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Marty Kasprzyk

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Everything posted by Marty Kasprzyk

  1. I wonder if the opposite also happens: "No matter how meticulous you are, you'll still run across the occasional fiddle that fits all the theories and still sounds lousy."
  2. Masking tape doesn't stop sound transmission very well so it is not surprising that the slots taped and untaped didn't sound much different.
  3. The walnut stain is a type of tannin and I would expect egg whites to cause it to precipitate and settle out quickly.
  4. Oh, I'm glad it's not just me! I wanted to show a radically different back plate arching shape of the viola I'm making and I couldn't post it.
  5. Yes. For red wines egg whites albumin (protein source) are used for absorbing harsh and bitter tannins. These tannins taste harsh because they are trying to turn the skin (protein) inside your mouth into leather. Tannins from wood are used for tanning leather. Red wine also often tastes smoother when it is served with cheese (protein source) because the tannins can react with the cheese instead of you. I have used pure food grade gelatin instead of egg whites. Hide glue would probably work too but I don't like the smell.
  6. Has anybody tried vacuum freeze drying wood? Water expands about 9% when it freezes. So if you first soaked your wood in water and then froze it and then pulled a vacuum to sublime the ice into vapor without melting it the wood's density might decrease. I anticipate that the wood's other properties such as elastic modulus, speed of sound, damping, strength etc. will either stay the same, increase or decrease.
  7. I think it wood make a good neck and fingerboard too. Attached are a couple of papers on bamboo for musical instruments. annurev.matsci.38.060407.132459.pdf 444108953_Bambooviolin.pdf
  8. If you wanted to make this settling process much faster you might want to try a fining agent used for clarifying wine, beer, and spirits. I use "Dualfine", www.ldcarlson.com It will take only a few days to settle out the sediment and it is very inexpensive.
  9. I have been recently unable to attach jpg photos. I used to do that often and I'm worried that I broke something in MN.
  10. I did indeed suggest making a stiffness overkill which would be then reduced to a stiffness moderatekill.
  11. If you think your back plate is too thin you might try stiffening it by gluing some longitudinal and cross direction wood bars on the outside surface to form a lattice pattern like what they with braces on inside surfaces of flat guitar tops. The bars could be something like 2mm wide and 10mm high with spacings of 20mm. You could play the violin as more and more bars are glued on (additive process) to see how the sound and frequency response curve changes. When you finish gluing on all the bars you could then shave their heights down (subtractive process) to again see how the sound changes. The bars could be evenly in height along their lengths or they could be tapered downward towards their ends like bass bars and the braces used on guitars. The outside braces can be completely shaved down to eliminate them and the process repeated (iterative process) until you are satisfied this was all a waste of time or when you finally like the results. If you do achieve something you like you can leave the braces on (for starting discussions with startled players) or you can shave them completely off and now repeat the process on the inside surface of the back plate so they will not be visible. 590788663_ScreenShot2021-07-03at10_37_56AM.png.pdf
  12. The most complete set of data I've seen came from: M.A. Pyrkosz, "Reverse Engineering the Structural and Acoustic Behavior of a Stradivari Violin", Dissertation, Michigan Technological University, 2013. http://digitalcommons.mtu.edu/etds/634 Pyrkosz took the CT scans of the "Titian" 1715 Strad to show in his table 4.23 that the top plate had a density of 0.35 g/cc with a weight of 48.1g and the back plate had a 0.570g/cc density and a weight of 88.9g. The plate thickness maps are shown in figures 4.69 and 4.70. With modal analysis of the various violin mode frequencies he was able to estimate the top and back wood's elastic modulus. I think it would have been easier to cut up the violin into wood strips and test the pieces.
  13. Do ou think we can make a humidity meter by measuring the tap tones of a violin plate?
  14. Is this before or after the varnish is applied? Joseph Curtin's data (attached) on old Italian plates had the tapped tones and weights for obviously finished plates. Tap_Routine_-_J_Curtins_Strad_article_06.pdf
  15. I'm sorry, should have said: "Some well established violin makers and researchers (Bilbao project team) believe that plate impedance (mass times mode frequencies) is important. But you are right-- some people always seem to disagree with other people's efforts. One term for this effect is "NIH"--not invented here.
  16. It can be argued that the plate tap tones and the plate weight are equally important. See the explanation at the Bilbao Project at the Basque School of Violin Making in Spain https://www.bele.es/en/making-tops-backs/
  17. Dunnwald doesn't show that the wood's aging has an important effect. He said: "The old Italian violins are good not just because they are old. There are many other instruments that are also old but they are bad, and there are many new violins that are very good." "The final results show that all groups of instruments (factory, hobby, master, old Italian, and new) contain very good violins, but the relative number is different in each group. The distribution of results of factory and master instruments is random, that of the the old Italian makers is not." "The reason for these results seems to be special knowledge among the old Italian makers." However I believe Dunnwald was "cherry picking" his instrument selection groups to show this. "One lot of instruments being known as having excellent sound (about 50 old Italian violins an others) was used as a reference group." But there are about 500 violins made by Stradivari that are known to still exist. You could do the opposite and pick the 50 worst ones and compare them with the 50 best modern violins and conclude modern makers had "special knowledge" that Stradivari didn't have and/or that old wood isn't as good a new wood.
  18. How do the frequency response of very old instruments differ from new ones?
  19. Put it out in the sun sometimes.
  20. Modern big grand pianos are louder than the small ones made three hundred years ago. But violins are still small little wimps-- therefore orchestras have to have many violin players to get enough sound. If you made violins louder you wouldn't need as many players and many of them would become unemployed and many violin makers, shops, and schools would also go out of business. That's why I'm getting death threats for making larger violins.
  21. What's the problem? Wood properties are all over the map and people's sound preferences are all over the map too. Violin making and selling is more like great dating matching than getting the right the crunching sound of Pringle potato chips.
  22. Apparently B.F. Phillips was a pretty good maker. In 1940 Jascha Heifetz tried about 100 American violins and selected the best four one of which was a Philips violin for comparison with a bunch Strads. Attached is a 1946 paper by F. A. Saunders which describes the testing. Saunders The Mechanical Action of Instruments of the Violin Family JASA 1946 copy.pdf
  23. So how does all of this affect the violin's sound?
  24. It is my expert opinion that one experiment is worth a thousand expert opinions.
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