BBC SO/Slatkin, Barbican Hall, London

An experiment in disintergration

It was a good night for the pentatonic scale. Five notes full of Eastern promise. And some fulfilment. The piccolo and side drum of the BBC Symphony Orchestra began with an oriental trinket by Weber, a theme more key than incidental to his music for Schiller's five-act drama Turandot and as good a way as any of setting up Puccini's Turandot later in the evening, to say nothing of that cracking scherzo from Paul Hindemith's tirelessly inventive Symphonic Metamorphosis of Themes by Carl Maria von Weber.

This is exactly the kind of piece in which Leonard Slatkin excels. His sense of rhythm, his ear for inner voicings, really paid off here. That, and the movies in his mind. You can always tell the man had a Hollywood childhood. The Turandot scherzo was a bit of a comedy thriller, woodwind and horns sending trills like shock waves through the orchestra; Turandot's hapless suitors, perhaps, quaking in their boots. The audacious jazzy variant at its heart – a fugue with attitude – "kicked ass", as Slatkin's countrymen might say. East met West, West took what it wanted and left.

A bit like Colin McPhee in Tabuh-tabuhan. The Canadian-born composer journeyed via Bali to Los Angeles. You can hear it in the music. West Coast gamelan. This protracted, three-movement "toccata for orchestra and two pianos" – remarkable more for its influence (it dates from 1936) than its content – could (and probably did) keep Philip Glass in arpeggios for life. It does for Bali what John Adams did for China.

But for Madam Mao read Princess Turandot. The last act of Puccini's famously unfinished opera was the real reason we turned out in decent numbers at the Barbican. Franco Alfano's completion, as truncated and unforgivably mangled by Toscanini back in 1926, is the ending we generally hear. A rousing unison reprise of "Nessun dorma" and we all go home far happier than we should. Not very satisfactory. Luciano Berio has now "re-imagined" that ending and the result is more an experiment, a musicological exercise, than a serious attempt to finish the job.

As Slatkin conspicuously discarded his full score at the point where Puccini officially ended and Berio now began we entered another world, the harmonic language suddenly transformed. Curdled, hallucinatory, forward-looking, in the manner of Richard Strauss's Elektra or even Berg's Wozzeck, remnants of Puccini drifted through Berio's orchestral miasma. The voices, along with the libretto, became secondary. They no longer "belonged". Nothing belonged.

Moments of sweet consonance sat uneasily (and intentionally, I'm sure) in the midst of this harmonic disintegration. The music darkened ominously but unrecognisably. At least the final moments were suitably ambivalent, the sound literally decaying to remind us of the terrible price paid for the icy princess of death to find love. It was clearly going to take more than a kiss – a blow-torch, perhaps – to melt Eva Urbanova's strident Turandot.

Dennis O'Neill gamely set about the task with a decently stylish "Nessun dorma", but it fell to Amanda Roocroft's tragic Lui to warm hearts, the thrill of the voice in altissima achieved through the feeling that carries it there. Berio could learn from that.