Oded Kishony

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About Oded Kishony

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    Central Virginia, USA

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  1. Effects of rib height

    I can't speak to phase relationships per se as I've not measured them, however in my experience selectively thinning the ribs can have a dramatic effect on tone. In the past I mistakenly thought that the ribs themselves were radiating a lot of sound but the theorists seem to have shot that down, so now the explanation for the change in sound is to blame the plate adjoining the rib section involved. The effect is the same the explanation has changed-a common occurrence in the violin world. oded
  2. Ever kick anyone out of your shop?

    I find it very annoying if someone shows up at my shop without an appointment. It's disruptive and rude. I don't recall ever kicking anyone out but when someone arrives unannounced I can be mighty surly. I did have one customer who bought a viola from me and had already paid half, but he made me so crazy that I returned his money and took back my viola. ok
  3. Effects of rib height

    I've been present at a number of experiments with rib height as well as having tried a range of rib heights on cellos. My conclusion has been that, all else being more or less equal, higher rib heights on a cello tends to result in a more diffused sound while lower ribs tend to improve 'focus'. I've never observed an effect on loudness. And I've not observed an overall effect on tone quality, presence or absence of overtones, tone color etc. Oded,
  4. Low pass filters?

    You might have more success dealing with high frequencies if you search for high frequency 'clusters' rather than trying to identify specific modes. You can do this by running a frequency analyzer on 'continuous' (peak hold helps) placing a microphone close to the surface while tapping with a fairly hard striker (hammer). You can actually use a plastic computer mic and strike the surface with the mic itself. You will see the frequency range change as you move around the surface. At some point you will see that mostly the higher frequency range is active. Oded
  5. Origin of Smaller Cellos

    Oh OK, I thought you were commenting on the players and knew something I didn't. These small cellos seem to be losing their popularity. I've made quite a few of them and they are extra challenging (IMO) as they tend to be more tenor than bass. Isn't there also a Rogeri small model? I seem to recall John Terry making those for a time. Oded
  6. Origin of Smaller Cellos

    I don't judge...;-) ok
  7. Origin of Smaller Cellos

    Stradivarius had a narrow 'ladies' model cello. A famous example of which is the 'De Munk', performed on by Feuermann and more recently Steven Iserliss. Oded
  8. Ease of Sounding Resonances

    Most violinmakers in the US were taught the German style of making, that is to make the individual parts and then assemble them. If you are accustomed to finishing the violin from the outside to begin with, then listening to string response while you're doing it is a very small change. Yes, the varnish does change the sound, but by sealing the instrument and becoming very familiar with your varnish's tonal properties the 'problem' disappears ;-). I think another issue for modern violinmakers is that it's all too precious anymore. The Italians were craftsmen, artisans, albeit very talented and smart, but at the end of the day, they needed to produce quickly and efficiently and since they competed with each other they needed to have the best sounding violin on the block. Another reason BTW for not finding any published records, I'm sure some of these methods were closely held secrets. Even if you are trying to follow a Cremonese model for building violins you may still want to tap and or weigh you plates because you still need to decide when to stop graduating them. But you need to aim for a slightly over built instrument since more wood will be removed from the outside. BTW In my experience the total weight loss after the edgework is completed is between 5-8%, not an insubstantial number IMHO. Oded
  9. Spirit varnish hardness.

    I bought it as 'shellac wax' from a reliable source. oded
  10. Ease of Sounding Resonances

    What Wm Johnston says....but you evidently missed my point that this could all have been an integral part of the making process and not a separate part. Unless it was deemed that the particular instrument had a problem and therefore requires further work. In my own making, if an instrument sounds very good I don't bother with any final adjustments. Yes, I believe that some of the tool marks found on Del Gesu's instruments were part of his voicing process. These tool marks may have been more or less invisible in the new instrument until the varnish started to wear when the peaks lost more varnish than the valleys. Regarding Mr Beard's point that there is a dearth of written documentation. There is no shop manual of any kind that has been found from the time and place for building a violin. No varnish recipes either, we are left to deduce what was the most likely process. The criteria I use to decide if a method is a reasonable explanation for how the Cremonese approached their work is first simplicity, efficiency, artistry and finally physics. Oded
  11. Spirit varnish hardness.

    I have a 30 year old chunk of shellac wax that's turned hard as a rock and crumbly. This is not a wax that stays soft indefinitely. Oded
  12. Ease of Sounding Resonances

    The assertion was made that the Cremonese would have had very limited specific acoustical information regarding their instruments. My comment was meant to challenge that notion. In my experience the contemporary acoustics community would find it demanding to plot nodal lines for multiple frequencies on any given location on the violin, yet this was/is possible (easy) to accomplish without electronics, computers etc. You ask why do it? Possibly for the same reason some people do modal analysis or FEA or spectrum analysis, or study various archings, models, graduation schemes etc etc. But to give you a more concrete answer. If, for instance, the G string on your violin seems weak, not focused or doesn't project well and you've concluded that the sound has too much fundamental and not enough harmonic overtones, you can search the surface of the instrument for G string harmonics by damping the other strings, tapping the surface with a hard object (to stimulate the higher frequencies) then chase down the harmonics of the G string. Scrape, that area while still listening to the vibrating string (because many things change simultaneously while you're scraping) After which you can play it and see if you've accomplished your end. While all this seems very fussy on paper, IMHO it was mostly accomplished during the final finishing of the instrument and seamlessly integrated into the Cremonese construction method. As further circumstantial evidence; the observation that some Cremonese instruments seem to retain their voice despite having been regraduated etc. If subtle variations in the arch were part of the construction, those elements would not be destroyed by regraduation. That's not to say that repairs, doubling of edgework, pressing out of arching etc etc does not have any effect on the sound but it seems to me that enough of these original acoustical elements remain to preserve the tonal qualities on some of these historical instruments. Oded
  13. Ease of Sounding Resonances

    Yes, but locating nodes and anti-nodes on multiple frequencies isn't quite that easy. ;-) ok
  14. Ease of Sounding Resonances

    True, we know almost nothing about Cremonese acoustics. However, I would not make the assumption that it was impossible that they were unaware of resonant frequencies, nodal areas and anti-nodes. Needless to say, their understanding of these phenomena was different from ours. It is entirely possible to accurately identify all these things utilizing the bi-directional property of strings and the corpus. In the same way that plucking or bowing a string causes the corpus to vibrate, tapping the corpus starts the strings to vibrate. Tap the corpus on a nodal area and the string stops vibrating. It's that simple. And since the Cremonese most likely finished their instruments from the outside, (see Sacconi, Hargrave Hill et al) it is not inconceivable that the instrument was strung up while they did this and the scraping of the surface caused the strings to vibrate. Having a string suddenly stop vibrating surely caught their attention. Oded
  15. spiral bushing material?

    I've used a variety of different papers as well a different types (thicknesses) of archival quality Tyvek. I made a matched set of delrin mandrels with corresponding tapered holes. I wrap the material around the mandrel then tightly press it into the hole and leave it until the glue sets then remove it to allow the bushing to completely dry. Sometimes it's useful to insert the mandrel in through the narrow end to be sure the tapered end gets compressed enough after first installing the bushing. I know of one shop that's been using paper spiral bushings on their rental fleet for a number of years and have had no unusual problems associated with the material. In my experience paper grabs the pegs where maple bushings can sometimes get too slippery. Oded Kishony