Thanks Jack! I listened to a bunch of those, and must admit that some of them do have nice "pitch". Some don't (not that that's bad) and they're all closely miked so the mouth resonance is more pronounced than in real life. There's some real artistry there though and I feel compelled to go back and listen to the rest of them later.
From an acoustical viewpoint the spring remains the same pitch throughout and the mouth changes resonance. This is much as one would do on an old fashioned synthesizer when running a tone through a VCF (voltage controlled filter), but of course much more rich.
Back to the topic. I remember working in a music store and there was some pressure to drop the "jew" and shift to "jaw". I'll go along with what is socially acceptable as there's no need to make a scene when some people are sensitive - or overly so. That discussion is better had in a place like this. However, I don't think it is a good idea in general. I respect the history, and don't feel we have to carry forward the negative things which in reality are long gone. In short, I don't think we are liberating any Jews by changing the name of this little instrument.