some fantastic music mentioned here – dead c, terry riley, of course reed’s metal machine music always gets a mention.
i write an experimental music blog in my spare time – OBLADADA. i suppose stuff like roland kayn’s scanning or a little electronic milky way of sound are genuinely challenging although i absolutely love them.
merzbow, gaseneta, fushitusha and les rallizes denudes can blow folk of their feet a bit as well with some wild japanese savagery. i suppose its what you like and i geniuely am drawn to what many folk see to find unlistenable (my wife for example).
for me, unlistenable is music that actually causes that weird second hand embarrassment. so music thats so hideously cheesy to make me squirm. top loader, lighthouse family, simply red and m-people are just a few masters of that oeuvre.
give me atonal jazz, strobing minimalism or alien electronics over that rubbish anyday…