[Confucio]

Listening to the modal works by John Surman i suddendly found this video of an improvisation with maqamat (arabic modes):

I wonder how they achieve this raw timbre that remembers me some mediterrean/eastern europe folk instruments:

 

[ismail]

Uhm. I don't hear a "raw timbre" in the first video! And the second one doesn't include a sax.
Do you mean something like this:

there is growling involved. humming a note while you are playing. especially effective on higher notes.

 

[Confucio]

No, I mean something more like that (from 0:00 to 0:56)

 

[ismail]

Well that seems to be false fingerings or, more specifically, multiphonics. Don't ask me about that but you can get one (!) sound that is similar by closing all keys except for the G key.