While one may argue that the act of recording improvised music
can take away from what is only supposed to be a one-time performance,
Century Quartet does it anyway, only to show examples of what can be done
in a freely improvised setting.
Recordings are done as a 2 track stereo mix
directly onto hard disk, then transferred straight to any audio medium.
Since each performance is recorded, in a 3 month period Century Quartet can
produce over 3 hours of new pieces. You can get recordings
at Rasputin Music in Berkeley.