The evolution of air resonance power efficiency in the violin and its ancestors

Abstract

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.

Acoustic evolution of old Italian violins from Amati to Stradivari

“…Nia et al have recently reported that the f-holes gradually lengthened going from Amati to Stradivari violin models. Based on computer simulation, they predicted the air resonance mode of Stradivari violins to carry higher frequency and greater power ( 6 ). Our data demonstrate that Strad violins also produce higher F1 to F4 formants than other old Italian violins.…”

“…Among the old masters, Stradivari’s instruments are the most preferred by modern soloists, and his models are also the most copied by modern makers. Construction differences between Amati and Stradivari violins have been carefully studied, including plate geometry ( 2 , 4 , 5 ), f-hole design ( 6 ), varnishing methods ( 7 ), and so on. However, the tonal distinctions between Stradivari and Amati violins remain poorly understood.…”

Modeling The Effect of Background Sounds on Human Focus Using Brain Decoding Technology

“…But only up to a point: psychophysical thresholds exist and there are clearly natural laws governing much of the way humans hear and experience sound. 20,21,22 One of the most promising approaches to studying the impact of sound on humans has been combining audio content feature analysis (based on a sound's physical properties), with measures of human experience (such as Self-Assessment Manikin surveys on arousal and valence after listening). 23,24 Using properties of sound as features and experience measures as labels for those features, several groups have attempted to build machine learning algorithms that can predict emotional responses based on the sound properties alone, commonly according to a valence-arousal circumplex model.…”

Banishing the myths and dogmas surrounding the biotech Stradivarius

“…A consensus among experts is that these instruments deliver superior sounds to violins made since the Baroque era, and there have been several hypotheses-both scientifically supported and unsupported ones-attempting to elucidate the cause of such a superior sound quality. Claims range from a mysterious ingredient to the wood, or a secret varnish recipe (Echard et al, 2010;Mancini, Tromba, & Zanini, 2006;Nagyvary, DiVerdi, Owen, & Tolley, 2006;Nia et al, 2015), to the instruments' unique shape and even good old-fashioned genius of the ancient master violinmakers. However, the most convincing evidence relates to the climate at that time, where the "little Ice Age" (Mauder Minimum, 1645-1715 caused European spruces (Picea abies) that form the instruments' top plate to grow regularly, giving the instrument a fuller and more consistent sound (Burckle & Grissino-Mayer, 2003;Stoel & Borman, 2008).Making modern-day bow instruments superior may mean trying to recreate the effect of cold climate on wood, which we managed to achieve with the help of wood-decomposing fungi.…”