What is meant by a cultivated voice? When may a voice be said to be cultivated? What are the distinguishing characteristics of the trained singer?

The nature of the answers to these questions will depend somewhat upon the point of view, for different individuals will have different standards. But regardless of schools and methods, there are certain things which all musicians expect to hear in the trained voice. For example:

An even scale from top to bottom of the voice. No weak tones, no depressions. A pure legato and sostenuto.

A clear, telling resonance in every tone.

A sympathetic quality.

Ample power.

Perfect ease and freedom in production throughout.

A perfect swell, that is, the ability to go from pianissimo to full voice and return, on any tone in the compass, without a break, and without sacrificing the tone quality.

The ability to pronounce distinctly and with ease to the top of the compass.

Sufficient flexibility to meet all technical demands.

An ear sensitive to the finest shades of intonation.

An artistic concept or musical taste of the highest possible order.

This is a brief outline of the work which is expected to be done as a preparation for artistic singing. The standard is high but not impossible.

How this work is to be done, the modus operandi, the method, if you please, is a secondary matter. It is purely personal, and something each teacher will decide for himself. People going to the same point often go by different routes. The destination, not the route, is the chief concern.

Clippinger, David Alva. Systematic voice training. Gamble Hinged Music, 1910.