Sunday's fascinating promotion by BCMG of the Neue Vocalsolisten Stuttgart raised an important issue which perhaps we don't consider enough: the balance of quality between performance and content.

Here we had a brilliant sextet of vocal virtuosi, putting their immense talents at the service of music which, in at least one case, was well past its sell-by date and which, in others, raised the question why bother?

In terms of sheer sound, the most successful offering was Petrrohl by Georges Aperghis, its schizophrenia-derived subjectmatter going for nothing delivered via unintelligible text, but its hyperactive sounds rendered by these astonishing musicians like a busy string sextet.

The music's restless pulse was impressively maintained, as was pitch with no instruments beyond the occasionally-deployed tuningfork to help, and balance between the individual voices over a wide range of dynamics was utterly remarkable.

Salvatore Sciarrino, a composer I have previously admired for his fastidious ear, was here represented by his L'Alibi della Parola, an effetely Orwellian vision which drew upon medieval chant (as so many Italian composers do) to add perspective to its overladen emotional baggage. There was, however, a nice little scherzo with pinging vocal pizzicati from the performers.

The visual comedy the sextet provides was rewardingly deployed in Lucia Ronchetti's Anatra al sal ("salted duck"), which had the performers vying with each other over the best way to cook a duck, each of them restricted to one vowel sound: " con pomodoro rotondo rosso monocromo" sticks in the memory.

Luciano Berio's impossibly dated A-Ronne, so archly "clever", obligatory references to Dante, liturgicalism and all, belied its "radiophonic" origin in this engagingly slapstick presentation, before a crooning, swooning Brahms "Lullaby" encored us happily home.

Christopher Morley