Bader Rolf, Fischer Jost, Münster Malte, Kontopidis Patrick
Institute of Systematic Musicology, University of Hamburg, Neue Rabenstrasse 13, 20354 Hamburg, Germany.
J Acoust Soc Am. 2019 May;145(5):3086. doi: 10.1121/1.5102168.
Mechanical musical instruments have a restricted timbre variability compared to electronic instruments. Overcoming this is the aim of extended playing techniques as well as building more sophisticated musical instruments in recent years. Metamaterials might be a way to extend timbre of mechanical instruments way beyond their present sound capabilities. To investigate such possibilities, a frame drum is manipulated to achieve different sounds. On the drum membrane of 40 cm diameter, a ring of masses is attached in three diameters, 8, 10, and 12 cm with 10 masses each, leading to a cloaking behaviour of vibrations from within the ring into the area outside the ring and vice versa, as shown by microphone-array and high-speed laser interferometry measurements. The resulting sounds have a band gap between about 300 and 400 Hz to about 700-800 Hz, depending on the ring diameter. The 8 cm diameter ring shows the strongest amplitude attenuation in the band gap. Still, when striking the membrane outside the ring, it sounds like a regular drum. This leads to a tremendously increased variability of musical articulations, especially when striking in the ring, as a band gap sound cannot be produced by a regular drum.
与电子乐器相比，机械乐器的音色变化有限。克服这一问题是近年来拓展演奏技巧以及制造更复杂乐器的目标。超材料可能是一种将机械乐器音色扩展到远超其当前声音能力的方法。为了研究这种可能性，对一个框架鼓进行了改造以获得不同的声音。在直径40厘米的鼓膜上，在三个直径分别为8厘米、10厘米和12厘米的位置各附着一圈质量块，每个直径位置有10个质量块，这导致了环内振动向环外区域的隐身行为，反之亦然，这通过麦克风阵列和高速激光干涉测量得以证明。根据环的直径，产生的声音在大约300至400赫兹到大约700 - 800赫兹之间有一个带隙。直径8厘米的环在带隙中显示出最强的振幅衰减。然而，当敲击环外的鼓膜时，它听起来仍像普通的鼓。这极大地增加了音乐表现力的变化性，特别是当在环内敲击时，因为普通鼓无法产生带隙声音。
