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Anders Buen

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Everything posted by Anders Buen

  1. Then would I beleive it? There is already be a software provider investigating if one of my ideas for extended use of their program can be inplemented. May or may not turn into something.
  2. I think we are as different as possibly can be, only the age and some interest in violin making is common, possibly some education. I would never ask anybody if they were interested in hearing my professional history. But many males I know tend to listen for a few seconds then they start talking about themselves and their own ideas. I think that may be a mild kind of personal disorder or simply persons who need somebody to listen to them, because they do not have enough support on that side in life. Or it may be a dominance thing.
  3. I’m not. Do not need it, nor am i curious.. Our room acoustic program use graphics and originally a program language. Im pretty good at that, in steps. If we need something we will pay attention and be curious.
  4. E.g. underwater sound is processed using any possible means to identify the sources in military and intelligence applications. There are acoustic mines, stuff imitating a given sub or surface vessel to lure the enemy. Or makle things explode at a decoy rather than a real vessel. In human intelligence voice recognition is a big "above surface industry" for forensic work, intelligence or whatever. We are good at it with out brains and trained listening system. I have a collegue who made her master thesis on an AI network for identifying birds. There are studies in bioacoustics where they try to figure out how mice, rats and other guinipigs thrive in the lab by their ultrasonic and sonic vocalisations. My point is that there probably are numerous aplications out there which can investgate the violin and the player using AI. The bioacoustics example is a commerically available program based on a PhD. I think it is easier to figure out and identify the player than the instrument. But I do belive it is possible also to identify the instrument at hand, maybe also across players.
  5. Sorry that I did not answer all q’s. I guess only no 1 was adressed. The v/F curve is proportional to the SPL/F curve, although not perfectly, as the A0 response becomes weaker in vibration than as a sound radiator. SPL and the average vˆ2 is in general proportional for vibrating structures, in addition to a radiation efficiency term, like low frequency is less radiated than high for the same vibration velocity. 2. I do not know how click and pop relate to the v/F curve, but know Sam S talks about it along with transcients, which is related to the time history. Possibly a faster response? the wolf is subdued if the v/F goes down. Eg by increased damping or more mass. Lighter strings too. 3 on a HF you have the option to increase the pitch, I think that makes the response faster. For a violin I would guess a tight setup may help. A light but not floppy build. Maybe the bassbar is important? I should ask what your experience is on this as a pro maker and fine violin photographer. I think the preferred violins are as loud as possible, risking a wolf Balancing the B1- and B1+ will limit the wolf problem somewhat. I have never had volves on my regrad violins. Maybe not pro grade wood nor making, but can also be the result of a good B1 balance. They are usually about equal in height. Your reasoning, as if there is a given resouce, a given «account» in an instrument that to some extent can be moved around a bit, seems reasonable to me.
  6. Click and pop sounds like Sam Zs transient descriptors of violin sound and I hear his way of doing attacks and passages on the g string. However I do not know what it means, besides the observation. Maybe something about a firmness and ability to speak and follow in the fast and aggressive passages. The transcients. A bowed string tap the bridge evey time the Helmholz kink hits the bridge. It happens at the frequency of the played fundamental. The sound in the room consits of such decaying tapped responses. As the ear is presented to a log repetive series of similar responses it is believed that it does form an impression to the brain that embodies the characteristics of the violin sound. Much more than the experience we get from five, or just one tap, from an impact hammer measurement.
  7. I think much of the idea with the Stradivari, the secret if you like is belief more than anything else. Stradivari is not particularly interesting for me as I make Hardanger fiddles.
  8. The minimum bow force is larger at the resonances, and particlularly large at the wolf. For the playability the velocity over force plots merged with the string impedance, give an idea which notes will be difficult to play. It will be the highest peaks. The idian researcher Raman studied musical instruments early in his career. One of them was violins. He measured the minimum bow force for some instruments and noted that the minimum bow force to get the helmholz motion to go in the bowed string, coincidenced with the main resonances of the violin body.
  9. v/F is velocity over force, the admittance. It can be measured with an accelerometer or a laser vibrometer at the bridge side and tapped on the other side of the same side with an impact hammer with a force sensor in it. The v/F is what the string "see" at the bridge or the nut.
  10. To describe the instrument response fully, the bridge needs to be tapped at at least three or four strategic places to get the full movement. Impact hammer spectra usually show one of a merge of two: One sideways a the G-string side and another downwards in the middle (Joe Curtin). Violins in general do sound similar in any respect because the resolution to hear the difference between them is not very strict for listeners. You only need to be in the ballpark. And the spectra, along with the bridge admittance, can give you part of that information, along with playing them and comparing.
  11. The v/F is to a very limited degree adjustable. It is limited by the construction and to some extent the setup of the instrument. Strings can affect it, but always at a cost. A wolf is caused by a too strong v/F.
  12. Yes, the bridge adittance v/F at each string notch and paired with the string impedance. At the strongest resonses the bow need more force to get the Helmholz motion going. The minimum bow force is higher at the resonances and it has been shown at least for celloes that the admittance curve does predict notes that are difficult to play. Jim Woodhouse, George Stoppani and a fine british cello maker, Robin Atchison, conducted some experiments prior to the 2013 Stockholm Musical Acoustics Conference. Sort of a «Gluey» concept on a varnished cello.
  13. If you believe the Strad sonds better than everything else, it probably does.
  14. If you believe it sounds better with the ultrasound, it probably does.
  15. yes, but nobody can hear it, except for the bats, rats, cats, bunnies and sheep. The experiment cant have been done double blind
  16. I do not think ultrasound play a role in the listening experience for humans in general. Not for the bone conduction either, except for very strong levels. (We also can sense sound below 20 Hz if it is very strong). I also think it is a waste of storage and money to record sound for the bats. Even mp3 coding works for most humans cutting everything beyond 16 kHz, I think. The recorded ultrasound from the instruments referred to above seems reasonable. But weak, -40 dB in relation to the fundamental. If we did hear it, it would be masked by the lower stronger harmonics.
  17. The effect of damping tends to increase with frequency. Some pets do hear ultrasound and may react. I have never seen spectra beyond 20kHz from a violin, but some do actually record it up to, say, 100 kHz. The 2L recording company here in Norway record classic music also that high in frequency and in a 3D representation. The playback has been BlueRay discs. Ultrasound mic and analysis systems for e.g. bat studies let you record ultrasound and play it back in the audible range so you can spot them in situ. We actually have such equipment at work, Maybe it would be fun to try? I would guess that some ultrasound may appear from the bow string contact. The air is more absorbant to high frequency sounds, so the produced ultrasound may not carry so long. In scale tests of room acoustic models they use dry nitrogen or signal processing to deal with the higher losses in the higher frequencies.
  18. I think yopu are clamping the bridge too deep in the vice. At least that matters for a normal bridge. As low into the vice as possible and still having a rigid mount.
  19. I'm returning to the damping and a SDOF model for the bridge using Woodhouses damping data from his article on the bridge hill. You also see the formulas for damped SDOF mass free decay frequency, and the resonance when the bridge is forced. Both are a little lower than the undamped version. Woodhouses model also contain the effective bridge height, the width of the feet and a model for the top and back plates as well as a soundpost. All as a "cigar box model" I think. The bridge is also modeled as a torsional spring in his model, more correct than my simple mass, spring and dash-pot model. I am not sure if I have understood the damping in his graph correctly, he uses the damping factor. These values should relate to the highest and the lowest in his analysis and I have interpreted them as eta = 0,36 and 0,38 respectively, because the damping factor is equal to eta/2 My first impression is that the effect may be larger than we actually have in a violin. However, the amplfication also below 1kHz, although small, is interesting. The f0 is set to 2,2 kHz.
  20. In a JASA article from 2000 the Bernardel violin appear as a «good professional violin». Maybe it has been set up with a better bridge after the experiment with holding it for playing? Or maybe the damping test was done earlier?
  21. According to regression on normal violins version B is likely to work better than A. Lower arched backs are better, given that the results holds.
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