Andreas Preuss

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Everything posted by Andreas Preuss

  1. I think damping is only necessary on the top plate. For wolf notes I thought it has more to do with the thickness and arching of the top. The lower and the thinner the more likely you will have a wolf, or not?
  2. I didn’t go too much into cello acoustics so far. There is a chance that for low sounding instruments the bass bar must be under the bass side bridge foot. Thanks for the response.
  3. We often assume things without further testing. The answer I got from David burgess confirms my theory that the bass bar and the sound post are important sound factors but reversing them doesn’t change awfully lot, at least on a violin. But maybe this minimum change can be used in a advantageous way for what I call sound calibration process. With the new concept violin I am trying to find out how to calibrate single structural elements to each other to balance the sound in all aspects. I am working on the assumption that if the string forces can act most efficiently on the body I can
  4. I was thinking that the bridge is a sort of clamped on the sound post side. With the e strung we have a strong clamping. If we put the clamping on the g string side it is less and should allow the bridge an easier pivoting movement For the high registers I am (after reading David burgess explanation) not so sure any more that it needs to stand on the post. I have the suspicion that there needs a blocking mechanism under the bridge so that the neck forces can work efficiently and this is also the reason why neck angle and projection can change so much on the sound of an instrument.
  5. It takes definitely longer. For a cello top it needed over one year until it stayed under water without weights on it. Later I realized that in the case of spruce it is not necessary to get it 100 penetrated by the water to do the subsequent steaming process. Now I am actually looking more into pure heat treatment for spruce though I am not able to do your torrefication in a vacuum chamber.
  6. I would say none of the research papers I have read shows anything of the first 8 points in the list you show above. In the past I was mostly puzzled by the fact that no research on the varnish and ground would mention from where the sample came from in terms of spruce or maple. For the rest I am sure that Dr. Tai will explain in detail the last 4 points in the upcoming paper.
  7. The neck will drop a lot, because the back plate will bend in the region between upper block and top block. Therefore I'd adjust the fingerboard projection a good 5mm higher than needed for the previewed bridge. If you are nervous about the neck getting loose you can double pin the MDF plate at the top block (or use a metal screw), but I don't see any reason that this can happen unless it is really badly glued.
  8. If I think about it, your experiment seems to aim rather at speed of sound in the material. MDF must have a pretty high damping. Most wood treatments change this property for the better or worse.
  9. Just my opinion, but we are working with wood, aren't we? So any varnish which looks like a polished car has to me a sort of metal-work-taste. And just besides, factory work has always a flat varnish. I really get an adrenaline boost when I see a varnish which emphazises the wood structure underneath. (Not talking of antique finish here). I vividly remember the moment when I first saw a violin by @David Burgess as a young maker. I was literally blown away. On the top you could see every single grain of the wood and the back showed the waves of the flames on the surface absolutely nicely.
  10. I am not a scientist to verify or disprove your arguments. I only know that Dr. Tai is doing his research the best he can in the minefield of variables. I am sure that he prepared his samples to avoid any contamination’s from coatings etc. and compared them with wood of a similar age group. He asked me as well to send him samples of wood with my treatment to have a comparison to wood where the treatment procedure is known. The fact that he has to work with only very few samples is an obstacle all scientists face in this situation. (Try to convince the owner of a now multimillion dollar ob
  11. Just for clarification. Boiling and steaming are two different procedures. For boiling the wood needs to be immersed in boiling water. I tried it too on small wood samples but abandoned the idea after the first test. I am doing steaming which is exposing wet wood to hot steam in a specially made steam chamber. Once I was able to monitor the inside temperatures which was between something like 90 and 95 Celsius. When water would run out from the water tank the temperature would drop below 90 Celsius. My first test was with green wood without soaking on a special order to a
  12. Just for clarification on this experiment: You are replacing a back plate made of normal wood with a back plate made of MDF, right? Arching is supposedly approximately the same? What I have seen on my super light violin project is that changing back plates does not change awfully lot in terms of sound. What is more interesting is how playability and and perception of sound under the ear does change. Softer back plates make the sound more diffuse. At the same time lower resonances get stronger. All this looks to me that a ‘good sound’ (whatever a maker defines as such) is ba
  13. Here is something I need to tell you in this context 8 years ago I made a violin with treated wood, first soaking and then steaming. I finished it, set it up and when I played it the first time it didn't sound. (the same day I was VERY BUSY to fumble around with the sound post and bridge using swear words in all the languages I know)) After one week the sound transformed slightly, and after one month I realized that the sound in fact evolves in a way that overtones develop to build up little by little. And after one year it sounded not only very good but had a rich quality which became si
  14. You detected Aluminium in rather high quantities, ok, but I have to ask why do you deduct from there that it came from alum? There are other metal salts which come from aluminium. To find out for which reason it was used it is always very helpful to find old recipes for wood treatment. So I would rather accept that GDG simply used it for the same reason as Romans. The effect on sound, if there was any, was not intended.
  15. Could he have added something he didn't even know that it exists? Zirconium was first discovered as an an element in 1789. The mineral jargoon contains Zirconium and was apparently known since biblic times, but this is again a pretty far stretch. I see all those 'funky' elements found by analysis more or less as contaminants in another product. One thing is sure. Alchemists could do a lot of stuff, but they couldn't test the purity of their products. Or, depending on the dosis maybe the tree soaked it up from the soil it was standing.
  16. I was digging into this when I had the idea to treat wood with alumn, too. It seems that the Oseberg relicts from the Viking boat were dipped in a boiling alumn solution in an attempt to stop decay. This was about 100 years ago. In any case the wood was not fresh from the tree. If I remember correctly the chemical transformation to Sulphuric acid is interpreted by the treatment of a hot and oversaturated alumn solution. In those terms I am not sure that a light and cold solution of Alumn will have the same effect on fresh wood. For the concentration or lets say homeopathic dosis it certa
  17. It seems that still 30 years ago scientists were driven by the belief that there is one secret which could be discovered, nowadays it goes rather the opposite way and scientists try to proove that there is no secret at all. 1. OK 2. I don't like the word 'complex'. The process was as practical as it needed to be and follows a down-to-earth logic of a craftsman in the 17th century. 3. To quote in this context Sacconi is in my view wrong. Before Sacconi wrote his book everybody was looking for one varnish secret. Sacconi was the first to say 'Hey folks, if you think there is one s
  18. Hemicellulouse degradation is certainly not the universal recipe to 'specialness'. However, there are strong hints that the wood was treated from the beginning. Roger Hargrave interprets it as a process with rabbit goo and pee, I myself got into a sort of soaking and steaming the wood for maybe the same result. Starting from the beginning with a sort of different material makes certainly a difference in everything that follows. From my own experience I can say that using steam treated maple makes a distinctive difference in sound timbre especially on the lower strings. This is based on some 2
  19. Here we are returning to a previous discussion. I really can't help to see stress or static load as one of the factors to bring out the entire sound spectrum on some instruments. I base this on the experience of one violin I made which didn't sound at all at the beginning (not the super light violin) and just keeping it under string tension for at least one year it started little by little to 'shine'. I literally didn't change anything else except moving the soundpost around. If you find another explanation than static load which a kind of 'stretched in the structure' I'll go for it. To me
  20. Then I would suggest rather than atomizing wood structures it would be time to elaborate on a scientific background concepts for designing the sound in a workshop using methods of the past as a basis. Science has a bit the frenzy to use last available technology to find something new, literally storming to the next 'media-spectacular' result. In the meantime testing what has been found so far gets largely neglected. We may ask ourselves too, why we need to use I-don't-know-what-sort-of sophisticated technology to find out what makers in Cremona did with no scientific knowledge just with their
  21. I know a violinist who said to me repeatedly that my instruments lack 'resistance'. For a long time I couldn't figure out what he meant by that. I knew only that the G string of his instrument was unplayable for my violin playing level. Now little by little I learned to understand that there is 'something' which very skilled players sense in their bowarm through the contact of bow hair and strings. It has nothing to do with sound quality or overtones. And this 'contact impression' gives them a very precise idea how they can drive the instrument. In those terms, if a professional
  22. Not foolish at all. to me a great part of violin research reveals things which are somehow interesting but don't go to the point. The thing I would like to know most is what exactly causes which overtones and sound projection. Right now I have only one hypothesis in mind.
  23. From experience, I have to disagree on this. With an intense and reflective ground only a very small amount of pigments is needed to make a pretty intense color varnish. Substractive color blending plays a role too, because cocineal pigments as such are too blueish. Tested on a white ground it looks too purple.
  24. IMO, definitely not. On a side note I was thinking why the transformation of the original baroque setup to modern setup was in most cases successful, and in a good percentage of his output absolutely exceptional for the sound.