A Rossini comedy is supposed to be a veritable orgy of whipped-cream fun for the ears, with vocal flourishes and trills piling atop each other, crowned with sustained high Cs and E-flats like glistening cherries. In evaluating the Metropolitan Opera’s new production of “Le Comte Ory” (Count Ory), a rarely-done piece that had its first-ever performance at the Met on Thursday night, it’s hard to know whether to praise the company for providing a very nice hot-fudge sundae, or to lament the fact that it didn’t offer an all-out banana split. When you’re talking about fun, how much excess is too much?

There’s a slight mutedness built into “Le Comte Ory” -- though “muted” is an unusual word to describe an opera about a thoroughly naughty count who begins the action disguised as a hermit so that all the pretty girls will bring him gifts and tell him their secrets, and spends the second act disguised as a nun so that he can get into the castle, and more, of the attractive Countess Adele. It’s muted because a lot of the score was adapted from “Il viaggo a Reims,” a frothy and brilliant piece Rossini wrote for the coronation of King Charles X in 1825, which was, being tailored to a specific occasion, not performed again until the opera was reconstructed and returned to the stage in 1984. Never one to let good music go to waste, Rossini recycled quite a bit of it in “Ory,” but it lost some of “Viaggio’s” sense of pure ridiculous fun in the process.

Not that “Ory” lacks for good music. The Act II trio is one of the highlights of Rossini’s output (“Ory” was his last comedy, and his penultimate opera; only “Guillaume Tell” lay between him and several decades of voluntary retirement). And hearing it sung by Joyce DiDonato, Diana Damrau, and Juan Diego Florez, three of the best vocal technicians on the opera stage today, is about as good as it gets — particularly, some might add, when the three of them are engaged in heavy petting in a big double bed.

So why did I leave “Ory” feeling a bit disappointed? It wasn’t the fault of DiDonato, who as the page Isolier gave her usual consummate performance, voice shining and true, character every inch the very young man he is supposed to be.

Nothing else, though, was as fully satisfying as she was. As Adele, Damrau sang beautifully; I hadn’t heard her for a few years, and was delighted to hear that the sheer radiant gorgeousness of her sound was still there. I wished, though, that she would sing out more. She phrased with skill and sensitivity, taking phrases from quiet to semi-loud and back to express the nuances of her character’s sometimes outraged modesty. I wanted a little less nuance. Italian opera wasn’t written to be delievered with good taste; Adele’s first aria, in particular, is a chance for a soprano to come out on stage and take the audience by the throat, and I wished Damrau had taken more opportunity to show off rather than constantly fussing with the details.

As for Florez’s Ory: his first aria left me bewildered. In the concert he gave through the Washington National Opera a month ago, he sang with ringing strength. His sound always has a slightly nasal cast, but nothing like the odd, squeezed, forced tones he achieved here. After his character threw off the hermit’s disguise, things improved vastly on the vocal front. I was left to surmise that the first impression was partly a result of his attempt to assume a character, which didn’t quite work. (The coloring of French vowels makes many singers sound more nasal in any case.)

The whole beginning of the opera was not quite the thrill I had anticipated: Florez was muted; the soprano Susanne Resmark, making her debut as the lady in waiting Ragonde, sounded shaky; Michele Pertusi, as Ory’s tutor, was unimpressive; and the conductor, Maurizio Benini, merely adequate, and not always that. There were some significant coordination problems, and the big ensemble at the end of Act I, a tour de force for unaccompanied voices, often sounded out of tune.

Resmark, to her credit, improved; she turned out to have a big voice with a contralto’s rich boom and a soprano’s range, which sounded great once she began singing with more confidence. And Florez redeemed himself, clearly enjoying playing a rake, finding his usual voice, and delivering some falsettos that had a nectary sweetness largely absent in his normal singing. The baritone Stephane Degout was another bright spot as one of Ory’s sidekicks. The other aspects, including the lackluster conducting, didn’t get much better.

Bartlett Sher offered a perfectly fine, colorful production, casting the whole thing as a play-within-a-play on a period stage, with stooped stagehands in 18th-century garb (Catherine Zuber) manning the sound effects and the winches that raised and lowered elements of the scenery (by Michael Yeargan) from the flies. Sher’s Met productions so far -- this is his third, after “Barber of Seville” and “Tales of Hoffmann” -- have not been entirely to my taste; here, too, I thought there was room for more insight and focus, beyond the slightly generic entertainment of bustling choruses and gesticulating singers. Why, in that climatic Act II trio, was the key plot twist of having Ory grope Isolier when he thinks he is caressing Adele reduced to a writhing, adolescent heap of bodies? Couldn’t there be a better way to bring off the opera’s ending, which sounds as if Rossini simply got bored and decided to wrap things up as fast as possible? But Sher’s productions have pleased so many people I am willing to recuse myself from the debate and simply be happy that others appear to enjoy them.

Le Comte Ory runs through April 21; it will be broadcast live in HD in movie theaters around the country on April 9.

Other views:

Anthony Tommasini in the New York Times.

Mike Silverman for the AP.

David Finkle on TheaterMania.com.

Corinna da Fonseca-Wollheim on The Classical Review.

And the Met’s Peter Gelb gets space to write his own advertorial for the company in The New York Times.