vibrato, amplitude modulation, electroglottography, acoustic


Objectives: The goal of this investigation was to test a new methodology for measuring amplitude modulation (AM) at the level of the vocal folds during vibrato in trained singers, because previous research has suggested that AM arises in large part as an acoustic epiphenomenon through an interaction of the harmonics in the laryngeal source with the resonances of the vocal tract as the fundamental frequency oscillates.
Study Design: A within-subjects model was used to compare vocal activity across three pitch and three loudness conditions.
Methods: Seventeen female singers with a range of training and experience were recorded with a microphone and an electroglottograph. Fluctuations in the ratio of closing to opening peaks in the first derivative of the electroglottograph signal were employed as an index of laryngeal level AM.
Results: Evidence of laryngeal AM was found to a greater or lesser extent in all the singers, and its extent was not related to the degree of training. Across singers and pitch conditions, it was more prominent at lower intensities.
Conclusions: The differentiated electroglottograph signal lends itself to the measurement of AM at the level of the larynx, and the extent of the modulation appears more related to the level of vocal effort than to individual singer characteristics.

Original Publication Citation

Dromey, C., Reese, L., & Hopkin, J.A. (2009). Laryngeal level amplitude modulation in vibrato. Journal of Voice, 23, 156-163.

Document Type

Peer-Reviewed Article

Publication Date


Permanent URL






David O. McKay School of Education


Communication Disorders