MIMF

I can neither play nor build violins, and am not about to argue with those who can, but I'm a bit confused. When I enter the values given for cavity volume and "port" area, guessing the plate thickness to be somewhere between 2mm and 3mm, into some online Helmholtz resonance calculators
here
http://hyperphysics.phy-astr.gsu.edu/hb ... ty.html#c4
and here
http://www.vk2zay.net/calculators/helmholtz.php
I get frequencies between 800Hz and 900Hz.
I imagine that body shape and hole placement has something to do with it, but it's still a huge difference. Blowing across the sound holes seems like a perfectly good test. When I did the same thing with compressed air and a guitar, it practically bounced off the bench!

You might contact the Catgut folks. Their library is at Stanford University. https://ccrma.stanford.edu/marl/CASL/CASLhome.html

One thing I forgot is that port length, which I assumed to be the plate thickness at the sound holes, should include the "end correction", which accounts for the mass of the air moving in and out of the holes. Assuming the measured frequency is correct, and that Helmholtz got it right (safe enough), solving for L gives 2.6 cm. Also, the calculator assumes simple shapes, and violins are anything but, so I suppose this is reasonable. I feel much better now.

Hi Barry,
It seems like testing a new fiddle against an old one is like testing new wine against old. I think they do get better with age when properly cared for.