For male singers in the western operatic tradition the upper part of the frequency range contains a series of pitches called passaggio, the transition between ‘chest’ and ‘head’ registers. Although there is no generally accepted objective definition of the distinction between ‘head’ and ‘chest’, the distinction is widely recognized among singers and voice teachers, as is the term ‘cover’, a technique often considered to be helpful in a proper execution of passaggio. On the basis of spectrographic, electroglottographic, and sub- and supraglottal pressure measurements on professional singers’ ‘correct’ and ‘incorrect’ singing of passaggio, this study offers a definition of t