Prom 20: BBC SO / Robertson, Royal Albert Hall, London

Considering that an accurate performance of its intricate interactions seemed barely possible when Stockhausen completed it in 1957, Gruppen for three orchestras (1955-7) has done rather well here, periodically drawing rather large audiences.

The performances that bookended this Prom reminded us why. Whatever dubious theorisings went into its fabrication, the result achieves a genuine impetus, from the antiphonal delicacies of its earlier sections, via rampaging climaxes, to the almost tonal resolution of its fadeout.

With the BBC Symphony Orchestra split into three ensembles, two of them in among the promenaders, maybe only those at the front barrier experienced the full antiphonal effect. But it was fascinating to take in these readings under the batons of David Robertson, Martyn Brabbins and Pascal from different perspectives in the stalls.

What came in between, alas, was a lot less enlivening. Considering the equipment Stockhausen then had to work with, Kontakte for electronic sounds (1959-60) remains a remarkably resourceful sound-montage. But the parts he added for piano and percussion – on this occasion the redoubtable Nicholas Hodges and Colin Currie – now sound dated and were often covered by over-loud projection of the electronics.

The real downer, however, was Cosmic Pulses (2006-07), from the Klang cycle Stockhausen was working on up to his death last year. Projected from giant speakers, this began with deep chimings circling round Albert's great dome. These soon speeded up to an excruciating tumult, with a deep, nausea-inducing rumble of lower frequencies beneath. Projected at deafening volume, it proved half an hour of near-torture.

The other extract from Klang was for solo trumpet: Harmonium (2006), a BBC commission receiving its premiere from Marco Blaauw. Comprising a sequence of melodies interspersed with muted echo effects, it reminded one how this master of futuristic sound resources continued to the end to harbour within himself a composer of almost touching naivety.

BBC Proms continue to 13 September (0845 401 5040)