Among all the confused terms employed in singing to denote the compass, register and character of the human voice, there are four which may be said to represent elemental types: soprano, alto or contralto, tenor and bass. These names are used to denote the composition of the chorus with sub-divisions of firsts and seconds, to determine how the parts must be divided. (Sopr. I, Sopr. II etc.) While the range of an instrument is exactly governed by its construction, the compass of the voice, on the other hand, depends on the individuality of the singer. It is therefore impossible to define the exact limits of each of these vocal types. When it is a question of dividing choristers into 1st and 2nd parts, those with the higher voices are classed among the firsts and vice versa.

Besides the principal terms mentioned above, the names mezzo-soprano (between sop. and alto), and baritone (between tenor and bass) are also employed.

Apart from these denominations which represent the six principal solo voices, a quantity of others are in use to denote either compass, timbre or technique, such as light soprano, soprano giusto, lyric soprano, dramatic soprano, light tenor, tenorino-altino, baryton-martin, lyric tenor, dramatic tenor, basso cantante ("singing bass"), basso profondo (deep bass) etc. To this lengthy list must be added the term mezzo-carattere, of intermediate character (between lyric and dramatic soprano, for example).

If we try to discover the real meaning of these designations it soon becomes apparent that they are derived from widely different sources—for instance, "light soprano" implies agility and mobility in the voice; "dramatic tenor", the power to express strong dramatic feeling; basso profondo signifies great resonance in the deep register.

Minute examination of all the methods of attack and emission of sound lies within the province of the singing master and to enumerate them here would only perplex the student. The same applies to the position and exact limits of register (chest voice, middle and head voice in women; chest voice, mixed voice and falsetto in men). The work of a teacher of singing consists in equalising the voice throughout its whole compass, so that the transition from one register to another, on all the vowels, may be accomplished imperceptibly. Some voices are naturally even and flexible. The professor of singing must correct faults in breathing, determine the range of the voice and place it, equalise its tone, increase its flexibility, instruct as to the pronunciation of vowels, modulation from one grade of expression to another, etc. A composer should be able to rely upon flexible and equal voices without having to trouble himself as to the abilities or defects of individual singers. In these days a part is seldom written for a particular artist, and composers and librettists do not find it necessary to entrust a certain rÔle to fioriture singers, another to heavy dramatic voices. Poetic and artistic considerations demand greater variety of resource in the study of opera or vocal music in general.