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Final check before starting varnishing

posted 4 Jan 2015, 04:16 by Peter Grankulla
It is advisable to set up violins in the white for fine tuning of B1 modes. As I have done this several times and already know how this violin reacts, I feel confident and moving straight to varnishing procedure. Starting with UV box for color (tanned wood reacts with casein/lime ground)

For the record this violin did not need re-tuning from the outside. The back plate is almost perfectly tuned and graduated. Strong middle and c-bout edges (C2 is 402 Hz). The top is most critical as it is very sensitive to chin rest setup. I'm not sure exactly why but I think it might be a combination of bass bar optimization and reverse graduation of upper and lower bouts (thicker around edges). I use to think that small lower end block is the most influential parameter. This is not the case as I have tested several chinrest clamped in different position. B1- can go down as much as 20 Hz with some chinrests.

The modes before varnishing (MC 5-6%, Humidity 33%)

Tuned fingerboard; underside hollowed out reversely to get B0 down, 4,5 mm upper and 5,5 mm at the end 450 Hz. B0 without FB is 250 Hz.

without/with FB (attached with tiny blue tack dots, not advisable without experience, should be temporary glued)

B1-    456 Hz/449 Hz (blue tack damps this mode)
B1+   542 Hz/531 Hz 

I will adjust the final frequencies with varnish.