It’s the music that’s always been most stirring about The Light in the Piazza—not the story, about a stifled American reawakening to life as she anxiously watches her sheltered daughter discover love under the Tuscan sun, but the ravishing melodies that frame the tale and give those conflicted feelings wings. So the word that Arena Stage would produce a stripped-down “chamber version” of the musical, with five players standing in for a band whose string section alone had more members than that on Broadway, was intriguing: Would a more intimate staging make up for a smaller sound? Maybe the freshness of a smaller ensemble would turn up something new? Molly Smith’s staging does offer one discovery: Nicholas Rodriguez, who brings an appealing impetuousness, a blessedly unforced tenor, and a sure instinct for a musical phrase to the part of Fabrizio, a 20-year-old Florentine who falls hard for the pretty, childlike Clara Johnson as the musical opens. Elsewhere, the production’s pleasures are more alloyed: Margaret Anne Florence wields a pretty soprano that hardens metallically just where Guettel’s melodies ask it to bloom, and Smith has seemingly encouraged her to telegraph Clara’s developmental disability (related to a childhood accident) from the outset, rather than allowing the audience to discover it by stages. Similarly broad strokes define lesser characters—Fabrizio’s brother (Jonathan Raviv) seems more of a buffoon than I recall, and his mother (Mary Gutzi) more of a manipulator—and the entire ensemble is hemmed in by a set that turns the leisurely tradition of the passeggiata into a cramped circular stroll. Small gratifications, then: The ache as Hollis Resnik parses the bitter marital memories of Margaret Johnson’s “Dividing Day,” and the simmer as she and Ken Krugman (as Fabrizio’s urbane father) sort out their differences in the jazzy, minor-key “Let’s Walk.” If there’s nothing newly illuminating in this Piazza, it does at least put Guettel’s score in front of a new audience, who with any luck will discover a Clara-sized passion for it.