Video 1 Helmholtz slip-stick illustration

Video 1.         Helmholtz string wave excited by slip-stick mechanism of moving bow (University of New South Wales, courtesy of Joe Wolfe).

 

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Video 2.         Visualisation of empty shell modes in vacuum before opening f-holes or adding bass bar. Ribs are transparent to view back plate vibrations as well as top.

Video 3.         Empty shell modes with open f-holes at twice normal  ambient pressure. The circular disc moving up and down represents air flowing in and out of the f- holes.

Video 4.                    Shell modes without bass bar but with a 20 mm offset sound post to illustrate asymmetry of resulting shell modes and coupling of breathing mode to previously non-radiating modes