Don Noon

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About Don Noon

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    It ain't rocket science... it's more complicated
  • Birthday 03/20/1952

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  • Gender
    Male
  • Location
    Carlsbad, CA
  • Interests
    Acoustics
    Violin construction
    Varnish
    Old-time fiddling

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  1. It's impossible to judge how that giant gong "sounds" when it is just whacked at the edge by a tourist, as opposed to struck in the right place, and the right amount, by a gong master... as in the first video. He'd probably need a gigantic stepladder, though. A non-playing tourist would probably make the Cannone sound pretty crappy too, although there's no way the guards would let that happen.
  2. I have .30 Engelmann and .54 sitka (not torrefied). And there are probably wilder variations if you look long enough.
  3. A few confusing tidbits to keep in mind... 1) Trees can be hundreds of years old, so some of cellulose grown in the young years will be a lot older than the rest... but there doesn't seem to be any significant difference in properties between the old rings and new rings, other than the sapwood. 2) Lumber cut in thick beams or even moderately thick billets won't get much exposure to air circulation of the interior wood. 3) Wood 3 mm thick will have a LOT better exposure to air, oxygen, temperature/humidity variations, and light compared to either 1) or 2) 4) Old beams or trees, when cut and thinned, are optically translucent, vs. opaque for wood in old violins... something is different. (based on only 2 samples, but the difference is huge) So even if we DID have the weight of a wood sample 300 years ago, the environmental conditions of the wood might have more influence on the result than just the age alone. For sure, the environmental conditions in my torrifying chamber make a major difference. With a maple neck and ebony fingerboard at one end, and chinrest at the other, I agree. And tests confirm. That is why I use denser, stronger wood for the endblocks. The violin corners move significantly in some modes (particularly CBR), so I keep the cornerblocks light.
  4. I haven't used balsa, but there's some .29 density spruce that I use for corner blocks. That's getting close to balsa.
  5. There may be a third market (the one I'm designing for): a viola soloist that wants more response, power, projection, and clarity to be heard over an orchestra. These qualities are not normally associated with the viola, and I think are attained more easily with a smaller size. It might be objectionable in a quartet setting, where the violinists wouldn't want the sonic competition.
  6. Yeah... you might dent it if you touched it.
  7. Linearity briefly means that restoring force is proportional to deflection, in all mode shapes. Using a string as an example, it will be linear if the tension is constant. For a steel-core G string, large deflections cause the core to increase in tension, thus the string frequency rises when there are large deflections... so it can go slightly non-linear. I'm not a gong engineer, but somehow the huge gong in the video was made specifically to have non-linearities that cause energy to bleed out of the low-frequency mode into the higher modes. I don't think that wolf notes, adjustments, or bowing variables are any indication of non-linearities in the violin structure, although there could be some non-linearities in the bow/string interaction.
  8. I determine wood density and stiffness in the billet form, so taptones and stiffness of the plate are somewhat redundant determinations of wood properties. I could probably just use calipers and a scale to finish the plates without much (if any) loss of consistency. A little lighter for high stiffness/weight wood, and a little heavier for the denser wood, and be done with it. Without the predetermined wood properties, then I'd want to see the taptones and/or absolute stiffness in order to know what I'm working with. I use all of that stuff now, but I don't need it all.
  9. The long fixture supports the plate at the end blocks (for longitudinal stiffness), and the other one supports the plate at the corner blocks (for crossgrain stiffness). Then there's the dial indicator and 1 kg weight, and surface plate. Like taptones, it's pretty quick and easy to make a measurement and record it... and it so far hasn't yielded any valuable secrets. A thickness caliper and scale would probably do just as well, without all this other stuff.
  10. The key is "linearity of the system at the operating point". If it's non-linear, like the gong, then you can get all kinds of strange things going on, including influences from static loading. As far as I know, nobody has demonstrated any non-linearities in the violin structure vibration, nor significant influence of static loading on vibration behavior. I know folks might bring up soundpost tightness to refute this statement... I'd love to see some objective results and analysis about this, but up to now all I have heard is anecdotes with no physics-based explanation (it's on my long list of things to do, but not near the top).
  11. If by "performance" you mean modulus, then for sure yes. If you mean speed of sound, then most likely yes. If you mean radiation ratio, then there's almost no way. If you mean some acoustical evaluation of the final instrument, then I have no idea what you mean. That means bending stiffness of the plate as carved. Many experienced makers flex the plates by hand to judge this. There's such a long time between instruments for me that I wouldn't trust my judgement about this, so I have a couple of fixtures to support the plate in different ways and measure deflection with a given load.
  12. Can you imagine how much work it would be to carve 43 grams of wood out of a violin, just to get it down to the weight of the Cannone? I suggest a Hacklinger (or modern electronic equivalent) gage to see where the weight is. Certainly the back plate would have to be most of it, unless something very odd was done (like pliers).
  13. I doubt you are going to be happy... My opinion is based on a lifetime in aerospace engineering, as well as a couple of decades of attention to violin acoustics. More specifically, there is no theory or evidence that string tension does much of anything acoustically to the violin body, neither does the minuscule variations in string tension during vibration... which is how I read much of your theories. If you have any tests or evidence to back up your theories, fine... but diagrams and verbal arm-waving won't do it for me, as it just looks far off the mark.
  14. And will continue to be, every time there is a post regarding physics that I disagree with.