The prime example is John Eliot Gardiner and his Monteverdi Choir, who celebrated their 30th anniversary this week with two concerts at London's Guildhall. It was a questionable choice of venue, partly because the Guildhall was so security- conscious that it didn't allow Gardiner to advertise where the concerts were taking place (you had to ring a mystery phone number to find out), and partly because the acoustic there reduces solid vocal textures to an indistinct roar.
But the programme (repeated twice) was a fine showcase for the choir, whose virtuosity has few equals anywhere in the world. Of course, there was some Monteverdi - acknowledging how things began 30 years ago, when Gardiner was still a Cambridge undergraduate and coerced some friends into a performance of the then relatively unknown Monteverdi Vespers. There was also Purcell and Schutz. But the main work, a piece de resistance in every sense, was Poulenc's mighty outpouring of anguish at the wartime occupation of France, Figure Humaine. This was followed by a new John Tavener commission, The World is Burning, and a selection of Percy Grainger's endearingly vulgar folk-song arrangements that conscripted Gardiner's period-instrument players into unaccustomed roles. The sight of refined spirits like baroque lutenist Jakob Lindberg vamping through O Danny Boy and Shallow Brown was cherishably surreal.
But then, Gardiner has redefined himself as an all-rounder. He is about to take his choir off to Vienna to record, of all things, The Merry Widow, and he has the Midas touch to bring it off. The virtue of the Monteverdi Choir is that, although an Oxbridge product, it has made a lifelong stand against Oxbridge manners. The sound is fuller, the blend more challenging than you would find in a chapel choir, thanks largely to the mix of genders; and the whole approach is riskier, sanctioned by secure techniques in every section and a number of voices of genuine solo calibre.
The impression Gardiner Enterprises Inc (Monteverdi Choir, English Baroque Soloists, Orchestra Revolutionnaire . . .) gives of a slick business operation isn't born out by the obvious commitment and exploratory exuberance of individual performances. That Gardiner likes grands projets is nothing to complain about when they include such things as the Berlioz Messe Solemnelle, which was among the concert highlights of last year and is now out on an equally outstanding Philips disc. His 30th-anniversary package is to be recorded, too. Though it's not so long since he was similarly packaging the 25th, I don't think anyone could begrudge him another pat on the back.
The Solomon Trio has only been going since 1990 and, sad to relate, is about to disband. The constitutions of trios never seem to be as solid as those of quartets - with one or two prominent exceptions, they tend to be made up of players of individual distinction whose relationship is fluid. Yonty Solomon, Tim Hugh and Rodney Friend are all very distinctive individuals (not least in the temperament of their playing) with separate careers. So perhaps their collective life always had a sell-by date. But they have produced some wonderful recordings, and there was a poignancy about their penultimate appearance together last weekend at Lavenham in Suffolk. This focused on the core piano trio repertory - Beethoven's 'Ghost' and 'Archduke', Haydn's 'Gypsy', Dvorak's 'Dumky' - where nicknames drop like rain and tunes rise with a bold, assertive strength. But rarely with such forceful strength of character as here in the Solomons' opening programme - the sort of unfussed music-making where everything made sense and spoke with a direct, clear voice.
I also liked the London Sinfonietta's contribution to the Spanish Arts Festival: a tough programme of not especially rewarding new Spanish works, elevated by Roberto Gerhard's Harpsichord and Piano Concertos. They both required massed strings, which are not the Sinfonietta's forte. But both observed the tension in Gerhard's writing between pounding inner energies and restraining outer structures that squeeze them into a toccata- like continuum. And the Piano Concerto, with an entrancing Puccini-meets-Schoenberg middle movement and a jokey finale, covered a wide emotional territory with conviction.
The Eugene Onegin that opened at ENO on Thursday was supposed to have been a restaging of Graham Vick's 1989 production. But as Vick is doing an Onegin for Glyndebourne in June, the whole thing was handed over to a former ENO staff producer, Julia Hollander. She was left to do something different - with new designs but not much extra money.
It could have been an interesting challenge. The sets just about survive their cheapness, thanks to deep, dark lighting; and the shadows help you ignore the cotton-wool beards and nightmare wigs. But there's no ignoring the fact that Hollander fails to draw a single compelling performance from her cast - except, maybe, for Bonaventura Bottone, who's clear, resounding Lensky triumphs over the worst wig of them all. Peter Coleman- Wright's Onegin is firm, strong and promises more than it delivers. Cathryn Pope's Tatyana is harsh, sullen and unlovely.
There is, however, one reason to hear this Onegin and it's Alexander Polianichko: a Russian conductor from the Kirov who inspires the orchestra to beautifully shaped string phrasing, buoyant rhythms and a lighter caress than his Kirov boss Valery Gergiev gave Onegin last year at Covent Garden. Not that Gergiev wasn't a sensation; but Polianichko has his own distinctive qualities. I hope we'll be hearing more of them.
'Onegin' continues Thurs & Sat, Coliseum, 071-836 3161.