Marty Kasprzyk

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About Marty Kasprzyk

  • Rank
    Enthusiast
  • Birthday 06/02/1945

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  • Gender
    Male
  • Location
    Olcott, NY, USA
  • Interests
    Wine making, gardening, dog training,

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  1. Marty Kasprzyk

    Materials shelf life resource

    The climate conditions are important for shelf life. Ideally for long storage you should have a constant humidity and temperature to minimize any air leakage through the container's seal. I would love to have a wine cellar. In the mean time I drink it exactly as fast as I can make it.
  2. Marty Kasprzyk

    Viola Bashing

    I'm hearing many players saying the same thing. Some like the sound of big instruments but end up using something smaller and easier to hold. The largest stress on a player's shoulder is proportional to the longest distance the left hand is extended times the instrument weight it has to support (torque). Viola proportions aren't standardized so there are many combinations of body, neck, and string lengths. Therefore a more accurate measurement of instrument comfort is the distance between the nut and the saddle's edge.
  3. Marty Kasprzyk

    Why arching shape?

    I'm not trying to duplicate an arched soundboard--I'm trying to do better. Of course I will fail, but to paraphrase lord Tennyson: It's better to have tried and lost than to have never tried at all.
  4. Marty Kasprzyk

    Why arching shape?

    A while ago I got the idea of exploring why flat tops aren't used from George Bissinger's paper (attached) which discusses the consequences of in plane and out of plane movements in arched plates: "Why not just make a violin with flat plates where IP motions are negligible? The obviously effective compromise reached three cen- turies ago resulted in arched – not flat – plates. We might wonder why?" 0707biss.pdf
  5. Marty Kasprzyk

    wood selection

    A violin making friend of mine (now deceased) gave me a piece of very old red cedar which I used to make a new top for one of my violin teacher's damaged ancestor's instruments. The wood was very crumbly and difficult to cut and scrape cleanly. He thought it sounded wonderful and I was proud that he chose it to use in his very last concert before he died. I know it is wise not to jump to conclusions based upon just one data point but using cedar frightens me.
  6. Marty Kasprzyk

    Why arching shape?

    I believe some of these modal analysts were done with just a one axis accelerometer in the vertical direction which shows the motions only in the up and down directions. As a consequence it appears that the edges do not move sideways in or out as the plates bow up and down. If a 3 axis accelerometer or laser vibrometer had been used you could also see the edges moving sideways in and out (in plane, IP) in addition to up and down(out of plane, OP) at low frequencies. These IP and OD movements are shown in the drawing that I had posted earlier and attached again here. Since sideways (in plane) motion of the top plate is different than the back's the entire violin body will bend along its length as seen in Colin Gough's attached illustration. But this body bending motion doesn't produce much sound. The top and back plate's up and down motions create cavity volume changes which do produce sound through the f holes. George Bissinger believes the up and down to sideways movement ratio (OP/IP) gives important insight to a violin's output from the front and back directions. Attached is one of his papers which discusses the testing of the Titian Strad and the Plowden DG violins. Since Colin's illustration indicates that the in plane motion IP is proportional to the arch height squared (from hypotenuse rule) it follows that the the in plane motion is reduced by reducing the arch height. Further since the body bending doesn't efficiently produce sound it further follows that a low arch height increases the low frequency sound output of a violin. I suspect this caused the trend over many years towards lower arch heights for violins that soloists preferred. If you project this historic trend and modern analysis and testing evidence to an extreme you could conclude that a perfectly flat top should produce the loudest possible sound output. This is why I make my top plates flat. And why I'm accused of being an extremist. ASA 153rd Meeting Lay Language Papers -3-D Motion in Stradivari and Guarneri dG Violins - Netscape.pdf
  7. Marty Kasprzyk

    wood selection

    I very much agree that something is missing. I'm beginning to feel that too much emphasis has been on violin's sound character and not enough given to playability issues. Great players want several things but many studies have concentrated on only the easy things to measure. It's easy to do measure a violin's sound spectrum and to do listening tests for liability or projection in halls. On the other hand it's expensive (laser vibrometers, impact hammers) to do admittance tests and minimum & maximum bow force tests that relate to how difficult it is to play an instrument or mold the violin's sound. The results of those kinds of studies then have to be related to the violin's structure for us makers. I thought Pyrkosz (1) was making real good progress but unfortunately he graduated and took a job completely unrelated to violin research. That's a problem--there's no money in doing violin research. Much of the work is done by graduate students or professors and there's only a few of them in the world interested in violins. The students go on to other things and the professors are retiring. 1. "Reverse Engineering the Structural and Acoustic Behavior of a Stradivari Violin", Michael a. Pyrkosz, 2013, Dissertations, Master's Theses and Master's Reports, Michigan Technological University
  8. Marty Kasprzyk

    wood selection

    What ever it is, it might help to have a lot of it all the same.
  9. Marty Kasprzyk

    Why arching shape?

    I like the sound of the Chinese Erhu better than a violin thus a flat stretched python snake skin is better than an arched wood plate. Florida has a problem.
  10. Marty Kasprzyk

    wood selection

    In the near future I think we'll see what the wood properties are in great violins. The procedure will be to do a high resolution CAT scan of a violin to get the exact plate geometries; a modal analysis will be done, and then a finite element analysis model will be made with the geometry and guesses for the wood properties. Many iterations of the FEA will be done with successive different material property guesses until all the predicted mode frequencies converge and match what the real ones are. The capability to do this already exists. It hasn't been done because it requires a lot of effort and there's no money to do it. I'll gamble and bet that the great violins were made with rather ordinary wood.
  11. Marty Kasprzyk

    Glue for Tropics

    Maybe that's true for violins but I've never had a viola sink because its Gorilla glue center joint failed.
  12. Marty Kasprzyk

    Why do bridges bend?

    The bent bridges I've seen always were bent with the cup towards the finger board. I speculate that the strings and/or the tail cords gradually stretch and retuning the strings causes the top of the bridge to be pulled towards the fingerboard. This suggests that the choice of string core or tail cord material might be playing a role in addition to the bridge wood quality. For example a nylon tail cord with nylon core strings might be more prone to bridge warping than the newer synthetic materials or steel. Maybe in the southern hemisphere they bend towards the tailpiece.
  13. Marty Kasprzyk

    Why arching shape?

    There is indeed some of Janito's drawing "A" spreading of the C bout cross arch as seen in Colin's first illustration which is attached. I suspect that the corner blocks might help reduce this spreading compared to cornerless violins.
  14. Marty Kasprzyk

    Why arching shape?

    Attached is a finite element analyis (FEA) modeling of a violin under string tension taken from Colin Gough's reply to Mr. Zulger a few years ago. It shows how the back is statically stretched longitudinally more than the back and how the end blocks are rotated inward and how the top plate is dished downward. If you look carefully you should see that the C bout cross arch flairs outward. After a long time wood creep will eventually make these shape changes permanent. I've also attached Colin's entire reply. Influence of static tension and differential in-plane displacements breathing mode.pdf
  15. Marty Kasprzyk

    Why arching shape?

    Both things happen at the same time. The ribs bend to accommodate the outward movement shown in "A" above and the arch is pushed downward as shown in "B".