Music: Hair by Figaro. Outfits by C&A. Vulgarity by the Royal Opera

I don't mind the fact that the Royal Opera, which once dressed its productions in Versace and Armani, now shops at C&A: clothes matter less than how they're worn. But the problem with the RO's new Barbiere di Siviglia at the Shaftesbury Theatre is that it wears its High Street couture like a back-street tart - in a production of such shabby, crass third-rateness that it's hard to believe the company's management ever allowed it near a stage. And if that sounds like the thumbs-down I gave a few weeks ago to the RO's not- so-Merry Widow, I can only tell it like it is.

In fairness, this Barbiere marks the first attempt of the designer Nigel Lowery to turn director in a mainstream theatre, and I understand what he has tried to do. Casting around for some contemporary correspondence to Rossini's brilliant, brittle lunacy, he has settled on the slapstick of non-primetime children's television, complete with comic-strip policemen, twirling-ladder jokes and cameo appearances from Sooty and Sweep.

But slapstick routines aren't just a matter of shoving a man on stage with a custard pie: they need some skill, a sense of timing. This is just a clumsy mess of vacuous, misfiring gags imposed on a genre of theatre that would resist them even if they worked. Barbiere may be brittle, but it isn't brutal. Lowery's apparent inability to discern more than a vowel- sound's difference between those two words is the undoing of his show.

Result: it moves at a funereally leaden pace (not helped by the workaday conducting of one Antonello Allemandi). The exuberance of Rossini's finest comic numbers falls flat. And it takes more than the collective talents of a youngish, good, but not particularly starry cast to keep things afloat. Romanian mezzo Carmen Oprisanu makes an attractive British debut as Rosina, and provides the chief vocal interest; but Roberto Frontali's bullish Figaro and Paul Austin Kelly's disappointingly pinched Count aren't enough to save the night.

The boos began at the interval. By the end they were jeers. And, like others in the audience who had spent the past weeks fighting Covent Garden's corner against government attack, I sat wondering why I'd bothered. Defending the Royal Opera these days is like defending Khartoum against the Mahdi.

Defending Prokofiev as a composer of substance as well as popular appeal might be a better bet, and he certainly needs it. Shostakovich has passed into history as the martyred genius of Soviet music; but Prokofiev is passed off as a dazzlingly shallow entertainer who toed the Party line. The extent to which he too produced music of depth that challenged the system - like the 6th Symphony, or the "war" sonatas - tends to be forgotten.

His centenary celebrations in 1991 began the shift to a more balanced view, and the London Philharmonic's new Prokofiev Series at the South Bank will no doubt take things further. But the series opened on Tuesday with a piece that shows Prokofiev at his most popular and politi- cally obliging: the 1938 score for Eisenstein's cinema epic Alexander Nevsky, which the LPO played in live accompaniment to the film itself.

Nevsky was a landmark of patriotic propaganda masquerading as history: black-and-white in every sense, designed to contrast the sturdy heroism of Russian sons of soil with the dastardly evil of everyone else - not least the Germans, with whom Stalin had yet to sign his infamous pact. It was an opportune vehicle for the rehabilitation of Prokofiev and Eisenstein, both of whom had left Russia after the Revolution and returned to find themselves branded western sympathisers. It also proved one of the most remarkable collaborations ever known between the media of sound and celluloid, and rare in that it gave the composer an uncommonly free hand. For some scenes the score was written before the filming, so images come tailored to sound rather than sound to images. And there aren't many composers who get that sort of deal today, beyond Michael Nyman.

The score accordingly has an independence which Prokofiev was able to refashion into a concert cantata without much trouble. And although it contains certain literalisms - ringing bells and jostling crowds - there's an odd capriciousness in the determination of what does and doesn't merit musical response. The first five minutes of the battle on the ice - a set-piece whose advancing horses would instantly get the full works from any putative John Williams - runs to nothing but the sound of clattering coconuts. And it's at such moments that Alexander Nevsky's two lives, as film and music, divide. In cinematic terms it's ancient history. As a score it holds its ground within the modern world. And whatever Prokofiev's debt to the stage pageantry of Glinka and Mussorgsky, the sheer impact of his score will always bear that out: even in a performance like this one, under Carl Davies, where the punches didn't hit, or land, quite squarely.

The Huddersfield Festival of Contemporary Music, now in its 20th year and a world-recognised platform for all things new, had something of its own to say about image-sound relationships in a touring mime-with-music called Beyond the Blue Horizon. A comic vision of the end of the world, it was staged with mind-blowing invention by Trestle Theatre Co (who do the best pantomime camel this side of the Sahara), and played to a 90-minute score by David Horne: the young Scots composer I first encountered years ago at Huddersfield when he was about 13 and premiering one of his own piano pieces with such fierce attack that he broke a string.

His Horizon score is more pacific, fixed to a considered course that at most seems to mirror the stage action in miniature, its gestures restrained. But there's an intense musicality in the writing, beautifully realised in performance by the Britten Sinfonia under the oboist-conductor Nicholas Daniel. And it all presents in meaningful terms, which is more than you can say for Huddersfield's supposed big draw this year: an "operatorio" by the French composer Pascal Dusapin, that proved a grand, but puzzling and ultimately damp squib.

Called Romeo et Juliette, it had less to do with Shakespeare than with the general practices of theatre that lend themselves to parody - having fun with the way music-theatre enlarges emotion to excess while it reduces narrative to telegram essentials. Beyond this, and an eclectic battery of styles and stances from late Romantic to African Ethnic, I couldn't tell you what Romeo et Juliette set out to achieve; and frankly, I'm none too interested. A French period-piece from the 1980s, it's a product of its time and place, and probably best left there.

Meanwhile, in the world beyond Huddersfield, last Saturday was the feast of St Cecilia: patron saint of music and dedicatee of a civilised little festival at Stationer's Hall, London. Reviving the custom of this same hall some 300 years ago, when a "Society of Gentleman Lovers of Musick" met here and commissioned works like Purcell's Hail! Bright Cecilia for their pleasure, the St Ceciliatide Festival is run by a conductor-academic, Penelope Rapson, and features her own period ensemble, Fiori Musicali. I heard them last week in a concert chiefly memorable in that it used a "basset" clarinet: the dodo-defunct instrument for which Mozart's Clarinet Concerto was first written. A reproduction, it looked like the sort of plumbing you find under a sink. But the extra depth of sound does make a difference and, played with fluency by Colin Lawson, it convinced me that this dodo could well fly again, given some handy spanners and a monkey- wrench.

'Barbiere': Shaftesbury, W1 (0171 304 4000), Mon-Fri.