I've been trying to figure out what the strange squealing noise Joe makes in some of his songs is, an example of what i'm talking about is 0:32 in Satch Boogie

It sounds like some kind of whammy harmonic, but i'm brain dead, so I ask the magical internet people.

Any ideas?

Muchas gracias
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it's either a pinch harmonic or a natural harmonic in the 2nd or 3rd fret
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he does a pinch harmonic on an open string, which effectively gives the same note as a natural harmonic on the second or third-ish frets.

i know that's how he does it. actually DOING it is extremely difficult
Satriani effectively performs a pinched harmonic on the open string of usually the B or G string (sometimes both). Before doing this, he usually depresses the strings so they are slightly lax, or the opposite, and raises the whammy bar so the strings are tightened. He then reaises (or lowers) the bar to vary the pitch and give that cool harmonic screech.

If your looking for examples, youtube a satch performance, he does it in most.

If you like Dream Theater and have bought the special shiny version of Systematic Chaos and got the DVD with it, watch Constant Motion. Petrucci does the same technique at the end of his solo (which is of course, is insane... )
dump your bar slighty with your left hand, pick wiht your right and quickly/lightly touch a part of your picking hand on the bridge side of the neck pup. Then raise the bar. Turn the gain up a tad and select ya bridge pickup. Shouldnt take to long to find it. I think that squeal is on the G string.
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