The evolution of air resonance power efficiency in the violin and its ancestors
The evolution of air resonance power efficiency in the violin and its ancestors
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DOI：
10.1098/rspa.2014.0905
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发表时间：
2015-03-08
影响因子：
3.5
通讯作者：
Makris, Nicholas C.
中科院分区：
文献类型：
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作者：
Nia, Hadi T.;Jain, Ankita D.;Makris, Nicholas C.
小提琴在空气腔共振时的声辐射是单极的，可以通过纯粹的体积变化来确定，这一事实有助于解释小提琴设计演变的相关方面。通过确定任意形状的声孔的声导，它被发现，在周边，而不是更广泛的声孔面积的空气流占主导地位的声导，和小提琴内的可压缩空气和它的弹性结构之间的耦合降低亥姆霍兹共振频率从发现一个相应的刚性仪器由大约一个hundrone。由于前者，人们发现，随着小提琴祖先的音孔几何形状在几个世纪内从简单的圆形慢慢演变为复杂的f孔，效率低下、声学不活跃的总音孔面积的比例被大幅降低，大约是空气共振功率效率的两倍。两个世纪以来，在Amati、Stradivari和Guarneri的著名工作室中，F孔长度缓慢增加了大约30%，这有利于具有更高空气共振功率的乐器，相应的功率增加了大约60%。通过进化率分析，这些变化被发现是一致的突变范围内产生的意外复制波动的工艺限制与随后的选择有利于仪器具有较高的空气共振功率。
The fact that acoustic radiation from a violin at air-cavity resonance is monopolar and can be determined by pure volume change is used to help explain related aspects of violin design evolution. By determining the acoustic conductance of arbitrarily shaped sound holes, it is found that air flow at the perimeter rather than the broader sound-hole area dominates acoustic conductance, and coupling between compressible air within the violin and its elastic structure lowers the Helmholtz resonance frequency from that found for a corresponding rigid instrument by roughly a semitone. As a result of the former, it is found that as sound-hole geometry of the violin's ancestors slowly evolved over centuries from simple circles to complex f-holes, the ratio of inefficient, acoustically inactive to total sound-hole area was decimated, roughly doubling air-resonance power efficiency. F-hole length then slowly increased by roughly 30% across two centuries in the renowned workshops of Amati, Stradivari and Guarneri, favouring instruments with higher air-resonance power, through a corresponding power increase of roughly 60%. By evolution-rate analysis, these changes are found to be consistent with mutations arising within the range of accidental replication fluctuations from craftsmanship limitations with subsequent selection favouring instruments with higher air-resonance power.