The amplification of these particular harmonics is believed to be a result of a narrowing of the Aryepiglottic fold just above the larynx. Voices with naturally acquired squillo, i.e.
The enhancement of these specific harmonics is thought to be due to a constriction of the Aryepiglottic fold above the larynx, resulting in voices with naturally acquired brightness, i.e. those possessing a certain quality or character.