I only heard this type of sound once at a Warehouse Rave, back in 93, but have never forgotten it.
This forum would be the only chance of finding out if anybody else has indeed heard "the Rave quack"
The quack takes the place of the usual bass beat once the tune peaks and has a rough frequency of 3khz
At times,- it's pitch is slowed down and only then does it's complexity become apparent.
The closest analogy of the slowed down sound would be a cross between Donald Duck's voice and an air raid siren that is barely turning over.

Very interested if anybody knows of tunes with this type of sound.
Who knows- maybe i was just hearing things that were being distorted due to "other influences".
Thanks.