If you like that, check out Nina Perlove's rendition of The Great Train Race by Ian Clark(e?) on Youtube, just search her name and you'll come to her performance and teaching videos on youtube. Totally awesome, and utilizes extended techniques like this guy does; it's a really neat piece.
Poor quality flutist? It takes a lot of training and practice to flawlessly execute the techniques they're doing. It's the flute played as it's not traditionally heard.
<Added>
I love the beatboxer guy, Greg, too. Though I'd never beat my flute like that, it seems to work for him lol
I myself have not gotten to this level of music with all the extended techniques and crazy avant garde stuff... but from what I have read, there are typically notations telling the flutist what technique to do while playing the notes, such as flutter tonguing. There's all sorts of slashes and abbreviations to drive yourself nuts with
Check out Larry Krantz's totally informative site. http://www.larrykrantz.com/et/et.htm
There are links to listen to just what the heck they're talking about along with brief description of each technique.
While some of them sound just a little wacky, there can be benefits to learning or experimenting (which is what I stick to lol). For example, singing while playing is a technique in and of itself but it is useful for throat tuning and relaxing the throat area by being aware of it. I find that I sound really strong and centered after dabbling in it a few minutes.
searching...
