What's the Difference Between an Alto and a Mezzo-Soprano?

In choral singing, voice parts are normally listed as soprano, alto, tenor, and bass. A four-part, mixed voice choir is frequently referred to as an 'SATB choir,' where SATB is short for soprano-alto-tenor-bass. So if SATB is for a chorus of women and men, what do you think an all-women's chorus would be? Take a guess--and read on! It's an 'SA choir,' or an 'SSAA choir.' However, since all of these women's voices are notated on the treble cleff, a women's chorus is most often referred to as a Treble Choir.

You'll remember from my previous blog post that voice classification in individual singers is somewhat different than the names of voice parts in a chorus or ensemble. However, when we get to bigger concert pieces, like the Mahler Symphony No. 2, the score (sheet music) lists the soloist's voices like the choral voice parts.

Let's use the Mahler Symphony No. 2 as an example. It calls for an orchestra, an SATB choir, a soprano soloist and an alto soloist. A soprano soloist sings the soprano solo and a mezzo-soprano then sings the part of the alto. A true alto, a contralto, can also sing this part, but as you read last time, there aren't as many true contraltos as there are mezzos and their ranges are similar. That's why mezzo-sopranos so frequently sing alto.

Which is exactly what I do. I am a mezzo-soprano (my voice classification), however I sing the alto part in many oratorios and concert pieces. I sing the alto solo in Handel's Messiah, in the Pergolesi Stabat Mater, the Mozart Requiem and in Bach's Christmas Oratorio.

There are scores in which the composer calls for a mezzo-soprano soloist, in which case it's pretty clear:  a mezzo-soprano sings the mezzo-soprano solo.

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Do you have a question about voice parts, singing, or music? Email me and I'll answer it here on the blog!