True, I was thinking of the piano arrangement, but orchestral version is opened by a clarinet, and the player usually combines a glissando and a sizable portamento (and not having much woodwind experience, I have no idea how one would create that slide, like in opening of this classic recording http://www.youtube.com/watch?v=1U40xBSz6Dc)
That kind of slide involves subtly easing off the holes of the clarinet, leaving partial openings. It's a skill I practiced, but never really mastered. I could slide a few notes, but it was never make it that smooth, nor could I slide that many without easing off too quickly and making the slide "jump".
There's a bit of lipping it involved (especially across the 12th), but most of the secret is to drop the back of the tongue (usually somewhat arched) to open up the chamber of the mouth/throat and allow you to play with the resonance a bit. You'll usually hear that run with a bit more of a "wah" (I'm pretty sure I remember that being the official, technical term ^_^)to the timbre than is normal for a clarinet, tightening up into a more normal timbre at the top (where, honestly, fingering is mostly wishful thinking, and has less to do with selecting overtones than lipping does).
On a somewhat related note, the advent of MIDI and the subsequent wind-type controllers meant that I'd spent a whole bunch of money on a Lyricon the previous year for nothing...
Ah yes, I forgot about all the mouth-work that went into clarinet. It's been almost 14 years since I last played with any degree of seriousness. Thanks for the reminder :) It's starting to come back.
If you go to a 6th grade band class, to where the clarinet nd sax players are not adept at embouchure, choosing reeds and assembling the instruments, you hear all knds of interesting inadvertent things. Single reeds are fantastically flexible instruments. A few months ago i noticed for the first time how similar the tones of Dolphy's bass clarinet and Coltrane's soprano sax are on the 1961 recordings.
If anybody's interested, how to play quarter tone music on sax (pg 25 in the pdf:
