Impact of acoustic resonances on overtone correlations across a large musical instrumental database

When performers use vibrato, the pitch and intensity of the note is modulated in order to create an expressive effect. Although one might expect that vibrato would produce a proportional frequency modulation in each of the overtones, this is not always the case. Past work has shown that the instantaneous frequencies of some instruments, particularly bowed strings, tend to exhibit reduced overtone correlation when performed with vibrato. Additionally, the presence of reverberation in a recording has been shown to reduce the correlation between overtones for many instruments. In this study, we present an analysis of overtone correlations for a wide range of instrument sounds taken from multiple large databases. Using this large library of tones, we illustrate the effect of instrument resonators on these correlations for tones performed both with and without vibrato.