Having missed a chance to hear Conlon Nancarrow’s Player Piano Study no. 21 (Canon X) due to a spontaneous programme switch earlier in the day, I was delighted that Dominic Murcott’s arrangement of the piece for London Sinfonietta and player piano opened this concert. The piece is predicated simply on an upper voice beginning very fast and slowing down, and a lower voice beginning slowly and speeding up so much that the final 12 seconds of music contain no fewer than 1,028 notes. For an ensemble to tackle two simultaneously occurring tempi is extremely difficult, but the solution for this arrangement worked brilliantly. Two Baldur Brönnimanns, one conducting the upper voice, the other the lower, appeared in a pre-recorded video projected for all to see. Apart from this making the players able to follow their scores, this was visually stunning and neatly outlined this simple musical process that produces this extraordinary effect. This music could not be called beautiful: its harsh edge and counterintuitive process is not for the faint of heart, but it is captivating, and a musical experience like no other. This is the piece that first drew me into Nancarrow’s eccentric world, and Murcott’s arrangement made me glad to be there.

Nancarrow wrote two pieces for small orchestra, the first 42 years before the second, and these are among the very few indications we have of Nancarrow’s aesthetic outside the world of his beloved player piano. There remains much to recognise – a harsh timbre prevails through this piece. Oboe and trumpet take much of the melody, often unusually supported by solo violin playing in unison – an effect to make orchestration tutors cringe, but that reasserts Nancarrow’s music as operating outside any stylistic convention. This is both a difficulty and a charm of his music. The trick is to simply submit to his will: accept that this will be an unusual listening experience and the rewards are plentiful. This piece made the most of Brönnimann’s crisp conducting style as melodic lines are clinically passed around the instruments of the ensemble before being systematically stamped out. John Cage greatly admired Nancarrow and this piece made it easy to hear why; its cold approach to the material and sharp contrasts of texture and mood is very reminiscent of Cage’s orchestral music.

Yvar Mikhashoff’s arrangement of Nancarrow’s Player Piano Study no. 5 rounded off the opening salvo of pieces, and was the highlight too. This piece has a simple bass line that isn’t quite the ostinato that it seems – the rhythm is just off-kilter, changing its proportions constantly, and the repeating pattern of pitches is never quite the same. Add to this the not-quite-recognisable scales in the upper voice, and the effect is of a demented piano student struggling through a test. Put into ensemble this effect is softened, and through delicate orchestration this was a beautiful rendering that turned the bizarre character of the original into an exotic palette.

John Cage’s Five was performed consummately by part of the ensemble, and in its focus on static but shifting sounds made good sense in the programme, as we then reached James Tenney’s Spectral Canon for Conlon Nancarrow. ‘Spectral’ music, which explores the timbre of a particular chord or pitch, really needs to be heard live for the effect to come off and so it’s a shame that outside of France this music is rarely performed. Tenney’s piece created a magnificent atmosphere as wisps of sound illuminating the spectral characteristics emanated from the performers. This is technically demanding music requiring control and agility, and was performed terrifically by this impressively versatile ensemble.

After the interval Rex Lawson, pedalling the pianola, and Alexandra Wood, playing violin, performed Nancarrow’s Tocatta for violin and player piano. More than anything, the piece demonstrated the performance practice of the pedalled pianola in an ensemble setting, something new to me and that made me realise the more intricate and subtle side of the pianola. Of the responses and arrangements to Nancarrow’s music, none stand out more than Dominic Murcott’s arrangement (for toms and woodblocks) of Nancarrow’s only piece for tape. Nancarrow was obsessed by layering different tempi and used automated means of production in order to achieve the incredibly complex tempo relations that result. Therefore, to see percussionist David Hockings produce this performance by human production was astounding. Head stock still, his body pulsated and contorted in all sorts of ways, freeing up his limbs to act entirely independently of one another as the rhythmic counterpoint of this music demonstrated his incredible technique.

By the end of the concert, and following a full day of Nancarrow, I was glad of some silence – but this was an impressively performed, well conceived, and well curated concert that mixed the curiosities, interest and pure beauty of Nancarrow’s music with a surrounding programme to place it in context. Arrangements and responses served to demonstrate the influence Nancarrow exerts over contemporary musicians. This Southbank festival allowed Nancarrow dorks a good dose of what is rarely performed, and introduced those new to Nancarrow to music unlike any other.