A Statistical Metric for Stability in Instrumental Vibrato

摘要

When instrumentalists perform with vibrato, they add a quasi-periodic frequency modulation to the note. Although this modulation is rarely purely sinusoidal, many methods for vibrato parameterization focus exclusively on the rate and depth of the frequency modulation, with less attention given to measuring how a performer's vibrato changes over the course of a note. In this paper, we interpret the vibrato trajectories as instantiations of a random process which can be characterized by an associated autocorrelation function and power spectral density. From these distributions, a coherence time can be estimated that describes the stability of the vibrato within a note. This metric can be used to characterize individual performers as well as for resynthesizing vibratos of different styles.