Marty Kasprzyk

  • Content Count

  • Joined

  • Last visited

About Marty Kasprzyk

  • Rank
  • Birthday 06/02/1945

Profile Information

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

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Marty Kasprzyk

    The importance of varnish

    That all makes sense to me. I'm just suggesting the fine filler particles shouldn't have a high density to reduce plate weight gains so it doesn't have much acoustic affect. If colophony rosin (density of only 1.03g/cc) powder was first rubbed on the wood surface it would fill the pores and prevent subsequent deep varnish penetration. Colophony rosin has an index of refraction of 1.541 which is probably similar to various oil-rosin varnishes so it might not have any negative optical effects. Rosin powder is inexpensive and commercially available.
  2. Marty Kasprzyk

    Houshold LED lights than don't strobe? Does anybody know of any?

    A DC power supply would be more convenient than a battery. If it had adjustable voltage you could adjust the color temperature and spectrum.
  3. Marty Kasprzyk

    The importance of varnish

    One of the justifications claimed for using a ground layer is that it reduces the amount of varnish that would fill up the wood pores. The density of mineral fillers is probably in the range of about 2.5 to 5 g/cc depending on what kind of ground up rocks you're using. The density of various organic materials and hardened varnish is around 1.1 to 1.2 g/cc. So a mineral ground would probably add a lot more weight and change the various vibration mode frequencies and amplitudes a lot more than simply using a pure organic ground-varnish system. I don't see any acoustic advantage of using a mineral ground.
  4. Marty Kasprzyk

    Houshold LED lights than don't strobe? Does anybody know of any?

    Would an old fashioned incandescent bulb with a rechargeable battery (old car headlight) give reduced flicker?
  5. Marty Kasprzyk

    String tension and afterlength

    The pitch (f) of a string is dependent upon the string's length (L) from the nut to bridge, the tension of the string (T) and the string's mass per unit length (m) with the following "Mersenne equation": f =(1/2L)( T/m)^0.5 The pitch of the string's after length follows the same equation. The tension T and the mass per unit length m stay the same so the pitch is higher due to the afterlength's shorter length.
  6. Marty Kasprzyk

    String tension and afterlength

    No. The tension at a given pitch is independent of the afterlength.
  7. Marty Kasprzyk

    Houshold LED lights than don't strobe? Does anybody know of any?

    When I do an Audacity fft test on my iMac with its internal microphone I always get 60 and 120Hz spikes.
  8. Marty Kasprzyk

    The importance of varnish

    You nailed it! It took me about 15 years to realize when somebody said my instrument was "nice sounding" it was actually a bad insult but also a graceful exit for the player. Now I specialize in making terrible sounding instruments. Players love them because then they can show off all their amazing skill.
  9. Marty Kasprzyk

    Tailpiece Grain Direction?

    Should the curvature of the tailpiece also match the curvature of the bridge?
  10. Marty Kasprzyk

    Planetary geared pegs

    I have one (1) Wittner cello peg you can have free. That should bring the cost down. I use Wittner pegs on all my violins and violas and like them a lot. However some good players (Nathan Giem, one of the VSA tone judges for example) don't like them because their pitch adjustment movement is too fine. It's amusing to see players reach for the tailpiece string adjusters and not find them.
  11. Marty Kasprzyk

    The importance of varnish

    Martin Schelske's work on how various ground and varnish systems affected the wood's speed of sound and damping loss factor was very carefully done and thorough but I think he didn't emphasize some of his results enough (see page 39 "level difference"). If you look at his figure 7b you will see that the admittance (related to how loud an instrument might be) decreased with one of his varnish methods. An overall decrease of 2.6 dB up to 1500Hz is a lot of lost output. Consider his sandarac varnish in Figure 3. It increases the speed of sound only about 1% and doesn't change the damping at all. You might conclude that using this varnish wouldn't change anything. However the speed of sound c is dependent upon the square root of the elastic modulus divided by the density. Since the varnish coating is very thin the thickness of his test bars is essential unchanged so the speed of sound for his samples is proportional to the square root of the ratio of the sample stiffness S to its mass M: c = (S/M)^ 0.5 So if you increase the test bar's stiffness and weight nothing happens to the speed of sound and all the various mode frequencies and sound character should stay the same. You might say this varnish is rather benign. However if you increase the stiffness and also increase the mass the impedance i or resistance to movement (reciprocal of admittance) also increases proportionately to the square root of their product: i ~ (SM)^0.5 So adding a lot of varnish can reduce the violin's output even though the sound character might not change. Please notice that the output is decreased with the stiffer heavier example even though the damping didn't change any. Quite often we blame a decrease in output is due to an increase in damping when in fact an increase in stiffness and mass is the culprit. So the advice to use a minimum amount of varnish is still correct but some times for different reasons. Schleske did this excellent work 20 years ago and it has been bugging me ever since. I haven't talked about it all this while. Maybe I should also say some things to my ex-wife.
  12. Marty Kasprzyk

    The importance of varnish

    I think the microphones are too close. If you were hearing this seated in the hall it would sound more mellow.
  13. Marty Kasprzyk

    shop lights.

    Maybe violins look best and sound best in candle light. Other things are better too.
  14. Marty Kasprzyk

    The Title for this item made me laugh!

    I had always thought that "points" were the sticky-out projections on "corners". So you can have a cornerless violin or a pointless violin with corners. They are not the same.
  15. Marty Kasprzyk

    Violin Bridges Can Be Confusing!

    They would get a better sound if they cut in some string notches.