Anders Buen

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About Anders Buen

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  • Birthday 06/03/1970

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  • Location
    Oslo, Norway
  • Interests
    Violin-, Hardanger- fiddle-, room- and architectural acoustics.

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  1. Superglue on bridges can do wonders. :-) How about f-holes in the back plates as well? The first «see through» fiddle.
  2. Maybe if the MDF is "varnished" with thin superglue, it might stiffen up a little again. The eyes will hurt a little from the fumes.
  3. The MDF plate data given in our resource for building material and "how to" information are classfied in different densities and hardnesses from 500 kg/m3 to 900 kg/m3 with the highest E-modues for the densest plates. There are softer plates too down to 250 kg/m3 used in floors or as wind shield with some asphalt in them. All of these have in general higher E-modules, when dry, than Maple crossgrain in average. I look at Haines data then which is a small data set (n = 22) with a few Yugoslavian data points. Average along grain: 11152 +/- 2635 [MPa], Across grain: 2029 +/-548 [MPa] G
  4. Yes, I just saw that in the book too and was about to correct myself. The compressional wave speed has the E-modulus under a root sign. The bending stiffness for a flat plate goes as the thickness cubed.
  5. Ok, I must have misinterpreted.
  6. Ok, thanks. Your slab cut back competition instrument was a viola then?
  7. I think the Strad sample sounds better now with my headphones than from the IPad. It sounds like a rounder and fuller violin sound than I originally thought. Pretty even too. Maybe it is a fairly great instrument after all, also tonewise.
  8. A decent violin. It does sound a little "mickey mouse" in the highs. Laser cleanish. I like the lows, the G string seems very fine. Pretty even and bright violin, I'd say. She moves the bow to and from the bridge, and play with a tilted bow, also a tone shaping thing, britghter I believe. Playing closer to the bridge too. The mic may be at a distance, as we do almost not hear any bow noise hiss. May be the reason why the higher notes sound a little narrow and almost too clean. The celloes sounds crisp.
  9. I guess you are right on the slab-cut wood maple data. Your memory is probably fresher than mine on that. I have been working on OSB strand plates lately and have the responsibility within our company for the plate data we use in our building acoustic prediction models for sound insulation and impact noise. But you did not answer my real question, though. The effect of slab-cut backs on the spectrum. The E module influences the flat plate bending stiffness under a root sign, so a 60% change of the E gives some 77% of the original bending stiffness. Almost within natural variation, if
  10. My experience with slab cut backs is that the B1+ mode tend to lie lower in frequency than it will in normal cut ones. I am sure you have measured your slab cut back insturment and know how that came out. The crossgrain strength is a bit weaker, and it thus becomes more isotropic than the normal maple plate, I believe. In general maple is more isotropic than spruce to begin with. I think the MDF is quite a bit less stiff in the longitudinal direction. But failry similar for the sideways direction. I may have to look this up, though. And MDF plates can vary too in their properties. With th
  11. Is this both your violin and daugther, Don?
  12. Maybe similar to what a slab cut back will do?
  13. Or his wife or female players cryed so hard when playing that the mascara with alum floated all over the instrument.
  14. Using the lightest possible material for a test of a substance is the best method of getting results. The changes are likely to be dependant on the surface mass of the test object and the added mass sortof like 20log(m+dm) if the m is small you easily get effects. If the mass, m, is larger, like 2,5mm spruce, the effect is likely to be very small. After reading about the wide use of alum, even today (eg in deodorants and cosmetics), I think it is plausible or not impossible that it can be found on old or even new wood or in the varnish.