New York-based, dedicated to performing contemporary string quartets and making their London debut on the final weekend of the Wigmore Hall season, JACK Quartet come with an immaculate pedigree. They have studied with the Arditti and the Kronos Quartets, who, over the last two decades, have stood at the forefront of the contemporary quartet repertoire. JACK's own excellent reputation preceded them, too, thanks to their CD survey of Xenakis's string quartets released two years ago.

There was Xenakis in this Wigmore programme, too – his Tetras was the last of three 20th-century classics that made up the bulk of JACK's programme. Alongside them was Matthias Pintscher's Study IV for Treatise on the Veil, from 2004, part of a series of works inspired by Cy Twombly's paintings. Like so much of Pintscher's music it makes the right kind of modernist-chic gestures, in this case a tracery of skeletal, spidery sounds – harmonics and tremolos, often on the threshold of audibility. They are apparently inspired by the techniques of Twombly's works, but really add up to very little.

It was delivered, though, with the kind of unfussy intensity that JACK seem to bring to everything they play. In Ligeti's Second Quartet, they combined meticulous care in realising every inflection and colour with a perfectly judged sense of the work's scope and stature. Cage's Quartet in Four Parts was guilelessly beautiful, like a series of renaissance madrigals bleached of their expressive dimensions. The Xenakis, though, was an epic tour de force. Tetras welds the instruments into a single, snarling entity, with fearsome technical challenges; yet, as well as the physicality, what emerged here was the musical structure, thrillingly conveyed.