I don't really know what it is either. Nice article a couple months ago in the LA Times, with pics of some really weird looking dudes who play this music then go burn down churches or something. Sounds like my kind of people (I'm being bold, here, I'd probably run from them as fast as I could if ever confronted).
Anyway, there's this guitarist around town, Gentry Densley, who I've heard play free jazz, noise music, and all sorts of other stuff (did a stint with SLAJO as well). He's been in a bunch of groups, I suspect a web search would reveal much more depth.
Occasionally he shows up with a distinctive presentation, my favorite was the basement installation of 12 tube amplifiers at max volume with a guitar or bass in front of each putting the amps into total feedback. Arranged in a circle, this created quite a cacophony of sound. Actually, probably not a correct description, more like a giant roar!
Ken Sanders Rare Books hosted another presentation, this a shortened form of his latest group, Ascend. Just guitar (heavily modified) into a couple amps, with a drummer. Whatever he played, very heavy, suggested the Norwegian Black Metal image I got from the LA Times article.
Check out the Ascend CD at: http://www.southernlord.com
If I were at my real machine, rather than stealing time at work, I could post a picture of the show. Maybe next time. I'm still learning this blog thing, lots of possibilities but I never have what I need when I need it. Sounds more like a condition of life!