Simón Bolívar Symphony Orchestra of Venezuela, Dudamel, RFH

Youth may have vanished from the title, and its first flush is gone from the cheeks of most of the young persons. Now they’re in their prime, a magnificent sight – and the sound, too, is that of a world-class orchestra with a voice. Which we heard at its most distinctive, deep and muscular, from the strings in the opening signals of Beethoven’s Fifth Symphony. So what went wrong with the music from Wagner’s Ring in their first 2015 Southbank concert’s second half?

Ultimately the blame must rest with Gustavo Dudamel – when good, great, but horrid when he gets the wrong end of the stick, as I’ve heard him do in Mahler, and Wagner was a worse casualty last night. It didn’t help to be faced with an even emptier, brassy pageant so soon after the finale of the Beethoven (the louder and bigger the worse it gets, in my opinion). Wotan only knows whose “version” this was of the "Entry of the Gods into Valhalla" at the end of the first Ring opera, Das Rheingold. We got the warning Rhinemaidens minus the three voices floundering twice over at an agonizingly slow, unvocal speed, and missed the key event (Wotan’s big idea) before what Wagner intended as the deliberately empty pomp of the curtain. Hero Siegfried then loped off in search of new adventures and promptly died, was reborn under the tall forest trees and finally unborn as his aunts the Valkyries hoiotohoed in mid-air, not yet cognizant of his conception.

There are two ways to avoid the topsy-turviness: hire a soprano so that you can end where Wagner does, with Brünnhilde’s Immolation Scene, or turn to Henk de Vlieger’s hour-plus "orchestral adventure", an odyssey not that much longer than what we got which actually has time and scope to transport you somewhere (it certainly did that against the odds when Mark Wigglesworth conducted it at the Barbican). Transports might still have been possible here if Dudamel had made the orchestra soar rather than merely billow. As it was these edifices were built not on the flowing Rhine but over a swamp, into which they sank for whole swathes.

Had Dudamel (pictured right conductng last night) told the young players the stories? You couldn’t really picture anything until the lovely woodwind birdsong of Siegfried’s Forest Murmurs – dreamy beauty here from first flautist Katherine Rivas, oboist Frank Giraldo and clarinettist David Medina – and the irrepressible swagger of the Ride of the Valkyries. Isolde’s Liebestod as encore was better, flaming with the true Venezuelan intensity towards consummation, but how odd to feel nothing – my reaction, anyway – during Siegfried’s Funeral March at a time when it might have meant something for our collective grief after the events in Paris.

Maybe the disappointment struck all the more after so much was right about the Beethoven., at least on these massive terms (there's more than one other way of doing it which I prefer). One day some conductor and orchestra will make me value what the second movement’s trying to say, but at least this Andante was con moto (the more movement the better, surely). We didn’t need Dudamel’s involved grunt in the space before one of the opening rhythms dug deep to realise they start in mid-air, not on the first beat of the bar. The oboe solo that holds them up on their emphatic return is always a surprise, but no principal I’ve heard has ever phrased it with more feeling than Giraldo.

Showstopping moment of the evening? The double basses – six here, 12 for the Wagner – plunging with perfect articulation but plenty of that Simón Bolívar ferocity into the fugal lead of the scherzo’s trio. Horns, too, were as full-thrust as in any top orchestra when they needed to be. There are always thrills with this flagship team blazing a path for the future of music, but not quite enough of them throughout the evening on this occasion. Better luck with Orbón's Tres versiones sinfónicas and Mahler’s Fifth Symphony tonight.