NCH Kevin Barry Room

Feldman – For John Cage.

Ravel regarded the violin and the piano as instruments which really didn't go together, and when he wrote a sonata for them he wanted it to reveal what he called "their incompatibility".

Morton Feldman's For John Cage, the 75-minute-plus violin and piano piece he wrote for a John Cage 70th-birthday celebration in 1982, separates the instruments even more, by calling on the violin to exploit the intonational range that allows it to play notes that literally don't exist on the piano. The piano is limited to step-by-step pitch changes, but the violin can also work, as it were, between the cracks.

For John Cageis not just long, it's also slow and soft, written in that micro-gestural style which Feldman so thoroughly made his own. Paul Zukofsky, the violinist for whom the piece was written, has offered the metaphorical explanation of Feldman's music as being not just concerned with cells and cellular processes, but also "in bonding and molecular structures".

Feldman addressed the issue in another way. "Up to one hour," he said, "you think about form, but after an hour and a half, it's scale. Form is easy – just the division of things into parts. But scale is another matter. You have to have control of the piece – it requires a heightened kind of concentration. Before, my pieces were like objects; now, they're like evolving things." The National Concert Hall's Kevin Barry Room is of an intimate size that might seem ideal for the music of Feldman. But it wasn't designed for concert use, and there are regular noises off from traffic on the street and intrusions from passers-by in animated conversation.

Tuesday's performance of For John Cagewas given by the experienced duo of Darragh Morgan (violin) and John Tilbury (piano). But the music felt strangely lifeless. Yes, Tilbury's quite brightly-lit piano tone contrasted starkly with the almost feeble delicacy of Morgan's heavily-muted violin.

But there was, paradoxically, very little tension, microtonal or otherwise, between the two instruments. The necessary tension is actually quite small, like surface tension in a glass of water. On this occasion that tension was somehow undermined by the musical equivalent of a surfactant. And the bigger picture just didn't hold.