Arabella, Royal Opera House, London Die Zauberflöte, Glyndebourne Festival Opera, Sussex Pelléas et Mélisande, Glyndebourne Festival Opera, Sussex

Oh no, I've lost my Filofax!

Poor Arabella! Deprecated as a pale imitation of Der Rosenkavalier, incredible of plot, absurdly opulent of score, and now set in a very nasty decade (the 1980s), in a very nasty lobby of a very nasty hotel where neither escalator works, where the stairs are legion, narrow and steep, and the staff are too busy moon-walking, body-popping and dancing on the ceiling to bring their guests a drink. Whatever next?

Poor Arabella! Deprecated as a pale imitation of Der Rosenkavalier, incredible of plot, absurdly opulent of score, and now set in a very nasty decade (the 1980s), in a very nasty lobby of a very nasty hotel where neither escalator works, where the stairs are legion, narrow and steep, and the staff are too busy moon-walking, body-popping and dancing on the ceiling to bring their guests a drink. Whatever next?

Tempting as it is to recommend shutting one's eyes for the duration of Peter Mussbach's yuppified Covent Garden-Théâtre du Chatelet co-production, to ignore all that happens on stage in Arabella would be a shame. Not only is the singing every bit as luminescent, generous and direct as you might expect from Karita Mattila (Arabella), Barbara Bonney (Zdenko/Zdenka) and Thomas Hampson (Mandryka), their facial acting is subtle and clever enough to suspend even close-range disbelief at the spectacle of three fortysomething people playing three twentysomething people in the kind of shoulder-padded couture and back-combed wigs that only three sixtysomething swingers might wear.

Clearly crinolines no longer cut the mustard. But I wonder whether too much is lost by randomly updating operas that depend on period-specific social mores? Mussbach's bizarre tribute to MTV's first decade indicates an obsessive awareness of Arabella's weak points and little appreciation of its strengths. But Strauss and Hofmannsthal were not fools and narrative slowness aside, Arabella is never less than focused - a point not lost on conductor Christoph von Dohnányi. Regardless of the distracting dancers, the criminally unflattering costumes and Erich Wonder's noisily aerobic set, Dohnányi has captured the chaotic vitality of this score quite perfectly. Sweet optimism crashes into despair, brittle wit into broad humour, tender eroticism into gentle teasing. The Royal Opera House orchestra respond with the fluency of an ensemble at the very top of their game. And the cast have tuned in to this heart-on-sleeve urgency with total commitment.

Not a moment is less than delightful. Not a moment is dull. Indeed, were I to make any criticism at all, it would be that Mattila rarely projects vulnerability; which, when you consider that her character is about to be forced into marriage to honour her father's gambling debts, is surprising. Vocally, it is a triumph for her, but dramatically it lacks that sheer, skinless innocence she brought to the title role of Jenufa. Still, Bonney's Zdenko/Zdenka is heartbreaking - deliciously unfolded and developed through the course of the opera - and Hampson's Mandryka is as sympathetic as he is swaggering. Of the supporting cast, veterans Artur Korn and Cornelia Kallisch provide expert comedy as the Count and Countess, Diana Damrau glitters gaily through The Fiakermilli's vocal gymnastics, Raymond Very (Matteo) suffers heroically, and Quentin Hayes, John Daszak and Iain Paterson excel as the rejected suitors, despite their Flock of Seagulls coiffure. Unmissable, even with your eyes open.

More rugs and pop now, though this time of the champagne picnic variety. Alas, I am unable to make any direct comparison between the two most recent Glyndebourne productions of Die Zauberflöte, having missed Peter Sellars' much-derided earlier interpretation. But set against David McVicar's 2003 Covent Garden production and Nicholas Hytner's 1989 ENO version, Adrian Noble's new Flute is tame and plain to the point of posing no questions about this work's odd blend of pantomime and pathos, much less resolving them. The Masonic issues are dodged, the dialogue is indistinct, Sarastro's priests are arranged around the auditorium like chattering choristers, the boys arrive on balloons in nehru jackets like miniature versions of Norman Parkinson, and the drip-dyed multi-coloured gauze backdrops look like scarves from the Glyndebourne gift shop.

It's all quite pretty in a middle-aged Home Counties Boho way but strangely subdued, which is surprising after Noble's exciting and affecting Ulisse for Les Arts Florissants, and frankly disappointing after Theodora, Iphigénie or Fidelio - to pick but three recent Glyndebourne successes. Jonathan Lemalu's plummy, patrician Papageno appears to have been modelled on Peter Ustinov, Peter Rose's Sarastro is stretched, and the Three Ladies unintelligible. On the plus side, Vladimir Jurowski's cultivated, spicy intensity combines well with the sweet, grainy sound of the Orchestra of the Age of Enlightenment, the animals - including a lovely porcupine - are charming, Lisa Milne's Pamina is pure and bell-like, Pavol Breslik's Tamino clear, intelligent and bright-toned: their "Tamino mein! Pamina mein!" moment the most delicious in an otherwise so-so show.

As if to illustrate what can be achieved at Glyndebourne, when conservatism and comfort are exchanged for imagination and intellectual rigour, Annilese Miskimmon's revival of Graham Vick's 1999 production of Pelléas et Mélisande opened 48 hours later. Conducted with dark, brooding energy by Louis Langrée, played with astonishing transparency by the London Philharmonic Orchestra, and sung and acted with exquisite character and colour by Marie Arnet (Mélisande), Russell Braun (Pelléas) and John Tomlinson (Golaud), this was another world indeed: a Freudian fantasy of otherness and assimilation acted out with ritualistic precision over designer Paul Brown's disturbing copper-toned floor of glass-enclosed funeral flowers. The most stunning and apposite set and lighting I've seen. The most enigmatic, absorbing score.

Which leaves space only to apologise to James Holmes, conductor of Opera North's The Seven Deadly Sins. Scintillating it certainly was, but in this case it was Holmes who scintillated and not, as stated last week, Martin André. Sorry.

a.picard@independent.co.uk

'Arabella': Royal Opera House (020 7304 4000), to 12 June; 'Die Zauberflöte'/'Pelléas et Mélisande', Glyndebourne (01273 813813), to 16 July