Open and covered singing as studied by means of fiberoptics, inverse filtering, and spectral analysis

Covering the voice near the passaggio is a technique mainly used in male classic Western singing. The purpose is said to be to smooth the register transition and avoid register breaks. The physiological and acoustical differences between open and covered singing near the so-called passaggio were investigated by means of fiberoptics, inverse filtering, and spectral analysis. The study corroborated previous findings that covering physiologically means a widening and lengthening of the pharynx. Acoustically, covering implies a change of formant frequencies, and an elevated sound pressure level of the lowest source spectrum partial, i.e., the fundamental, resulting from an increased transglottal air flow. The findings indicate that covered singing also is associated with larynx lowering. Covered singing near the passaggio shows similarities to so-called phonation, and is probably preferable from the point of view of vocal hygiene.