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Marty Kasprzyk

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Everything posted by Marty Kasprzyk

  1. I witnessed Anders Buen testing a violin in a fully ceramic tiled men's room to ensure that all of the violin's directional sound was reflected back to his single microphone set up on a tripod to ensure he was capturing all of the violin's directional sounds. The violin sounded great when he played it. This was done as a quick and cheap alternate method to using many microphones surrounding the violin in an anechoic enclosure. (Bissinger used 266 microphone positions in a spherical array in his tests) I don't recall the results of Anders' violin tests but I do remember people's surprised expressions when they came in to take a piss.
  2. Random size books on shelves are good sound absorbers and nicer looking then polyurethane foam cones of a anechoic chamber if you are trying to eliminate a room's ringing resonance sound effects and only want to hear what the violin sounds like. It also suggest you like to read.
  3. I use water based Minwax polycrylic clear gloss finish on my MDF inside molds. Long also I also used it for finish on my spruce top plates and maple back plates for my violins and violas. Unlike other varnish- ground systems it did not change the tap tone resonance frequencies at all after it was applied. Apparently it was adding stiffness and mass in exactly the same ratio as the base wood had to start with so it had no effect. I thought this was great benefit until I realized that I was increasing the plate's impedance by adding stiffness and mass--the resonance frequencies were staying the same but their amplitudes were decreasing thereby reducing the sound output. So if you are making MDF plates be careful to use only a light coat of polycrylic finish.
  4. The plant leaf is way ahead of us violin makers. You might like the book "Plant Biomechanics, an engineering approach to plant form and function" by Karl Niklas
  5. I use "clear" Gorilla glue. It has a much longer setting time which gives ample time to make sure everything is correctly positioned. I also use it for gluing my bridges down. However I do use super glue for hardening the string bridge's notches.
  6. How about putting the thin superglue just on certain plate areas to stiffen it just there. Maybe you could kill wolf notes that way. I recall you mentioning putting dimples in metal plates to stiffen them in areas where the vibration was too high.
  7. I suspect maple is used for the back plate because it is a poorer sound producer than spruce so that more sound will come off the top plate than the back plate. MDF is not as good a sound producer as maple thus it should be an even better back plate material.
  8. Bending stiffness is proportional to E not E^1/2. I'm getting stiff in my old age and I should do more bending stretches.
  9. You could adjust the longitudinal and cross grain stiffnesses to duplicate various woods by cutting grooves in the MDF plate with your cnc machining (subtractive forming) or by gluing on ribs (additive forming) like they do in guitar building.
  10. How did it sound and play? I believe a high amount of damping isn't necessarily bad--it should reduce note starting and ending transients which would make fast passages less blurred and it should reduce wolf notes.
  11. I forgot to also predict the amplitudes of the signature modes will be higher.
  12. It will sound great. All of the signature modes will be lower in frequency and closer together which will give a rich lower end sound. The high end will probably be normal. The only problems are that it isn't traditional, looks too plain, it will soak up a lot of varnish and wood dealers will put a price on your head.
  13. I don't think cardboard is so bad and I've always thought it can be superior to solid wood. A corrugated cardboard can have a higher stiffness/density, strength/density, and higher speed of sound/density ratio than solid spruce because the empty channels mimic the longitudinal porosity that wood has on dense cellulose but with an even greater effect. However I don't think it is a good idea to use wet cardboard just as it isn't a good idea to use wet (or green) wood. Of course this doesn't mater for violas.
  14. There are many varieties of red and white wine grapes and there is some overlap in their wine flavor characteristics so it is not possible to identify with certainty in a blind test whether or not a wine is red or white. For example I colored a good chardonnay white wine that I had made with tasteless red grape color extract and I was able to "fool" two dozen experienced wine tastes in a blind red wine taste that it was a red wine. I didn't really fool them--it just tasted like some of the red wines that they've had in the past and they just thought it was another one. In this case my chardonnay had some toasted oak wood exposure which is often also commonly done with many red wines. The opposite can also happen. This weekend I had a well made oaked pinot noir red wine that I could have easily thought was a chardonnay in a blind white wine tasting. So the issue isn't about identifying what it is but rather whether or not it's any good. Wine tastes can very reliably identify bad, mediocre, and good wines because there are big differences between the groups. However the differences between good and great is much smaller and individuals have different preferences so there won't be full agreements. Our preferences also are subject to change depending on lot's things. One way of beating the inconsistency of judging between small differences is to use many judges which is what Claudia Fritz was doing in her blind violin testing.
  15. What are the acoustic differences between flat top and arched topped guitars? What is the advantage of an arched top guitar?
  16. It's in good condition because nobody liked playing it.
  17. I've made the bad mistake of making easy to play & sweet sounding instruments and hoping good players would like them. This is similar to expecting mountain climbers to like Kansas.
  18. A good player once told me he played his Strad violin seven years before he began to like its sound. I asked him why he stuck with it so long and he said it was very difficult to play so it forced him to become a much better player. I replied: "If your goal is to become a better player you should use one of my violins."
  19. The sharp corners of the saddle cut out act as stress risers which is where cracks often originate. A better design has rounded corners and even better one is if the whole cut out has an elliptical shape rather than a rectangular shape.
  20. The comparisons of musical instruments and the human voice have been going on for thousands of years. See the attached article "Voicelikeness of musical instruments: A literature review of acoustical, psychological and expressiveness perspectives" Voicelikeness.pdf
  21. Yes, strings have improved but a I still feel that 1/10 cello with a 17.75inch (45m) body length doesn't sound or play as satisfying as a similar size viola.
  22. You're welcome to borrow one of my violas if it would help sales.
  23. That's what I suggest too. If you like playing vertical instruments a large viola with an end pin is easy to play. If you're playing for your own enjoyment then I suggest a Carleen Hutchins "Tenor violin" which is between a viola and cello in size and is played one octave below violin tuning. Bob Spear at Singing Woods Violins makes modern versions of them. I think it's a mistake to have really small fractional size instruments played with normal tuning. Their short strings are heavy and hard to bow well.
  24. When something breaks it means either the part isn't strong enough or that the applied load is too large. Early string instruments often had flat top plates and they had low bridges with a shallow curvature. These were suitable for playing multiple strings at one time for chords but as music evolved there was a demand for single note playing. This required higher bridges with more curvature which enabled a single string to be played. Narrower C bout widths helped give more bow clearance. The higher bridges made the string angle over the bridge more acute which increased the downward load on the the top plate. The flat top plates were no longer adequately strong so makers started to use stronger and stiffer arched plates to better resist this string downward load. Thus the sound character of the instrument then followed the increased strength and stiffness requirement. Arching increased the stiffness with little increase in mass so the result was higher resonance frequencies resulting in a brighter but less mellow sound. This was obviously successful and all our violins, violas, cellos and basses now use arched top plates with their sound character. But an alternate path of reducing string loading could have been chosen centuries ago. My instruments use a shallow string angle (~168 degrees instead of about 158 degrees) which decreases the downward string load on the top plate by about a half. I've also adapted the ancient (12th century?) Welsh crwth instrument's design which uses only one bridge foot resting on the top flat plate. The other foot rests on the sound post which goes through a hole in the top plate so this foot's force goes to the back plate rather than the top. This obviously also reduces the string load by a half so the total downward load is only about a quarter of a normal arched plate instrument. The tailpiece is also integrated with the fingerboard so the string tension load is not applied to the instrument body. This eliminates the longitudinal load on the top plate which is a contributing factor in conventional arched plate buckling. The end result is that a flat plate top can survive. Anyway, I'm following the road not taken.
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