Blogger’s note: Mancini’s pedagogical remedies have been underlined below.
A voice that is robust, crude and strident has no other need than to become sweetened and purified. If one says to a youth who has such a voice… ‘Give all the voice,’ surely he will not be able to correct the error; indeed, it will be made greater, because one cannot thus correct the bad quality, but rather increase the irregular and crude flexibility. In this case then, one ought to return to the scholar that quality of voice which is proportionate to his strength and age; and with assiduous attention one should achieve the sweetening of the strident voice, by acquiring the high tones; finally the whole register will become perfect in its total equalization. These advantages cannot be gained except through the most assiduous diligence, regulated by a solfeggio made up of notes of length, which ought to encircle the low notes, pass to the middle of the voice, and finally mingle with and unite the high voice. The union of these voices should form a mixture so perfect as not to ruin the union of the entire register. One cannot hope to obtain all of this if he strays from the indicated rule, since only through the calmness and spinning out of the voice can one correct crudity and stridency. Once the scholar has arrived at the possession of a happy and secure execution through this method, he can extend those steps, which he will make guided by wisdom and by the accuracy of his discernment, acquired through experience.
The other quality of voice which we have noted as defective but correctable through study and art, is that of a limited register and somewhat weak. This type of voice is certainly at a disadvantage, because it is only apt for use with good effect in small places: a very notable disadvantage, since necessity constrains us to sing now in large places, now in small. One should not abandon absolutely such a voice, because we can be sure to be able to administer some help with study, enough to render it richer and stronger.
With a student of tender years one should never use violent remedies, but always the mildest and least dangerous. Of all these my faithful master, Experience, has made me feel one to be the best, which I here propose to you: Reflect: a voice that is limited and weak, whether it be Soprano or Contralto, will gain a not inconsiderable advantage, if in its daily study it is cultivated with a solfeggio composed of long notes; and the success will be even more secure, if this same solfeggio does not exceed the range which its own nature permits at this time. One must counsel the student to increase little by little the body of this type of voice, regulating it with the help of art, and continual exercise; finally you will arrive at making it robust and sonorous. This first obstacle overcome, one may change solfeggios, which ought now to be augmented by notes a little higher; and since this second portion of the voice belongs to the register of the head, as I have proved already, I shall speak in the following article of how to unite them: One cannot produce a good effect if the voice is not equalized and united in its whole range. (ed.:!!) With this continuous and well-regulated exercise, which should occur in the first years of every scholar, and with the aid of age, which carries with it the reinforcement of the chest, and wisdom for guiding the studies well, he will certainly obtain that quantity of voice which will be sufficient for him to make himself heard in every place, no matter how vast.
Mancini, Giambattista. Practical reflections on figured singing. Vol. 7. Pro Musica Press, 1967.