Così fan tutte, Royal Opera/ Joyce DiDonato, Wigmore Hall

Two very different lessons on love this week. From the Aphrodite-like Joyce DiDonato at the Wigmore Hall, there emerged a correct, wise, honest way to achieve an enamoured state; from the familiarly fickle cast of Così fan tutte - an almost unwatchably faulty bunch of emotional primitives in Jonathan Miller's production for the Royal Opera - very much the wrong way.

Miller is absolutely right to press home the point about the unattractiveness of Così fan tutte's group of solipsists. A mirror is the star of the show as a result. No one can escape it. Fiordiligi (Sally Matthews) falls for its reflexive charms just when a tone of near-genuine emotion is being reached by Dorabella (Nino Surguladze) over her lover Ferrando (Charles Castronova). The boys fool around in it, playing war games, flexing muscles, on the eve of their pretend march to battle, all while the girls sing fretfully around them.

No one in Miller's Così has the maturity to deal with anyone's emotional wellbeing but their own. Their own satisfaction is paramount; stuff everyone else. It's a take on the opera that makes sense not only of the scenario but also of the music, which are full of mocking allusions to grand tragedies by Gluck, full of fakery and falseness. Conductor Julia Jones did a fantastic job of emphasising the necessary lightness of this self-obsessed way of being. The earth was rarely encountered in her springy string lines, mirroring the way these flighty souls rarely sought to engage the truth.

The games within games, the coldness of the contemporary setting - a minimalist affair, perhaps an interior designer's showroom (another facade), tasteful to the point of self-extinction - and the psychological self-absorption can spiral into meanspiritedness. But Miller provides a joyous number of observations on modern ways, on quotidian details of gesture and movement, on humour and props (including plot-propelling iPods), which leavens the cynicism.

As usual with Miller, even in revival, the acting was outstanding. Surguladze's Dorabella got better and better as her voice and body relaxed into the role and her pouty, bug-eyed, flirty, inner Betty Boop came out. Troy Cook's Guglielmo (who disguises himself as a metalhead) was as saucy as Castronova's Ferrando (who becomes a hippie) was soulful. Don Alfonso (William Shimell) was nicely flinty but a little absent.

Sally Matthews as Flordiligi displayed a level of acting intelligence that is very rare for the operatic stage, full of delightful subtleties. Her doubling over with laughter was a triumph, as was her false modesty, as was her awkwardness and despair. Her voice, however, too proficient and tightly upholstered, left me unmoved. Best in both fields was Helene Schneiderman's sympathetic old schemer, Despina, a tough role, in that it's meant to be funny but rarely is. Well, Schneiderman, who once played Dorabella in a past revival, pulled it off brilliantly, adopting a perfect amoral nonchalance to her ill-advised guidance.

The end of this Così - as of any decent Così - leaves a thoroughly unpleasant taste in the mouth. Indeed, Miller makes it even more acrid than usual, the characters scattering left and right, fearful and bemused. There's no love here. And there perhaps never was.

American mezzo Joyce DiDonato's medley recital of love songs charted a far more sage and heartfelt course through the whirlwinds of romance. There were no tales here of double-dealing or manipulation, just simple songs of love and loss, sweetness and regret.

The selection ranged from the Arie antiche, a trove of early songs that stretch back to the 16th century, to the works of obscure Italian late Romantics and Debussyan acolytes. None of this recherché digging was in vain. Almost every single piece on this programme was a masterpiece in some way. The Arie antiche were particularly haunting. 

DiDonato's voice is a big, generous sound. It will fill whatever musical pot it has to fill and spill over some. When it combines with the spare melodic and harmonic patterns of the 16th, 17th and 18th centuries -  which in the powerfully scorched stillness of the Caccini ("Amarilli mia bella") resembled the yellow flatlands of Puglia - it can't fail to mark you, almost in the way the late great Lorraine Hunt Lieberson could. There was wisdom in her sighed Parisotti ("Se tu m'ami") and a bittersweet honesty to the Luigi Rossi ("Mio ben, teco il tormento").

Next to this piercingly plain-speaking collection, the Beethoven Four Ariettas, Op 82, seemed too unnaturally artful, too clever in accompaniment and - except for the second version of "L'amante impaziente" - too lacking in charm for it to have an effect.

DiDonato was just getting going, however. An aria from Rossini's Otello was up next when a mobile went off. "It's Otello," she asides quick as a flash, "Tell him it's not true." What fun. We lilted our way through the Rossini, an encore and the interval, straight into the 20th century.

First came the pungently vivid images of the Italian Debussy, Francesco Santoliquido, a remarkable composer on the evidence of his I canti della sera (1908), then the dark skies of Ildebrando Pizzetti. Interestingly, DiDonato's voice seemed slightly more suited to this late Romantic repertoire. Having such a big, bountiful voice, she almost loses control of the classical works. In the Santoliquido, the vocal spillages were a delight, a rightful bursting forth of the soul.

In the last songs DiDonato had fully descended from on high. She had started the recital, in Greek dress, singing of love and its travails almost in the abstract, as an experience to be navigated in this way or that, as if a counselling Aphrodite. In the last four songs, she was roaming our paths as a real-life love-entangled Carmen. And just as we were getting used to the new sassy Joyce, she flicked on a bow-tie, knocked her knees together and launched into Cherubino's "Voi che sapete" with a few boyish gulps.

It would have brought the house down, if she hadn't then launched into a showstopper from Rossini's La donna del lago, which, for the first time, really showed off the possibilities of her tessitura - comfortable in both directions - her flexibility, her abilitiy to conjure up new textures from thin air and at speed. With this virtuosic display, a return of divinity, the house was quite ready to explode. And explode it did.

• Visit the Royal Opera House website for further information on performances of Così fan tutte. Check out the rest of the Royal Opera House season here.
• The Wigmore Hall season continues tonight with the piano duo Paul Lewis and Steven Osborne.
• Visit Joyce DiDonato's website for information on her forthcoming projects and engagements.