嘹亮的声音外,最重要的发声器官就是一对声带。     

囧版三国之爆竹声声乐翻天

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Acoustic band pinning in the phononic crystal plates of anti-symmetric structure

Acoustic bands are studied numerically for a Lamb wave propagating in an anti-symmetric structure of a one-dimensional periodic plate by using the method of supercell plane-wave expansion. The results show that all the bands are pinned in pairs at the Brillouin zone boundary as long as the anti-symmetry remains and acoustic band gaps (ABGs) only appear between certain bands. In order to reveal the relationship between the band pinning and the anti-symmetry, the method of eigenmode analysis is introduced to calculate the displacement fields of different plate structures. Further, the method of harmony response analysis is employed to calculate the reference spectra to verify the accuracy of numerical calculations of acoustic band map, and both the locations and widths of ABGs in the acoustic band map are in good agreement with those of the reference spectra. The investigations show that the pinning effect is very sensitive to the anti-symmetry of periodic plates, and by introducing different types of breakages, more ABGs or narrow pass bands will appear, which is meaningful in band gap engineering.