[How to further thicknessing this back plate for violin]

I’ve measured the frequencies of violin backs and then measured the frequencies with the ribs glued on and I found consistently Mode 5 goes down but Mode 2 goes up.

Very interesting Guy, Thanks for putting this up. I was curious on what happens to the modes when ribs are attached. I'm also interested in how these are predictors of resonances of the fully assembled violin.

Do you measure Q in any way? Resonances are one thing, but I suspect that a strong resonance will have a different effect then a weak one, and I'd like to characterize this.

If you subscribe to plate tuning for specific modes, Jonathan Rowe has a couple diagrams on his site on adjusting modes somewhat independently. Based on the CAS journals. I’ve tired it with some success.

Stephen

[casein/oil emulsion]

I was experimenting with emulsions on the weekend. My own experiments found that Casein/Oil worked well. In my case I was using JOHA varnish.

My own test samples showed that the Casein/Oil mix had similar optical results as Vernice Bianca. I also tried a Vernice Bianca/Oil emulsion with similar results. Noteably, I am hand mixing which may have impacted the results. I'll post some pictures later today for the curious.

Should I expect better results from Casein/Oil or is it similar optically and superior acoustically then just using Vernice Bianca as a ground.