You may be wondering why a mezzo is singing this famous “coloratura soprano” role. Rossini actually wrote the part of Rosina as a mezzo. Most current productions transpose the role and cast a soprano. Robert Lawrence, in his notes for the Schirmer edition, points out that
Rossini was probably the first among opera composers to limit the excesses of his singers (who loved to improvise and embroider in performance) by writing out the precise embellishments which he expected. Despite this care taken while he lived, the story of “The Barber of Seville” in modern performance is one of galloping mayhem onthe part of prima donnas and producers.In this Parlophone recording, the duet is severely cut and the tenor part almost entirely disappears so that the piece has more the character of an aria. The few remaining tenor lines are sung by Manurita.
The role of Rosina was originally written for a mezzo-soprano . . . and in this pristine version the heroine’s dark vocal coloring brings a delightful contrast to the reedy light tenor of Almaviva, the baritone brilliance of Figaro. Somewhere in the emerging nineteenth century, the part was “adapted” for coloratura soprano, with changes of key, modifications of notes, and a loss of musical profile. The bewitching “Una voce poco fa”, when given to a high soprano voice, transposed a half-tone upward, tricked out with all sorts of added runs and trills, is so effectively disguised that one has a hard time recognizing Rossini’s original tune. The charming duet of the Lesson Scene, “Contro un cor che accende amore” [heard here], is usually scrapped by high sopranos because of its low tessitura and some giddy display piece inserted at the singer’s disgression.