According to a study by Matthias Echternach from the University of Freiburg, Christian Herbst from the University of Vienna and colleagues, vocal changes in professional singers may stem from vibration patters in the Vocal Chords, which are only noticeable by singing experts. The singing process known as Passagio, which is a technique used by professional singers, is a technique in which western classical singers are trained in order to minimize perceptible variations in the quality of The voice when transitioning to different vocal registers. Although the passagio in female singers is not totally known, experts analyzed it for the first time.


This is a technical term referring to the transition area between voice registers. The passagio, in musical terms, lies at the boundaries of distinct voice registers in a singer, thus there is a passagio in each of the different vocal registers; chest voice, middle voice and head voice. One objective in classical music is to maintain a smooth timbre when approaching a passagio in a given vocal register. The human voice is divided into three distinct types of registers; the chest voice, the middle or mixed voice and the head voice. Every man and woman possess them and they`re named after the area of the body in which they occur.

The study on the passagio of women

The researchers of this study analyzed the first and second passagio in 10 professional soprano singers.

They recorded the vibrating vocal chords of the singers endoscopically and found the distinct vocal vibratory patterns. The more drastic differences were noted when the singers were transitioning from the first to the second passaggi. Varied transitions between the registers were found when the voice chords were held open for either short or long duration during the partial loss of contact between the vocal chords.

It was found that variations in vocal chord vibration made the passaggio more audible.

Voice registers analysed

This study concluded that audible registers are able to be heard even in the most trained professional singer, revealing that the larynx may undergo some type of process to minimize the audible sound. The varied singing strategies are thought to be induced by the anatomy of their voice or varied singing techniques.

Both the visual and the audible recordings helped researchers study vocal chord vibrations and their effect on the passaggi. It`s hoped that future studies in this area may help get a deep understanding on the singing styles in other music genre, including pop, rock and musical singing.