Joanna MacGregor and Arve Henriksen bring Deep South blues and Scottish Reels to the Southbank

It's not often in classical music that the performers themselves are the main focus of our attention; more often than not they are at the service of the composer. But this evening was an exception to the rule, showcasing the multi-talented Joanna MacGregor and Arve Henriksen. In the absence of a conductor, the musicians performed with a great sense of rapport throughout, ably directed from the keyboard by MacGregor.

The concert began with the hushed, ritualistic opening of Arvo Pärt's Fratres for strings and bass drum with claves. In his tintinnabuli style (literally 'little bells'), Pärt writes remarkably effective music using very little material. From the subdued opening, the homophonic string texture grew more impassioned with each refrain. This was such an atmospheric performance that the applause had the effect of a broken spell, confirming Pärt's assertion that 'it is enough when a single note is beautifully played.'

The next two works by MacGregor and Henriksen themselves fused a variety of styles, with mixed results but always fascinating, for I had no idea which musical direction they would take next. Here the two musicians showed us the full range of their abilities as both composers and performers.

Described as a 'sound innovator', Arve Henriksen plays the trumpet like no one else. He has cultivated a flutey, silken tone that though at first was a little disconcerting, often had a highly emotive vocal quality. He was perfectly matched by MacGregor's smoky piano chords for the opening of Lost Highway, a work that draws on gospel and blues as well as music by Tom Waits and Nick Cave. At times the music had a driving quality that suggested the endlessness of the American highway, using piano riffs and percussive string figures.

Most effective was Lowside Blues (known to some as an ABRSM Grade 7 piece), arranged here for piano, trumpet and solo violin. The instruments seemed to transform themselves in the manner of a chameleon, the muted piano strings recalling bass guitar while the trumpet provided a low, percussive impetus. Thomas Gould's elastic violin solo had a raw, liberated approach that was present throughout the piece, epitomised by the tinny 1920's recording of two children singing Everybody Help the Boys Come Home. The main problem here was that sometimes there were just too many ideas and overly lush orchestration - a more judicious balance would have been welcomed. The four pieces by Henriksen opened with a spoken work recording that spoke of travel, people and places, punctuated by gamelan-like bells. Then a laid-back looped drum motif fused with silvery strings while Henriksen improvised a solo, also using a piccolo trumpet and guttural vocal cries. This was soulful playing but ultimately there was not enough variety to distinguish the different movements and hold our interest.

From American blues to Scottish jigs, James MacMillan's Piano Concerto No. 2 brought a much needed contrast, drawing heavily on folk music as part of a ballet score. This was an altogether more boisterous work, opening with a vigorous string unison and 'snap' plucked bass, alternating with more elegant, ornamented interludes from the solo piano. In between the murkier episodes was a playfully deliberate waltz in the manner of Strauss, with MacMillan often toying with a faux-sentimentality. Other humorous episodes came in the form of a Henry Cowell-esque 'clusters' episode that simultaneously obscured and made a mockery of the main theme.

The finale 'Shamnation', was a riotous reel, at times delightfully bonkers as it evoked drunken festivities with whooping from the orchestra members. This culminated in a remarkable athletic display of pianism. MacGregor dispatched muscular palm clusters whilst maintaining the spirit of the reel, ending with a sweet smile as if it had all been child's play.