New man Previn and a very sexy Così

LSO/André Previn | Barbican, London Così fan tutte | Glyndebourne Festival Opera

It's some consolation that as you slip into your 30s, age gaps cease to matter. Of course, it helps if you break off all contact with friends who are still twentysomething, but longevity seemingly smooths out all differences except the relative merits of Double Deckers and White Horses. Certainly I'd forgotten there was any gap between myself and my concert-going friend when we set off for the Barbican last week until she started to wax lyrical about André Previn's Music Night, the TV moment that hooked her into classical music at an impressionable age. Clearly I missed that by a couple of seasons for, like many less high-minded children, my André Previn TV moment was Eric Morecambe's massacre of Grieg's A Minor Piano Concerto under the cool baton of "Andrew Preview" on the Morecambe and Wise Show.

It's some consolation that as you slip into your 30s, age gaps cease to matter. Of course, it helps if you break off all contact with friends who are still twentysomething, but longevity seemingly smooths out all differences except the relative merits of Double Deckers and White Horses. Certainly I'd forgotten there was any gap between myself and my concert-going friend when we set off for the Barbican last week until she started to wax lyrical about André Previn's Music Night, the TV moment that hooked her into classical music at an impressionable age. Clearly I missed that by a couple of seasons for, like many less high-minded children, my André Previn TV moment was Eric Morecambe's massacre of Grieg's A Minor Piano Concerto under the cool baton of "Andrew Preview" on the Morecambe and Wise Show.

I've been a lazy concert-goer over the years as far as Mr Previn goes, but I've bought his recordings - less for Previn's interpretations of other composers than for his own compositions. Setting aside the unfortunate "jazz" with Dame Kiri, Previn's collaborations (with Yo-Yo Ma, Barbara Bonney and a host of the major talents of the last two decades) have been excellent. His 1992 orchestral song-cycle Honey and Rue (a setting of sharp and clever texts by Toni Morrison written for the famously demanding soprano Kathleen Battle) stays close to my CD player, and, for all the critical carping about "pastiche", Previn is undoubtedly a fine songwriter. So, as far as I was concerned, the lure last Sunday was not Previn's celebrated interpretation of Vaughan Williams, nor was it the chance to hear Renée Fleming sing the Four Last Songs, but the UK premiÿre of the arias from his latest opera, A Streetcar Named Desire.

Alas, there was no Renée Fleming, so apologies to those who turned up - as I did - expecting the reigning Miss Strauss. And this meant that there was no Streetcar, for Fleming was Previn's Blanche and the arias are hers. Fleming's absence left a terrific opportunity for the British soprano Janice Watson to step in for the Strauss, but left the Previnites with the disappointing Diversions - a 16-minute-long orchestral suite commissioned by the Mozarteum and premiÿred by the Vienna Philharmonic last year.

The concert kicked off with Mozart's 39th Symphony - at best a subtle beginning but in this case quite dull. With the massed forces of the LSO in front of him (an orchestra whose potential Previn knows well through years of directorship of one form or another) he chose moderate tempi, moderate phrasing and moderate dynamics, ranging from mezzopiano to mezzoforte but mostly just mezzo. It was like being in a very expensive, very fast car on an open (unpatrolled) road and cruising at 55 mph - comfortable but frustrating. How much of this was down to age I couldn't say - Sir Colin Davis is still full of beans at 73 - but having last seen Previn in the Seventies it was a bit of a shock to see him in his seventies. What moments of interest there were in the symphony were generated by the leader, Gordan Nikolitch, who was visibly attempting to pull some detail out of the smooth musical monolith. Minute by minute it was very lovely but it didn't seem to have much to do with Mozart.

Previn looked no more lively in front of his own composition. Without the distraction of intelligent lyrics, Diversions was so heavily in pastiche mode that it devolved into a musical puzzle - like one of those boxes of letters where the object is to find as many words as possible, horizontally, vertically, diagonally. In this four-part work we managed to spot 13 composers: the usual American suspects (Gershwin, Barber, Copland) plus a handful of European greats - melodically, harmonically, texturally. I don't mind pastiche, but I draw the line at sincerely flattering both Strauss and Disney in the same breath - I'm sure I heard "bibbity bobbity boo" at one point - and I was starting to feel pretty miffed with Renée Fleming for landing us in this mess.

Things picked up after the interval; Vaughan Williams's Fantasia on a Theme by Thomas Tallis was richly persuasive, the chamber ensemble at the back of the orchestra sounding at times like a viol consort. Previn looked, and conducted, like a new man, and the textures were sharply defined with clear and daring colouration. I still dislike the piece itself (having fallen in love with Tallis's original unadorned melody, the Fantasia for me feels like flock wallpaper on Le Corbusier) but Previn did more to persuade me of Vaughan Williams's respect for Tallis than any other performance I've heard. It seems strange that such a cosmopolitan conductor should have found his musical home in the English pastoral, but this repertoire is clearly still where Previn's strength lies.

The Strauss was no less sumptuous, but laboured under tempi that did little to assist Janice Watson or, for that matter, the audience. The tempi were a hangover from the fashion for slow Strauss that started in the Seventies with Jessye Norman's inexorable recording of the Four Last Songs. All very well in the studio but difficult to pull off live, and a million miles from the fresh and flowing performances of Lisa Della Casa in Strauss's lifetime. Watson's incisive, brightly attractive tone and intelligent phrasing was stretched to the limit by Previn's speeds; the close of "September" was so drawn out that there was really nowhere left to go with "Beim Schlafengehen" and "Im Abendrot". The sheer sound was heavenly - as it always is in Strauss and as it always is with the LSO - but the measured ecstasy of these songs was pulled too far to breathe, and the poetry was forced into word-by-word delivery. On the basis of this museum-piece performance, I'm curious to see what Previn will do with the Brahms Requiem tonight; a piece that really depends on its poetry - curious and anxious.

The revival of Così fan tutte at Glyndebourne a few days earlier could not have been a greater contrast, with lively tempi, swift action and fresh performances from orchestra and singers. Having had misgivings about Graham Vick's stilted Figaro I was surprised to enjoy the Così from which it was extrapolated. The rehearsal-room concept works well, there are some lovely set-pieces from the chorus, and an interesting Freudian subtext at play in the relationships between the four young lovers and the very parental Despina and Alfonso - Elizabeth Gale and Alan Opie, both consummate comedians. The cast looked and sounded very sexy (anyone who thinks opera singers are naturally overweight should see this production) especially Laura Polverelli and Nathan Gunn as Dorabella and Guglielmo, neither of whom would be kicked out of bed for eating biscuits by any sane individual. The only question-mark was over Alexandra von der Weth's slapstick Fiordiligi (a bit of a tart from the start in Vick's production), whose sexual capitulation lacked any poignancy despite an enchanting performance of "Per Pieta". I'd advise waiting for the performances that Sir Andrew Davis is scheduled to conduct, as Davis seems to draw much more shape from the orchestra than does Louis Langrée, but this is an enjoyable, intelligent production.

'Così fan tutte': Glyndebourne Festival Opera (box office 01273 813813) to 14 Aug