Regarding recommendations for CDs of music by Xenakis:

On Erato 2292-45771-2 "Idmen" & "Pleiades" are performed by the Choeur
Gulbenkian, directed by Sylvio Gualda. These are for percussion ensemble.

On Hyperion CDA66980 "A Colone", "Nuits", "Serment", "Knephas" & "Medea"
are performed by the New London Chamber Choir, Critical Band, conducted
by James Wood.

There is also, I understand, a recently released 2 CD set of various
pieces on the Ultima label (of music that originally appeared on the
Erato label), but I don't actually have that set & I don't yet know
the full details myself.  Some other knowledgeable soul may have that
information ready to hand.

Geoffrey Gaskell