Jump to content
Maestronet Forums

Marty Kasprzyk

Members
  • Posts

    3704
  • Joined

  • Last visited

Everything posted by Marty Kasprzyk

  1. I've made two octave violas and I found they sounded very nice but they were difficult to bow. Various strings are made with different density core and winding materials so it's more appropriate to calculate their mass per unit length M to compare them rather than their diameter. For example a steel wound string will have a larger diameter than a silver or tungsten wound string even though they have the same pitch. The mass per unit length M can calculate with: M= T/(4L^2 f^2) where T is string tension, L is string length, and f is the tuning frequency. The cello string length is about twice as long a viola's so with the same same pitch frequency and string tension your octave string has to be about four times heavier. Many string manufactures list their string tensions f for their different strings at their playing length L so their string mass per unit length can be calculated. You can then calculate your viola's mass per unit length for each of the four strings and then search for four strings that have four times that mass per unit length. I suggest using tungsten wound steel core strings such as D'Addario Helicore strings because they will have a small diameter which will make your bowing easier.
  2. DB might recommend using a Sawzall to do the scroll shaping.
  3. Different people like different things so there's a lot of scatter in preferences which means there will be a lot of scatter in the violin's physical make-up (wood properties, dimensions etc.) of what's liked. The VSA competitions use 3 tone judges who are well regarded players. Very few times will a violin get all three judges to like a violin and these are the medal winners. Violins often are liked by only one or two players. I consider these violins to be successful because at least some good players liked them. There are relatively few violins without any judge liking them. I've never seen it tested but I would bet three different good players-just by chance- would give different judging results. This makes finding a "theoretical goodness value" difficult.
  4. Lutheries who don't like numbers should get rid of their rulers and calipers.
  5. Jim Woodhouse has a good discussion on plate runout in his web site "Euponics" chapter 10 Wood: Properties and Measurement. See his figures 8&9. https://euphonics.org/10-3-wood-properties-and-measurement/
  6. Don't our own eyes create a similar relative size distortion effect? If I hold up something real close to my eye everything in the background looks small. For example if I hold my finger tip (20mm wide) a few inches away from my eye this computer screen entry looks real small and my fingertip covers half (100mm) of this page. But if I move my finger tip to touch this screen it covers up only about 21mm.
  7. Thanks, it's nice to know I'm not alone. I got rid of the shoulder rests, rubber bands, corners, chinrest clamps, tailpiece, chords, and end pins to make the instrument easier and more comfortable to hold and nothing falls off during playing.
  8. Please elaborate on what you mean by "easy to play (especially as regards to shifts)".
  9. Thanks for sharing your experience. Did you sense any difference in the instrument's weights? Were they all using the same make strings?
  10. I was a participant in an experiment at an Oberlin Acoustics Workshop about 12-15 years ago where we made incremental length narrow saw cuts ( I did the saw cutting so people could blame me afterwards for the impending wastefulness) alternating in increments above the upper eye of an f hole and below the the lower eye of an f hole in a simulation of what happens when various length cracks appear in these locations. Mechanical engineers (not train engineers) know that sharp corners produce stress concentrations that can lead to crack initiations. That is why f holes have their rounded tops and bottoms --these large radius shapes try to avoid cracks from starting. Nevertheless cracks still tend to start there because of the large load applied by the strings on the island area between the f holes. Much to our surprise the simulated crack saw cuts from the f holes actually improved the sound of this violin (a violin donated for the experiment which I wrecked and made unsalable). These cut were extended in a few centimeters at a time until they no longer showed an improvement in group listening tests. This might mean that cracks are not what be what they are cracked up to be.
  11. The problem with cracks in a violin top plate is that their opposing surfaces rub against each other to produce a nonmusical noisy sound. If you use a saw to make the cracks wider so that their surfaces don't touch each other then the violin actually sounds better than if it didn't have the cracks. F holes are just really wide cracks.
  12. If you are serious about wanting to make great violins I suggest this inexpensive book to help you get started: Bonnie Trachtenberg The Fine Art of Delusional Thinking: Happiness Means Never Having to Have a Reality Check
  13. Stewart Pollens suggested that the earliest violins had three strings tuned EAD and that later ones had an added G string. He described how that the length of the E string was as long as possible with gut strings while maintaining a factor of safety on string tension having one half tone of pitch. When designing new instruments one has to first chose what pitch range is desired. The early violins were developed to produce higher pitched notes than previous instruments. The length of the highest pitch string was determined by the breaking strength of the gut string materials. That gives the maximum tension possible which results in the loudest output possible. I've used Helicore viola steel E strings on a large 17.5in 5 string viola with a string length of 378mm. Stradivari couldn't have done this in his day. Early big instruments of the violin family (cello and bass types) were developed to produce low pitch notes and they had a much different problem. Their gut strings had to be real long to produce the low frequency notes because the gut material has a low density (~1.3g/cc). The only way they could have a high mass per unit length was to make them real thick in diameter which in turn made them difficult to bow and finger. They had high bending stiffness (not ideal) due to their large diameter so their overtones were not in a perfect harmonic sequence so they didn't sound very pleasing. Metal wire overwraps were eventually added onto the gut strings to greatly increase their mass per unit length which enabled shorter string lengths to be used which in turn allowed the large cello and bass instruments to be made smaller while the playability and sound quality improved. Thus experiments were done to increase the string length of violins and the string lengths of large instruments were made smaller. All of the above is well documented history. What we don't know is Stradivari's motivation to develop his long pattern violins and why he reverted back to only shorter ones. I speculated that it was due to gut E string breakage problems as a possible explanation. I think it should be noticed that he made long pattern and shorter ones simultaneously for a while. He didn't go short, then just long, and then back to short. Some Thoughts on the Tuning of the Early Three-String Violin STEWART POLLENS The Galpin Society Journal Vol. 64 (March 2011), pp. 61-66 (6 pages) Published By: Galpin Society https://www.jstor.org/stable/23209390 woodrow's length.pdf
  14. My theory is that Strad's long pattern violins originally had longer necks and string lengths. Longer strings would have to have higher tension if they are tuned to the same pitch. This higher tension would have increased the loudness of Strad's long pattern violins which may have been advantageous at that time (still is). But the higher tension would have also further increased the likelihood of gut E string breakage and players may have complained so he eventually went back to his shorter body violin designs with their shorter and safer strings. Modern steel E strings have eliminated this breakage problem so much longer strings can now be used. But we're pretty much stuck with using traditional size violins and string lengths.
  15. I've used two brands which worked equally well : System Three Clear Coat, and Alumilite Amazing Clear Cast Another one which I haven't tried is MirrorCoat bar/tabletop finish. All of these are available at Rockler stores. I bought the smallest kit available because you don't need much for a fingerboard. These epoxy coatings are very slow curing (about a day) to make them self leveling on flat horizontal surfaces like tables and bar tops. This makes it difficult to coat a curved fingerboard evenly with out dripping off the sides. So I put a masking tape dam along the sides and then coat the fingerboard just along its edges. After that has cured I go back and coat the center long area. The resulting epoxy layer is too thick and uneven in thickness so I then sand down the entire surface to eliminate ridges and thick areas with 150 grit sandpaper. If there are any dips of thin spots I then apply a third coating just in those areas. Finer and finer sandpaper is then used to get a polished smooth surface. A better method might be to slowly rotate the fingerboard like on a rotary cooking grill so the epoxy doesn't drip off the sides.
  16. I use a two part epoxy clear coating resin on my light weight spruce fingerboards. It is very hard and will probably never show any wear even with modern metal wound strings. If these epoxy coatings had been available a few hundred of years ago a lot of ebony trees would still be growing and the usual black color wouldn't be required which I find is rather depressing compared to other lighter colored woods. Reminds me of funerals and nuns. But for violins, a more important consideration than appearance, is the acoustic effect of different density woods. I don't know what the optimum is. Likewise for violas I don't know what fingerboard wood density gives the longest throw distance.
  17. He gave up because he couldn't buy long cases for them. Do the long body Strads use standard violin length strings or are they longer too.
  18. Meyer's reference is actually a 400 page book which you can download free at https://www.academia.edu/40662097/Acoustics_and_the_Performance_of_Music?email_work_card=view-paper Somel of the things you mentioned are discussed in his book.
  19. The amount of background noise between the note's harmonics influences an instrument's sound's character. I'm assuming a low amount of noise leads to a "pure" flute-like note sound. The attached plot shows the flute has less background noise than a violin. It was taken from "Acoustics and the Performance of Music" by Jurgen Meyer, Springer publisher, chapter 2.2.6 'Noise Contributions', page 33 It would be interesting to see if violins have differing amounts of background noise.
  20. Oops! I meant to say ...I've never heard of one that had a weight close to 77g. The frightening thing about my mistake was that I proof read this sentence three times before it was sent.
  21. The top plate thicknesses of famous old violins were all over the map but I've heard of one that had a weight close to 77g.
  22. If you are doing adjustment work it is helpful to have a French accent.
  23. Wine makers have a term called "cellar blindness"-- If you drink enough of your own stuff it eventually starts to taste good.
×
×
  • Create New...