Full synopsis of "Rigoletto" could be found here.
Listen and watch the famous Quartet from the Rigoletto:
One of the finest examples of ensemble writing in all of opera occurs in Act III of. The stage is set so that the two characters inside the inn (the Duke and Maddalena) are unaware of the two characters outside (Gilda and Rigoletto). The audience gets a side view, with a clear visual differentiation of the double scene. Maddalena, the sister of the assassin Sparafucile (who has been hired by Rigoletto to murder his nemesis the Duke) has enticed the Duke to the inn. Outside, Rigoletto has brought Gilda to see what a horrible two-timing cheater he is. They peer into the tavern from the outside. After an introductory section consisting mostly of musical dialogue over a catchy orchestral melody (Ex. #11), the quartet proper begins.
The opening segment belongs entirely to the Duke--"Bella figlia dell'amore" ("Beautiful daughter of love") (Ex. #12a). It is a soaring, legato phrase that expresses his new found love for Maddalena.
Maddalena responds coquettishly in a staccato phrase that takes no more than a measure to express (Ex. #12b).
Gilda's voice, from outside the inn, responds immediately, starting on a high note and descending rapidly, with 2 short breaks in her phrase (Ex. 12c). She is beginning to realize that she is being betrayed.
Maddalena and Gilda repeat their phrases and the 4th member of the quartet, Rigoletto, then adds his voice to the ensemble saying in effect, "I told you so" (Ex. 12d).
The 4 voices now merge, but maintain their individuality throughout. Notice in the next example (Ex. 13) how the Duke and Maddalena alternate their lines of flirtation, while Gilda and Rigoletto, the uppermost and lowermost voices sing parallel rhythms in contrary motion.
Later in the quartet, Gilda has breathless, 2-note phrases; Maddalena laughs on 1 pitch; the Duke is still soaring with a legato phrase and Rigoletto holds up the bass of the harmony with 16th notes alternating with a long sustained C (Ex. #14). The four voice parts, individual not only in melody and rhythm, but also in the type of emotion expressed, add up to a quartet which is remakable in its psychological differentiation among the characters and yet at the same time, a unity of great power and persuasiveness.
Verdi - Rigoletto / Luciano Pavarotti, Ingvar Wixell, Edita Gruberova, Victoria Vergara, Ferruccio Furlanetto, Riccardo Chailly