Vocal-tract resonances and tuning strategies in singing

Résumé En

For most singers, being able to sing more loudly, or to sing with less effort and strain, or a combination of both is a desirable goal. One way of achieving increased acoustic efficiency is to tune the resonances of the vocal tract to the fundamental frequency of the note sung and/ or to one of its higher harmonics. To what extent do they do that? This presentation reviews recent studies by the authors on resonance tuning in singing. We use a technique that measures the acoustic impedance spectrum of the tract (roughly speaking its frequency response) during singing. The most widespread tuning strategy is to match the first vocal tract resonance to the fundamental of the note sung, a technique practiced by many sopranos, whether trained or not, and also by lower voices on closed vowels towards the top of their ranges. Tuning of the first resonance to the second harmonic is practised by altos in belting and in Bulgarian singing. Much less consistently, male singers sometimes tune that resonance to the second or higher harmonics. In the extremely high range, above sopranos' high C, the range of the first resonance is exceeded. Of the singers we have studied who sing well above this pitch, all have tuned the second resonance of the tract close to the fundamental sung.