Modal analysis of a violin octet

Abstract

Experimental modal analysis of a complete Hutchins-Schelleng violin octet, combined with cavity mode analysis and room-averaged acoustic analysis, gives a highly detailed characterization of the dynamics for this historic group of instruments. All the "signature" modes in the open string pitch region--cavity modes A0 ("main air") and A1 (lowest longitudinal), C-bout "rhomboid," the first corpus bending modes B1- and B1+ (comprising the "main wood")--were observed across the octet. A0 was always the lowest dominant radiator, below all corpus modes. A1 contributed significant acoustic output only for larger instruments, but was the dominant contributor for the large bass in the "main wood" region. Acoustic results indicate either B1- or B1+ can be the major radiator. Damping results indicate that B1 modes overall radiate approximately 28% of their vibrational energy. "Doublet" B1 modes from substructure couplings were observed for three instruments. "A0-B0" coupling was not significant for the largest instruments. The original flat-plate-based scaling of the "main wood" resonance was generally successful across the octet, although that for the "main air" was not.

Modal Parameters of Two Violins with Different Varnish Layers and Subjective Evaluation of Their Sound Quality

“…For unvarnished ("white") and varnished instruments, the mode shapes, modal frequencies, and modal damping of the modes under consideration were similar to those described in earlier papers (Marshall, 1985;Bissinger, 2003;2008;Schleske, 2002). While comparing the modal frequencies of the unvarnished violins the only significant difference was found for mode B(1−), Table 3.…”

“…The mode shape sequence was similar to that well described in earlier papers and analyzed in a descriptive manner, being a widely accepted standard in the literature (Marshall, 1985;Dünnwald, 1999;Bissinger, 1995;2003 (Bissinger, 2008) of the top plate. These modes fall into the first Dünnwald frequency band (190-650 Hz) and are responsible for the sound "richness" (Dünnwald, 1999).…”

“…Among those former, the most popular are optical measurements and modal analysis. A detailed modal analysis of a violin was done by Marshall (1985) and many others (Bissinger, 1995(Bissinger, , 2003(Bissinger, , 2008Bissinger, Keiffer, 2003;Skrodzka et al, 2009). However, a few reports were published on the effect of structural modifications on vibrational behaviour of violins, among them by Weinreich et al (2000), examining a violin with holes drilled in the ribs, and the report by Meinel (1937), who measured the response curves for violins with and without varnish, with thick, normal, and thin plates.…”

“…Modal analysis technique has been extensively used to investigate a behaviour of particular elements of cellos, violins, and guitars, like a cello tailpiece (Fouilhe et al, 2011), the violin bridge, and a soundpost (Bissinger, 1995;2006 (Bissinger, 2003), complete violins (Marshall, 1985;Dünnwald, 1999), and many others.…”

Modelling of Material Parameter Uncertainty of Resonance Wood Used in Violins Using the Interval Field

“…The chain between violin body characteristics and sound production is notoriously hard to model accurately and has been subject of much research already, including work on bridge and snare mobility ( [1,2]), analysis of damping factors ( [4,5]) and modal characterisation of complete string instruments ( [7,6]) Earlier work on characterising the mechanics of the violin body already showed that not some structural modes are more effective at radiating sound than others ( [3]). The effectiveness of a mode can be characterized in two ways:…”