The acoustics of a plucked harp string

Woodhouse, J.

doi:10.1016/j.jsv.2021.116669

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…For the higher strings on a harp, the E B values for the synthetic strings were up to three times higher than for the gut strings, which has direct implications for the degree of inharmonicity in the string overtones and their degree of damping [9], and also for the magnitude of phantom partials generated as a non-linear effect of the coupling between the longitudinal and transverse motions of the string, due to the acute angle between the string and the harp soundboard [10].…”

Section: Introductionmentioning

confidence: 93%

Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings

Lynch-Aird

Woodhouse

2023

Materials

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Natural gut harp strings are made from twisted bundles of gut strips, which are dried, ground, and varnished. The effects of varying the twist angle and surface finishing on the mechanical properties of gut harp strings have been explored. Strings were tested over a range of twist angles from 23.5∘ to 58.3∘, and with all four combinations of ground or unground and varnished or unvarnished surface finishing. The principal effects of varying the degree of twisting were that the breaking strength and tensile Young’s modulus both fell as the twist angle was increased. String makers must therefore make a compromise between sound quality and string strength and durability. Leaving the string unvarnished dramatically increased the sensitivity to changes in humidity, which, in turn, affected the thermal tuning sensitivity and creep behaviour. Grinding the string surface prior to varnishing had no significant effect on the behaviour, but did make some difference to the thermal tuning sensitivity if the string was left unvarnished. Increasing the humidity frequently triggered episodes of additional string creep. There appeared to be a threshold effect, with the additional creep triggered when the string linear density exceeded its previous maximum. When the string was not creeping, there appeared to be a strong coupling mechanism between changes in the linear density and complementary changes in the string tension, such that there was almost no net effect on the string frequency. This behaviour was independent of the twist angle and the surface finishing, suggesting that whatever the coupling mechanism was, it was not dependent on the twisted structure of the string.

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Section: Introductionmentioning

confidence: 93%

Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings

Lynch-Aird

Woodhouse

2023

Materials

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“…Longitudinal string vibrations have been shown to strongly influence the sound signature of several instruments 7,25,26 . As a simple approach, a one way coupling of the (pinned-pinned) string polarization Y with the body is included through the application of the longitudinal force, at both string ends, as an external force on the body after proper projection.…”

Section: Approximation Of Longitudinal Polarization's Influencementioning

confidence: 99%

“…The latter highlighted the presence of string-string modes in the complete structure. Another recent study 7 focused on the existence of a characteristic "harp sound" and sought its origins in the unusual physical configuration with respect to other plucked-string instruments. A nonlinear model of string/soundboard coupling allowed to point out the strong influence of the string/soundboard angle on the sound through the excitation of longitudi-nal string vibrations.…”

Section: Introductionmentioning

confidence: 99%

Physical modelling of a harp from Central Africa

Fabre,

Le Carrou,

Chomette

2023

The Journal of the Acoustical Society of America

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Central Africa harps are string instruments, often anthropomorphic, serving an essential cultural role. Compared to pedal harps, their body is small in size with a soundboard mainly made of animal skin and a neck made of a wood beam. In this paper, a physical model is developed as a tool for assessing the specificities of these musical instruments, from a vibro-acoustic perspective. The modeling strategy is based on the modal Udwadia-Kalaba formalism which is a multibody substructuring technique. Input modal parameters of the body and the strings are experimentally identified and the main steps of the estimation procedures are detailed. The reliability of the physical model is investigated via the comparison between simulated and experimental data for several plucking configurations. Different hypotheses are assessed such as the string/neck coupling which proves to strongly influence the dynamic response of the body when there is a coincidence between string and neck modal frequencies. The inclusion of geometrical nonlinearities proves to be of major importance, even for a weak plucking, as it allows qualitative representation of double frequency terms in the simulations. Overall, physical simulations of the soundboard motion are in good agreement with measurements indicating characteristic features of the instrument are captured.

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“…Nevertheless, implementing procedures for this purpose can often be intricate, sometimes requiring a combination of numerical methods with different natures. In the realm of musical instrument acoustics, there are instances of research employing various simulations working collaboratively to analyze the vibrational behavior of plucked and bowed instruments (e.g., [1][2][3]). However, such research endeavors remain relatively scarce, limiting the depth of studies on violin design.…”

Section: Introductionmentioning

confidence: 99%

Differences in violin sounds caused by changes on arching profiles

Torres

2024

Rev. Mex. Fís.

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An experimentally calibrated numerical model was employed to examine the vibroacoustic impact of the arching profile in a violin soundbox, a study unattainable through experimental means alone. The finite element method successfully modeled the soundbox using the material properties of an actual violin, albeit with a simplified representation of the coupling with the air in the cavity and the forces from the strings. Achieving agreement with the real counterpart necessitated careful adjustment of the modal damping in the simulation. Damped models of violins are infrequently encountered. The impulse response of the soundbox model was obtained through the calculation of thousands of substeps induced by forced vibration. To streamline the time-domain analysis, the superimposed method was implemented instead of the more commonly used full option, resulting in a significant reduction in computational time. Additionally, synthetic musical notes, accounting for how the force of the strings is transmitted through the bridge, were employed as input to the soundbox model. Subsequently, the impulse responses were convolved with the synthetic notes to generate sounds. Through these procedures, the violin’s performance was assessed as the height of the arching profile of the plates was adjusted. The results demonstrated that higher arching profiles led to a general increase in the resonant frequencies of the violin, perceptible in the sound generated by the model.

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The acoustics of a plucked harp string

Cited by 6 publications

References 12 publications

Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings

Effects of Twisting and Surface Finish on the Mechanical Properties of Natural Gut Harp Strings

Physical modelling of a harp from Central Africa

Differences in violin sounds caused by changes on arching profiles

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