Feature-based Representation for Violin Bridge Admittances

TL;DR

This paper introduces a novel feature-based method to quantify and compare violin bridge admittances, enabling better analysis of vibrational properties and stylistic similarities in both simulations and real instruments.

Contribution

It presents a new approach to separate frequency, amplitude, and quality factor effects in FRFs, allowing for quantitative comparison and clustering of violin bridge admittances.

Findings

The proposed distance metric effectively distinguishes vibrational differences in simulated data.

It reveals stylistic similarities and differences among real violins.

The method enhances understanding of vibrational properties in musical instrument research.

Abstract

Frequency Response Functions (FRFs) are one of the cornerstones of musical acoustic experimental research. They describe the way in which musical instruments vibrate in a wide range of frequencies and are used to predict and understand the acoustic differences between them. In the specific case of stringed musical instruments such as violins, FRFs evaluated at the bridge are known to capture the overall body vibration. These indicators, also called bridge admittances, are widely used in the literature for comparative analyses. However, due to their complex structure they are rather difficult to quantitatively compare and study. In this manuscript we present a way to quantify differences between FRFs, in particular violin bridge admittances, that separates the effects in frequency, amplitude and quality factor of the first resonance peaks characterizing the responses. This approach allows us to define a distance between FRFs and clusterise measurements according to this distance. We use two case studies, one based on Finite Element Analysis and another exploiting measurements on real violins, to prove the effectiveness of such representation. In particular, for simulated bridge admittances the proposed distance is able to highlight the different impact of consecutive simulation `steps' on specific vibrational properties and, for real violins, gives a first insight on similar styles of making, as well as opposite ones.