Iannis Xenakis had a natural affinity for numbers and mathematical 
                  concepts. His relationships with musical instruments were a 
                  little more complex. His works for solo instruments usually 
                  fit under the fingers, but their idiomatic qualities are rarely 
                  based on a deep understanding of the repertoire. Xenakis also 
                  had a perverse interest in creating technical difficulties for 
                  players to negotiate. And you don't do that by just writing 
                  lots of notes, it takes a real understanding of what is possible 
                  to play and what is not if you are planning to position your 
                  music squarely on the border between the two. 
                    
                  The works on this disc span the second half of the 20th 
                  century and give a taste of every period in Xenakis's career. 
                  The quality and interest peak in the 1960s and then go into 
                  slow decline. The most famous work on the disc, and deservedly 
                  so, is Nomos Alpha written in 1966. This is one of his 
                  greatest masterpieces and by any estimation deserves a place 
                  among the top few cello works of the 20th century. 
                  The mathematical principles on which it is based are derived 
                  from successive projections of a rotating cube. Or at least 
                  I think that is what's going on; the liner notes are mercifully 
                  vague when it comes to the technical end of things. But you 
                  don't need any knowledge of maths to enjoy this. As with many 
                  of Xenakis's string works, Nomos Alpha calls for heavy 
                  scraping on the strings and includes lots of tremolo glissando. 
                  So the music is always in a state of flux, either from the continuously 
                  changing pitch or through movement across the continuum between 
                  noise and sound. The technical challenges here are just extraordinary. 
                  At the end, for example, the cello plays a series of scales 
                  in contrary motion on artificial harmonics. The mind boggles 
                  trying to imagine the contortions the cellist's left hand must 
                  go through to achieve those. 
                    
                  None of the other works on the disc quite match this opening 
                  track for invention or originality. The two tracks that follow 
                  - Charisma for cello and clarinet and Kottos again 
                  for solo cello - are unremittingly aggressive. Xenakis chooses 
                  performance techniques that are going to produce the most abrasive 
                  sounds and pursues them doggedly. There is musical interest 
                  to be had here, but it takes some work.  
                  
                  Epicycles for cello and 12 instruments is similarly unrelenting. 
                  The block chords from the brass here resemble those in Eonta. 
                  That work succeeds because the lack of rhythmic interest in 
                  the brass is more than compensated for by the piano. Here the 
                  solo cello line also lacks rhythmic invention, as if the composer's 
                  interests lie only in his harmonic elaborations. Interesting 
                  as they are, they don't make up for monotony of rhythm and orchestration.  
                  
                  
                  Roscobeck, a more recent work from 1996, achieves an impressive 
                  feat by combining cello with double bass and coming up with 
                  a range of musical textures and ideas that justify the pairing. 
                  The high quality of the sound reproduction helps to clearly 
                  articulate these bass textures. The balance is kept even down 
                  at the bottom, with no extraneous bass amplification, all the 
                  better to admire these strange timbral combinations. 
                    
                  The programme ends with an early work, Dhipli Zyia. This 
                  shows another side to Xenakis, one that is closer to Bartók 
                  than to the post-war avant-garde. The piece never quite breaks 
                  out into a folksong but always feels like it is about to. 
                    
                  No great technical challenges on this last track, but by this 
                  point cellist Arne Deforce has earned the right to rest on his 
                  laurels. The cello playing throughout is excellent, especially 
                  when you consider the astonishing challenges the composer sets. 
                  The cellist, his various collaborators, and the sound engineers 
                  all make a good job of the brutal noise-like textures, and the 
                  sound of the cello always has a visceral immediacy, even though 
                  the microphones are usually placed a reasonable distance back. 
                  
                    
                  The first track of this disc is more than enough to recommend 
                  it, and the endless fascination of Xenakis's score repays multiple 
                  listenings, especially with a performance and recording of this 
                  quality. The other works are only likely to be of interest to 
                  already committed Xenakis fans. Although if you really want 
                  to get your head around the relationships between higher mathematics 
                  and Modern music, this would be a great place to start.  
                  
                  
                  Gavin Dixon