A well-trained sense of hearing, familiar with every possible variety of vocal tones, was the old masters’ main reliance in the training of the voice. What the ear told was never questioned, and the insight it gave into the workings of the voice was sufficient for all the purposes of vocal training along instinctive lines. A deep sympathy with the voice, a love of its beauties and an understanding of its needs, are to be discerned in every page of Tosi and Mancini. The old masters had a horror of everything which strains or overtaxes the voice. Their instincts taught them what to do and what to avoid. Throughout all their teaching they acted on the principle that the faculty by which the voice is judged is lodged solely in the ear.
Much more of time and attention is needed to acquire the old masters’ understanding of the voice than to cover the entire ground of vocal science. While an exhaustive study of the subject would call for two years of application, a smattering of anatomy and acoustics may be obtained in a few months, sufficient at any rate for a grasp of the accepted scientific principles of tone production. But to know the voice as the old masters knew it, several years of almost daily experience in listening to voices are required.
Taylor, David Clark. “New Light on the Old Italian Method: An Outline of the Historical System of Voice Culture, with a Plea for Its Revival.” (1916).