Free improvisation is music made spontaneously without regard to an underlying structure. It's also code for "pretentious made-up twaddle" by unsympathetic music critics for anything that's too crazy for them ― i.e. Colin Stetson's Judges ― regardless of accuracy.
Why is it called that?
Though improvising exists in numerous forms of music, it was during the 1960s that genre underpinnings of jazz, classical and electronic music melted away and created a need for new terminology. Nowadays, rock and noise improvisers are ascendant.
Who's doing it?
There's pretty much one club/loft/basement in any mid-sized town where it's happening. Check out labels like Ambiances Magnetiques, Barnyard, Drip Audio and Inyrdisk for Canadian sounds.
Where should I start?
Nihilist Spasm Band's No Record, AMM's AMMusic, Polwechsel & Fennesz's Wrapped Islands, the Thing's (pictured) Bag It!, Arthur Bull and Daniel Heïkalo's Concentrés Et Amalgames.
You joining in and making your own racket.
Check out our Free Improvisation playlist on Rdio here.