Analysis of the influence of different construction factors of violin mutes on their effects: a methodological prospection based on the controlled variation of physical characteristics of the devices

The article describes prospecting's carried out in ongoing doctoral research that aims to develop new prototypes of violin mutes, relying on the analysis of quantitative data extracted from violin recordings under the effect of different types of mutes. These prospecting's aim to define an adequate analysis methodology to isolate the contributions of specific physical characteristics of mutes in the alteration produced in the sound of the instruments. The physical features that determine the effects caused by the mutes are the mass added to the system, the area of contact between them and the bridge (part of the instrument to which the mutes are attached), and the nature of their building material. The experiments compare the effect of (a) mutes of the same shape and material, but with different sizes and weights; (b) mutes of the same shape, size, and weight, but made of distinct materials; (c) isolated parts of a segmented mute; (d) the use of a combination of more than one unit of the same kind of mute in different configurations. The paper contains a brief description of violin mutes, the sampling methodology of the violin sound developed for the study, and the selected (psycho-)acoustic descriptors: loudness values, LTAS (Long Term Average Spectrum), and percentage of non-harmonic residual, obtained through SMS (Spectral Modeling Synthesis) from samples collected under different study conditions. Previous results have demonstrated the differences in intensity and timbre caused by diverse mutes. The present methodological investigation contributes to the understanding of the influences of distinct physical attributes of different types of mutes on the overall sound quality of the instrument.