The BBC Symphony Orchestra’s Barbican programme with the stylish American conductor James Conlon was odd. It made an interesting link between La Mer, Debussy’s symphonic sketches, and Edgard Varèse’s massively orchestral Amériques. But two Britten pieces, one admittedly maritime (Four Sea Interludes from Peter Grimes), the other with a French connection (the tenor-and-string-orchestral Rimbaud settings, Les Illuminations), were in a different world, aesthetically speaking. They were enjoyable enough, but as a preamble to La Mer, the interludes, for all their evocative brilliance, were distinctly clunky.

What music wouldn’t be by comparison with Debussy’s preternatural sophistication? This strong account — Conlon conducting from memory and bringing his tempo and textural elucidations to bear with fine immediacy — left me marvelling at the work’s scale of originality. Barely of the 20th century (it was completed in 1905), these three movements not only revolutionised the concept of the symphony, but created an unprecedented kind of continuity that would utterly transform music. No matter how often one listens to La Mer, one receives it, I believe, not as a succession of themes and developments, but as a series of discrete moments, each intensely present yet somehow holding together with absolute inevit- ability. Where did such a magical discourse come from? Perhaps Wagner’s juggling of motifs in his operas pointed the way, but it is a far cry from Parsifal to the new universe of Debussy’s Prélude à l’Après-midi d’un faune (1894), if merely a dozen years later.

This new mode of connecting ideas by sheer internal magnetism made possible such defining statements as Stravinsky’s The Rite of Spring and a work evidently indebted both to it and La Mer, Amériques. Varèse’s prodigious score — it was brought off magnificently — expresses his euphoric immigrant’s response to New York City and is permeated by the sound of the siren and the vehicular din simulated by the string drum known as the lion’s roar.

The volume of articulate noise generated by the piece — it needs no fewer than 15 percussionists, as well as quintuple woodwind and sextuple trumpets; this in the composer’s reduced version of 1927 — defies belief, though Varèse’s subtlety is shown by the fact that he gets the (wooden) whip to play quietly. But his bravura use of Debussy-like fragmented continuity is hardly less arresting. As a ritual procession of blocks of sound, a sort of verse-and-refrain structure (the refrain provided by the alto flute heard at the start) and an example of casual, almost naive gigantism, Amériques could be a work by Birtwistle, and Varèse has influenced numerous composers besides.

One of them is the Austrian Olga Neuwirth (b1968), a figure whose rise to international prominence is linked to her 2000 piece Clinamen/Nodus, written for the London Symphony Orchestra and Pierre Boulez, and including in its unusual, rowdy scoring a pair of sirens and a lion’s roar. At LSO St Luke’s, in the first of three presentations there by the London Sinfonietta, Neuwirth’s piano concertante locus ... doublure ... solus (2001) had its British premiere under Martyn Brabbins, with Nicolas Hodges as soloist. The title reveals an inspiration in the experimental writer Raymond Roussel’s novel Locus solus, and the interpolated word indicates that the pianist has a double, a distorting reflection, in the form of a sampler-player. The soloist sometimes “prepares” his piano à la Cage by inserting objects between the strings, and distortion, as a positive, indeed high-energy, principle, animates the piece. Stylistically it can embrace the bleatings of an ad hoc mouth-organ quartet and a burst of Messiaen birdsong. As an exploration of cacophony, it ran Amériques close.

If its cheerfully mobile, segmented form (the central sections can be played in any order) also harks back to Varèse, and behind him Debussy, the work does not take discontinuity to the parodic limit marked by Tippett’s Piano Sonata No 2. This was the opening item of an excellent piano recital given by Andrew Zolinsky under Park Lane Group auspices at Wigmore Hall. He did not persuade me that the rather galumphing, over-terse, studiously repetitive movement comes off, but nobody else has. He did, though, give us a marvellously alive Haydn sonata (Hob:XV1:24, in D), realise the ferocious virtuoso wit of Unsuk Chin’s Six Etudes and wrestle mightily with the Liszt Sonata.