Arthur Paté

Predicting the decay time of solid body electric guitar tones

Although it can be transformed by various electronic devices, the sound of the solid body electric guitar originates from, and is strongly linked with, the string vibration. The coupling of the string with the guitar alters its vibration and can lead to decay time inhomogeneities. This paper implements and justifies a framework for the study of decay times of electric guitar tones. Two damping mechanisms are theoretically and experimentally identified: the string intrinsic damping and the damping due to mechanical coupling with the neck of the guitar. The electromagnetic pickup is shown to not provide any additional damping to the string. The pickup is also shown to be far more sensitive to the out-of-plane polarization of the string. Finally, an accurate prediction of the decay time of electric guitar tones is made possible, whose only requirements are the knowledge of the isolated string dampings and the out-of-plane conductance at the neck of the guitar. This prediction can be of great help for instrument makers and manufacturers.

Influence of the Electric Guitar's Fingerboard Wood on Guitarists' Perception

The sound of a solid body electric guitar comes from the loudspeaker transducing into sound the string velocity. Because of mechanical string-structure coupling, the string vibration, and therefore the sound, substantially depends on the lutherie parameters. This study focuses on the comparison between ebony-fingerboard and rosewood-fingerboard guitars: is a change in the fingerboard wood perceived by the guitar players? In order to test the hypothesis that it is actually perceived, a psychological investigation is carried out. Two experimental methods are used: a free sorting task with recorded stimuli from the guitars (listening test) and a free verbalisation task where the guitarists play the guitars. In the listening test, the guitarists perceive differences between guitars, but the resulting clusters do not show an ebony/rosewood dichotomy. A linguistic analysis of the verbalisations exhibits psychological descriptors that are relevant for the discrimination of the wood of the fingerboard: PRECISION (referring to how each note stands out from others), and to a lesser extent ATTACK (referring to the guitars response to musicians gesture) and BALANCE (referring to the frequency content). This study is part of a broader project aiming at establishing an explicite relation between mechanics, perception, and lutherie. A physical interpretation of the psychologically-relevant descriptors is eventually proposed in order to use them as hypotheses in a further hypothetico-deductive approach starting from physics and using psychophysical methods.

On the Perception of Audified Seismograms

ABSTRACT Recordings of the Earth’s oscillations made by seismometers, following earthquakes or other geophysical phenomena, can be made audible by simply accelerating and playing them through an audio reproduction system. We evaluate quantitatively the possibility of using such an acoustic display of seismic data for practical applications. We first present to listeners examples of two categories of data, based on geophysical parameters that are not revealed to them. In the first test, the control parameter is the terrain, either oceanic or continental, sampled by the propagating seismic wave. In the second test, it is the geometry of the seismic fault, which can be either thrust or strike slip. The listeners are asked to associate each of a set of audified seismograms, that are presented to them binaurally, to either one of the two categories. At the end of the test, they are asked to define the features of audified signals that helped them in completing their task. The third and final test consists of repeating the fault‐geometry categorization exercise after a brief training session. About 35, 27, and 17 listeners participate in the first, second, and third tests, respectively. Both sexes, a wide range of ages, and three different backgrounds (acousticians, geoscientists, and physicists) are represented. Although the number of listeners is too small for a definitive statistical analysis, our results suggest that listeners are able, at least in some cases, to categorize signals according to all the geophysical parameters we had chosen. Importantly, we clearly observe that listeners’ performance can be improved by training. Our work opens the way to a number of potentially fruitful applications of auditory display to seismology.

On the perception of audified seismic data

Auditory display of scientific data has been applied successfully to several disciplines. Seismic recordings can be “audified” by accelerating them before playing them through an audio reproduction system. We present a suite of experiments, designed to help determining whether auditory display of seismic data can find practical research applications. Experiments consist of asking listeners to (i) categorize audified seismograms that are presented to them binaurally, and (ii) define with a few lines of text (that we later analyzed semantically) the features of audified signals that helped them in completing this task. In a first experiment listeners categorize freely, i.e., they form their own categories: they are found to follow similar categorization strategies, which suggests the existence of auditory clues perceived by most of them. From these results it is, however, hard to identify a simple correlation between such clues and the geophysical parameters that should control the data. In a second round o...

Influence of plectrum shape and jack velocity on the sound of the harpsichord: An experimental study

A controversial discussion in the musical community regards the ability of the harpsichord to produce sound level or timbre changes. The jack velocity (controlled in real time within a musical context) and the plectrum shape (modified by the musician or maker prior to the performance) appear to be the two control parameters at the disposal of the harpsichord makers and players for shaping the sound. This article initiates the acoustical study of the control parameters of the harpsichord, presenting a framework for the investigation of these two parameters with means of experimental mechanics measurement. A robotic finger is used for producing repeatable plucks with various jack velocities and plectrum shapes. The plectrum bending, vibrating strings initial conditions, and radiated sound are recorded and analysed. First, results are obtained from measurements carried out on one string, for four plectrum shapes and four jack velocities. The plectrum shape has been found to have an influence on its bending behavior when interacting with the string; on the strings initial conditions (position and velocity); and on the resulting sound (sound level, spectral centroid, and decay time). The jack velocity does not have an influence on any of the measured quantities.