Alto

In music, an alto or contralto is a singer with a vocal range somewhere between a tenor and a mezzo-soprano. The term is used to refer to the lowest female singing voice, or to a kind of countertenor (who can also be mezzos or sopranos. Alto pieces normally span between F# below middle C to the E a tenth above middle C (i.e. F#3-E5). At the bottom of their range, altos sound almost like tenors. Some altos have even larger ranges; from the C below middle C to the C two octaves above (C3-C6 if middle C is C4), but like all singers, their vocal type is defined mostly by their "vocal center" and not by their range (a soprano for instance could technically possess the lower range of an alto, but would not be comfotable singing it). In four part choral harmony, the alto is the second highest voice. Alto pieces were originally written in the alto clef, but now use the treble clef.

Although both men and women may have voices in the alto range, the word is usually used to mean a female singer. The word "contralto" can be used to refer specifically to a female alto singer, versus alto male singers or instruments or clefs. However, choirs singing early music frequently include adult male altos, also called countertenors. In English church usage, the term alto is sometimes exclusively used to mean a boy with this range, while contralto is used for a female singer. However, this is not done consistently, and for most practical purposes, alto and contralto can be thought of as synonyms (the phrase "boy alto" can be used if there is a chance of misunderstanding). A few popular music enthusiasts define the contralto and alto separately, as the contralto having an especially dark range, from the D above low C to Tenor C, which is essentially a female of tenor range, while alto is a voice with a range from F below middle C to the F an eleventh above middle C, and is closer to the mezzo-soprano. The majority however define contralto and alto as synonyms, and assign the adjectives light and dark, with a dark alto being a female of tenor range, while a light alto, commonly referred to as simply alto, to include mezzo-sopranos as well.

In medieval polyphony, the principal voice was the tenor. When additional voices were added, they were called contratenor (meaning "against the tenor"). When two such voices were added, they were called contratenor alto and contratenor bassus, indicating high and low respectively.

Contraltos are fairly rare in opera, since there is very little work that was written specifically for them. Most of the time, contralto roles are limited to maids, mothers and grandmothers, but they do occasionally get notable roles, with witches being the most common outside of the three former roles (A common saying among contraltos is that they're only allowed to play "witches, bitches, or britches"). Baroque opera features a large number of alto roles.

The word, "alto", is often applied to instruments to indicate their range in relation to other instruments of the same group. In common usage, particularly among jazz musicians, the word has become synonymous with the alto saxophone. In US usage the alto horn is an Eb saxhorn, a brass instrument.