How Does Anyone Sing That High? A Different Part of the Voice Entirely

Ordinary singing vibrates the whole length of the vocal folds, with pitch controlled by their tension and mass. In this mode the folds are pressed together along most of their length and only a very short section near the front is left free to vibrate, producing a much higher frequency from a much smaller vibrating element, in the same way that shortening a string raises its pitch. The sound produced is thin, pure and has few overtones, which is why it resembles a whistle, and the mechanism uses a small volume of air at relatively low pressure compared with loud singing in the ordinary range.

The characteristics are distinctive and the applications are specific:

• •Frequencies above roughly the C two octaves over middle C
• •A pure tone with very little harmonic content
• •Little dynamic range, since it cannot easily be sung loudly
• •Limited ability to shape vowels, so words are hard to hear
• •Used in coloratura soprano repertoire for specific effects
• •Used extensively in popular singing since the 1980s

Confirming what the folds are doing required seeing them during production, which is difficult while somebody is singing. High-speed filming through a laryngoscope, capturing thousands of frames a second, has shown the pressed closure and the short vibrating segment directly, and confirmed that the mechanism differs from ordinary high singing rather than being an extension of it. Imaging has also shown that the vibrating section can be extremely short and that the folds may not fully separate on each cycle, which explains the pure tone. Not every singer producing very high notes uses the same mechanism, and the boundary between this and a very high ordinary register is not sharp.

Placing this mechanism among the others makes the distinction clearer. The lowest is a rattling creak produced when the folds are very slack and vibrate irregularly, used in speech in some languages and in some singing styles. The main speaking and singing range uses the full depth of the folds vibrating together. Above that a lighter mechanism engages in which only the edges vibrate, which is what most singers use for their upper range. The mechanism described here sits above that again. The transitions between them are where voices break, and training aims to make those transitions smooth rather than to eliminate them.

Teachers disagree about the safety of training it, and the disagreement is substantive rather than merely conservative. The case against is that forcing the mechanism, particularly by pressing hard or singing loudly in it, strains tissue that is under considerable tension, and that singers who develop it without guidance frequently acquire tension habits that damage their ordinary range. The case for is that the mechanism itself uses low air pressure and is not inherently strenuous, and that many singers use it routinely for decades without harm. The consensus position is that it is safe when approached gently and at low volume and unsafe when pushed, which is true of most singing.

Pressing the vocal folds together along most of their length leaves a short section free to vibrate, which produces a very high pure tone from a small vibrating element using little air. High-speed filming through a laryngoscope confirmed the mechanism is distinct rather than an extension of ordinary high singing. Words are hard to form and volume is limited, and safety depends on not forcing it.