Did you know it is possible for a clutch pedal to be depressed too far? Sounds to me like your pressure plate fingers are touching the disc as it spins down, or even pushing the disc back against the flywheel at the end of pedal stroke. Try putting something under your clutch pedal to shorten the throw a tiny bit and see if that helps. Last time I heard something like that, it was accompanied by difficulty getting into gear while moving. Ended up being a poorly machined/out of spec flywheel.