The melodies of Monteverdi's concertato works contain many formulaic maneuvers, ornamentations, and melodic gestures so imaginatively simple as to be almost like musical blank space. But the success of his solo vocal lines is not based on their inventiveness, or even, strictly speaking, their expressive strengths. It's based on his deftly poised balance of quivery, rhythmic, and ornamental passages against passages of long, sustained notes. These contrasts of kinesis and stasis in the line follow upon each other in eloquent succession, unfolding an absorbing musical narrative. In plainer terms, it's a question of melodic phrasing that Monteverdi, even though solo vocal writing was essentially new to him, handles with a natural ease. His grasp of the idiom is so solid that it feels like listeners are hearing the result of a long-established tradition, not a style at its very inception. Amor, se giusto is a splendid example, containing many passages worthy of the more advanced Book 7.
The opening delivers reams of melody in the delectable new style. Soprano, bass, and tenor are concerted in succession, solo over continuo. The final tenor passage is an interesting syncopated succession of intervals, plain as a glass of water, barely "melodic" at all, but perfectly crafted to form a structural conclusion to the opening passages. Compared to the rather depressed mood of the more traditional madrigals in Book 5, this is quite merry, although, like almost everything in Book 5, the emotional quality is fairly muted and subtle. If anything is truly sunny here it's the multi-voiced passages, the first of which appears in an almost florescent contrast after the end of the tenor's solo. There's no dialogue within the poem, so these choruses aren't narrative commentary, they are intensifications of the already strong narrative through-line initially carried by the solo voices. Instead of the cantata-like setup, Amor, se giusto is structured as a triptych. After the first chorus passage, the madrigal, in its third phase, becomes more polyphonic in orientation, the shiny melodic lines like cloisonné over the plain, ever-reliable sound of keyboard continuo. ~ Donato Mancini, Rovi