Squillo


Squillo is the resonant, trumpet-like sound in the voices of opera singers. It is also commonly called "singer's formant", "ring", "ping", "core", and other terms. Squillo enables an essentially lyric tone to be heard over thick orchestrations, e.g. in late Verdi, Puccini and Strauss operas. Achieving a proper amount of squillo in any performing context is imperative: too much and the tone veers towards the shrill; too little and the purpose of the squillo cannot be achieved.
Squillo is easily recognizable by a distinctive brilliant, ringing quality in the timbre of the voice. This perception is caused by the presence of a peak in the 2 - 5 kHz frequency range, to which the human ear is particularly sensitive. 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. having naturally strong higher formants, are especially prized in opera because they allow a singer to maintain certain lyric qualities e.g. limpid high notes, and consistency of tone throughout the range etc. even in dramatic singing. Voices with squillo are also easier to record.
Uses of the squillo includes:
Famous singers who personify this technique include Leontyne Price, Mariella Devia, Renata Tebaldi, Giuseppe di Stefano, Jussi Björling and Luciano Pavarotti. Certain dramatic singers may also employ squillo as opposed to volume over the course of a performance, for example Birgit Nilsson.