© Lloyd W. Hanson 1998
[Head Voice and Falsetto]
I would add my opinion to the discussion of falsetto and head voice. It is based on some 40 years of teaching voice and the good fortune of studying with some excellent teachers. Much of the this material can be found in Richard Miller's "The Structure of Singing" and in Barbara Doscher's "The Functional Unity of the Singing Voice" and in Berton Coffin's "The Sounds of Bel Canto". I am also drawing on my own research survey of concepts about falsetto which was published in the NATS "Journal of Singing".
Any discussion of head voice and falsetto involves a basic consideration of vocal phonation. Resonance, of course, has an effect on phonation in these areas, as it does in all areas of singing, but the primary differences between falsetto and head voice are phonational. The modern definition of falsetto is a voice production in which the vocalis muscles (for simplicity's sake the thyro-arytenoids) are inactive and lengthened greatly by the action of the crico-thyroid muscles which are at their nearly maximum contraction. The sound is produced by the air blowing over the very thin edges of the thyro-arytenoids and the pitch is controlled mostly by a regulation of the breath flow. If, at any time, the thyro-arytenoids began to resist this extreme lengthening of themselves and provide some resistance to the action of the cryco-thyroids, the vocal mechanism begins to move into head voice.
The sound of the falsetto voice is weak in overtones and produces no singer's formant. This is because the very thin edges of the lengthened vocal folds, which do not display any tension in opposition to the stretching action of the thyro-arytenoids, are easily blown open by the breath and offers little resistance to the breath flow.
The sound of the head voice, however, is richer in overtones and has the potential to produce a substantial singer's formant. In other words, it has a "ring". This is caused by the increased tension of the thyro-arytenoids which creates a 'tighter" and more substantial edge to the vocal folds which, in turn, resists the flow of breath and builds a more noticeable pressure below the vocal folds (subglottal pressure). The male singer can easily sense this difference in breath pressure between the true head voice and the falsetto.
It is possible to move gracefully between the falsetto and the head voice. If the male singer can gradually increase the activity of the thyro-arytenoids in resistance to the stretching action of the crico-thyroids the tone will change from the flute-like quality of the falsetto to the ringing sound of the head voice and the singer will also experience the increase in subglottal pressure. It is a bit of vocal gymnastics that not all singers can achieve. It is also an ability that is not necessary. This change from falsetto to head voice (or, for that matter, from head voice to falsetto) is not the heart of the mezza-voce or sotto-voce sound. These latter techniques have much to do with a change in the resonance spaces for the singer. In other words, mezza-voce and sotto-voce are more involved with changes in resonance of the voice than they are with phonational changes of the voice.
The vowels have a strong effect on the transition from chest voice to head voice. The point at which the male singer enters into a "call" or "shouting" voice as he ascends the scale on the [a] vowel is usually considered to be the lowest or first point of his passaggio or bridge into head voice [primo passaggio]. The singer may be able to extend this "call" voice about another fourth upward at which point he will usually switch into falsetto (if he is an untrained singer) or head voice (if properly trained) and this is his topmost or second point of his passaggio or bridge into head voice [secondo passaggio]. The difference between these two register activity points is known as the "zona di passaggio". However, if the same exercise is attempted in the [i] vowel the male singer will move into "call" voice and change into head voice about a minor (or major) third lower. This is the effect of the vowel on the register change.
Closed vowels such as [i] and [u] tend to lower the register change points. It is believed this is caused by the difference in acoustic "load" these vowels provide for the vocal folds. In effect, this increased acoustic load allows the vocal folds to make their adjustment more easily because they are not required to be the sole engines of resistance to the increased breath pressure as the pitch rises. The acoustic load provides some of the resistance necessary.
This is one of the reasons that men generally prefer closed vowels in the passaggio and above. The other primary reason for this vowel preference is the availability of a rich harmonic environment in the male voice which is able to activate the first and second natural resonances of the vocal tract (formants). An excellent article on this effect in the male passaggio can be found in the latest issue of the Journal of Singing (the official publication of the National Association of Teachers of Singing).
How much a singer is using falsetto or how much he is using head voice is not difficult to determine in most cases. If there is any ring to the tone, it is likely that the thyro-arytenoids are somewhat active and the transition has been, or is being made to head voice. If the tone is flutey and disembodied it is likely falsetto. But it is all a matter of degree.
Lloyd W. Hanson, DMA
Professor of Voice, Pedagogy
School of Performing Arts
Northern Arizona University
Flagstaff, Arizona 86011