Interesting links, Mark.  The "tap tone" site is surely the result of a huge amount of time and investigative / experimental work.   Oddly enough, I have already set myself upon a small project over Xmas / New Year to investigate "natural body resonances" of the violin (specifically, my monstrosity, "Herman" ) - but I most certainly won't be going into as much depth as Langsather has done - that sounds like a lifetime's work - I'm just looking to identify specific resonances and not necessarily try to correct/adjust them.

Yup, interesting links, thank you !