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Marty Kasprzyk

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Everything posted by Marty Kasprzyk

  1. I would cut the eraser's excess height off and color it with a black magic marker.
  2. That's a good question. The traditional violin's lower notes on the G string aren’t very loud as shown in the old 1937 Saunders's tests of Strad violins (attached graph). If you like this (flaw, deficiency, idiosyncrasy?) then you should try to place the A0 frequency in the usual spot around 280Hz. Schelleng had shown in 1962 in his attached graph that the G string’s low frequency out-put was due to the low end tail (light line) of the A0 resonance was out of phase with the low end tail of the B1- resonance (dashed line) so the two vibrations cancelled each other as shown in the (heavy line). So if the A0 resonance frequency is rather high and close to the B1-frequency the lower notes will have a very low fundamental frequency amplitude and they will be weak and also not very deep sounding like a typical Strad violin. About a half century later in 2013 John Coffey (previously attached report)also noticed this phase cancellation effect between the tails of A0 and B1- resonances and he recommended: "Theory predicts a 180 ○phase change of sound radiated from the f-holes relative to that radiated from the top plate, as the frequency increases from below to above A0. Below A0 these sources interfere destructively, reducing the sound volume. This suggests that A0 should optimally be only a little above 196 Hz (open G) on a violin – say at A (220 Hz)." So I recently strung up one of my experimental violas with an E string to give EADG tuning like a violin. It has a low A0 frequency around 220 Hz like Coffey had suggested. Sure enough its frequency response curve did have a much higher responses from 196 to about 250Hz compared to one of my violins (see attached graph) and the Saunders loudness curves did show the viola have much better G string loudness (another attached graph) as predicted. So finally getting back to the original question of how close the A0 frequency should be to B1-? Forget all this stuff and just make them the same old traditional way so you can sell them.
  3. I agree. It takes a huge increase in the f hole area A to raise the A0 frequency. I think it follows the A^0.27 relationship that Bissinger found. John Coffey's 2013 paper (attached) beats this A0 subject to death. After 65 pages describing his carefully done experiments and analytical studies he concluded: "I suspect from these studies that the main function of the f -holes on the sound from a violin is simply to let the sound out – to allow the back plate to contribute to sound radiation and so give adequate loudness." But the wall compliance seems to have a big effect. Bissinger's translation (J. Violin Soc. Am.:VSA Papers 2019 Vol. XXXVIII, No.1)) of the paper by Hermann Meinel "On Frequency Curves of Violins" has a graph (attached) which shows how the A0 amplitude increases greatly as the plates are thinned. 609760676_JMC-HelmholtzResonance--Up-ct.pdf
  4. I agree --bigger f holes are better. Claudia Fritz (attached paper) found that it takes about a 20% change in A0 frequency to be even detectable. But If you change the amplitude of A0 it takes only about 10% change to be detectable. George Bissinger (attached paper figure 4) found the a big difference between "bad" and "good" violins was that good violins had a higher amplitude A0. One way of increasing the A0 amplitude is to increase the f hole open area. Thus increasing the size of the f hole opening might be a better way of increasing the A0 frequency (not very important) than decreasing the rib height. Fritz--perception of changes.pdf Bissinger, directivity.pdf
  5. Hi Anders, When Carleen Hutchins and John Schelleng designed and built the original set of their Octet instruments the A0 frequencies for their large bass, small bass, baritone, and tenor were all much lower than they wanted so they cut down their rib heights a lot to increase their A0 frequencies. I've plotted the % increase in A0 frequency vs. the % of rib height reduction which is shown in the attached graph. I've projected those four data points down to zero which is shown by the straight line which has a slope of 0.33 so one percent of rib height gives only 1/3 percent increase in A0 frequency. George Bissinger has later done considerable experiments on the AO frequency when the volume of an aluminum violin is changed by filling it with water to various amounts. He found the A0 frequency is inversely proportional to the volume to the 0.27 power. That is also plotted in the same graph as grey dots which is very similar Hutchins data projection.
  6. I don't like the sound of a violin's G string lower notes at all when the violins have a typical A0 frequency around 280Hz. I like the sounds of the lower notes on my viola's G strings better when the viola's A0 frequency is below 196Hz. So now I think a large viola with EADG strings sounds better to me than a standard violin. Ive been using Helicore long scale light tension viola E steel strings. From this I've concluded that the violin was originally designed for gut strings and short players with short arms and small fingers.
  7. The article's conclusion says: " The final, and probably the most important conclusion of this study, is the fact that variations in the material parameters23 can only be compensated by changes in the outline of the violin," That's not very helpful because the only outline changes that can be done are the ones to make the violin's outline smaller. The resultant violin still has to fit into a standard size case.
  8. The shaft of the Wittner pegs is knurled with fine ridges so the strings don't slip. Only a wrap or two of the string are necessary. I cut off a few inches of the string's end to greatly reduce the amount of peg turning which makes it much faster to do. A drop of super glue on the cut string end prevents the silk from unwrapping. I found it is best to put the glue on and let it thoroughly dry before installing the strings.
  9. Was anybody able to listen to the whole thing? I used to like Max Bruch. I felt sorry for the musicians playing the same thing over and over.
  10. I agree that an outside bass bar on the back should be very helpful. Make it real high and then shave it down to get where you like the sound. Decreasing the rib height requires a big reduction. Attached is a graph showing how the A0 frequency might change with rib height if you use George Bissinger's frequency dependency of the violin cavity's 1/volume to the 0.27 power relationship.
  11. I think some women shouldn't were yoga pants but I also think its admirable they don't care what I think.
  12. Maybe they had different ideas on what a violin should sound like and were working carefully.
  13. Wherever you put the A0 frequency may cause some notes to jump out and be louder than others. Strad's A0 around 280 Hz made his notes C# on the G string and the D and D# on the D string loud while his lower notes on the G string were quite weak as shown in the attached Saunder's loudness test. So if you like the big variation of the sound of Strad's low notes you should do the same thing. However your strong 264Hz A0 compensates for your rather low output in your 500-600Hz range and I would expect a more uniform note loudness than what Strad got. Some people might like it while others wouldn't.
  14. Has anybody ever shown in listener or player tests that a typical 280Hz is preferable to a lower A0 such as your 264Hz? I'd leave it until you find players don't like it. I'm guessing that some players might actually like it much better than all the other violins around. But if you want to raise the A0 there isn't much you can do to make a big increase. Opening up area of the F holes will give you only a few Hz increase. If you are willing to take the violin apart then adding vertical stiffening strips all a long the ribs will help. Cross braces on the top plate across the lower bout at its widest part can make a big change.
  15. Why do you want to increase the A0 frequency 20Hz? About 7mm lower rib height will give a 20hz A0 frequency increase. If you want that much of an A0 frequency increase I suggest you make the rib just a few mm lower and a little thicker, the f holes larger and the top and back plates also thicker and stiffer and/or a smaller violin. The three main variables are the instrument volume, f hole area, and wall compliance (flexibility).
  16. The angled tailpiece has been around for a long time. Attached is a photo of a 1742 Welsh crwth made by Richard Evans which is in the National Museum in Wales. The crwth history goes back about a thousand years and it was eclipsed by the medieval fiddle and the later violin. The bridge was flat so the strings were played as chords. Later instruments had curved bridges so that individual strings could be played. The later instruments also had narrow c bouts to give more bow clearance.
  17. Is a "knock test" the same as a "tap test"? My tap test is a fingernail tap to to the upper bridge edge on the bass side of my viola's bridge. I use Audacity software to get an fft curve. When I knock something it is usually a nearly empty beer glass with my right elbow. The sounds are quite similar.
  18. Doesn't putting in a loose sound post (low tension on the plates) differ in sound from one which is tight (high tension on the plates)?
  19. When you put on the strings and bring them up to correct pitch does the violin's frequency response curve change any way? Do the A0, B1-, B1+ frequencies all stay the same as the string tension increases?
  20. Here's a few more taken from the attached paper: JASA_Fritz_2012.pdf
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