Xenakis held degrees in both music and architecture. I love the music but I wonder if his obsession with architectural form prevented some of the compositions from having a "warmer" feel. This obsession seemed to become more pronounced as he got older, and his later works (especially the vocal stuff) suffer from a lack of non-mathematical elements. I wonder if this wasn't a trap, a trap that some of his contemporaries (like Ligeti) didn't seem to fall into.