Besides the principal terms mentioned above, the names mezzo-soprano (between sop. and alto), and baritone (between tenor and bass) are also employed.
_Note._ In the chorus mezzo-sopranos are classed with 2nd sopranos or 1st altos, baritones with 2nd tenors or first basses, according to quality and timbre of voice.
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.