BBC Symphony Chorus and Orchestra

Royal Festival Hall

Saturday evening saw the Estonian composer Arvo Part strolling through the Royal Festival Hall foyer, signing the occasional autograph and generally marking time before the , under Jukka- Pekka Saraste, tackled two of his most disparate works. Litany came first, flown in among high strings for a sequence of 24 short prayers attributed to St John Chrysostom. A grumbling bass drum marked deliverance "from eternal torments" and the Hilliard Ensemble tackled the brunt of Part's ecstatically chiming harmonies, with additional colour from the orchestra. Words provided the substance, and music a testimony of faith, love and acceptance. And yet it had not always been so. After the interval, Saraste offered us a sampling of Part in crisis, crossing the divide from "barbed- wire" modernism to a rarefied mode of tonality. "Credo is very different to Litany," one of the players told me during the interval - "and I think you'll recognise its opening idea!" He wasn't wrong: initial impressions of a transmogrified Bach-Gounod Ave Maria raised a visible smile or two. But rather than don satin robes, as Gounod had done for "his" Bach, Part uses the same Prelude - the first piece in Bach's "Well-tempered Clavier" - as the starting point for a violent musical breakdown, lulling us into false security before stripping his source of its harmonic stability and forcing what's left into a ferocious crescendo. It's ingenious stuff, built on sound theoretical principles, and the BBC Chorus sung or shouted as if possessed.

Credo's premiere caused a scandal, but Part was already preparing himself for pastures new. And he wasn't the only one to cut the cacophony and cast his eyes towards the heavens. Over in Denmark, his near-contemporary Per NOgard had already discovered what he calls the infinity series", a potentially endless chain of notes generated from the one musical interval. Like Part, NOgard uses minimal thematic material to maximum effect, in his case by making a single phrase run at different tempos simultaneously. The process could, in principle, have had us hooked for hours, but NOgard's Second Symphony clocks up a mere 23 minutes. It opens among quietly pulsing woodwinds, muted horns and strings before the brass "heavies" descend, make their mark and leave though not without shifting Nogard's time travellers onto a subtly altered course. In a fascinating pre-concert talk with Stephen Johnson, the rugged but amiable composer spoke in terms of the "silent counting" of one's unconscious, of the contrasts in tempo between heart- beat and breathing. His Second Symphony is, in a sense, the music of mathematics; and yet its drawing power made me want to abandon the Hall, find a CD of the piece and stan listening all over again. But had I done that, I would have missed Part and a memorable performance of Sibelius's Third Symphony where the finale's hypnotic repetitions served to remind us that in music, as in life, there's nothing new under the sun.

Rob Cowan