Andreas Preuss

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Posts posted by Andreas Preuss

  1. 5 hours ago, David Beard said:

    Interesting experiment.  I would have expected the string switch to manifest more differences.

    The thing is, more than often our premade assumptions prevent us to explore new variables of the existing concept.

    I have to say clearly that making alterations and expecting a ‘positive’ result just by doing it, usually doesn’t work. Each alteration needs the sound re-calibration for the entire structure mostly to get rid of the negative side effects.

     

  2. @Don Noon

    Finally had some time to listen to the YouTube with earphones. 

    It has an interesting smokelike nasalness to me. Its just the right dosis and evenly distributed on all strings giving your instrument a distincive sound. It seems to react pretty well to the bow too. Hard to judge from a video, but never got the impression that the violinist had to fight against the instrument. I like the timbre of E and A string the best.

    If I had made this violin I would put the following improvements on my list

    • Work on getting more depth on the lower strings. One could say that the G string is a bit narrow
    • could have more varieties in tone color. (Sorry, I just had to listen to the same piece played by Aaron Rosand presumably on his del Gesu.)

    But that's certainly a matter of personal preferences.

    I'd say 'compliments, Don!' considering from where you started. Maybe not altogether the shortcut to sound perfection in an instant, but I guess your scientific background at least made trial and error based experiences much quicker than for people fishing red herrings once in a while. :D

  3. 7 minutes ago, Don Noon said:

    I'm pretty sure it would work... but you might not like the side effects.  A0 would be weaker, and the wolf on the A string would likely get a bit worse.  And all the other unpredictable tonal effects and perhaps feel.

     

    Hmmm sounds almost as if we were talking about Chemo therapy. You get rid of the disease but the side effects will kill you anyway. :wacko:

    I only noticed that on my new concept violin there are some abnormalities for the signature modes, despite it sounds pretty good. So now I am looking into some well examined changes to get the result I want. At least, reversing bass bar and sound post is always reversible to the original.

  4. 8 hours ago, Don Noon said:

    It might surprise you how much the soundpost (and back) move, even at some lower frequencies.  

    Yes, this can be seen on those holographic pictures. 

     

    8 hours ago, Don Noon said:

    Reversed post and bar should make the wolf less of an issue on the high G string.

    If this would work, it would be a quite new and elegant approach in killing the wolf. This is something which extremely matters to players.

  5. 2 hours ago, Marty Kasprzyk said:

    I believe a high amount of damping isn't necessarily bad--it should reduce note starting and ending transients which would make fast passages less blurred and it should reduce wolf notes.  

    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?

  6. On 5/3/2021 at 2:00 AM, gtd said:

    I have a cello in my rental fleet that came stock with the post and bb swapped around. top end was okay but bottom end had nothing to it. Switched out the bottom two strings and it improved enough to call good.

    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.

  7. On 5/3/2021 at 5:56 AM, Greg Sigworth said:

    Which gives more structural support to the downward forces of the two bridge feet, the bass bar or the sound post? Is there more support needed under the "e" string or under the "g" string? Maybe there is a structural reason for the current setup.

    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 gain a maximum sound output. This is certainly not the end of the story because sound response and overtone range also play a role. 

  8. On 5/2/2021 at 12:37 PM, Don Noon said:

    I would expect the opposite.

    Due to the bowing angles, the lower strings have a greater vibration component normal to the bass bar, and the E string would have its vibration more normal to the soundpost.  Reversing these i would expect to have a thinner sound to the low strings and a fatter, less brilliant sound to the E string... but to what extent is unclear.  It may be minimal.  Or there could be other frequency sensitivities that get switched.

    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.

  9. 18 minutes ago, Don Noon said:

    [...] dried spruce is usually resistant to soaking, and I have needed to use cycles of pressure and vacuum to get liquid to penetrate.  

    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.

     

     

  10. 1 minute ago, GeorgeH said:

    So this is the point - one cannot assume or “be sure” of anything because we don’t know and Dr. Tai hasn’t said. This is why discussion of methods and materials is critical information in any presentation of scientific data. What we don’t know includes:

    • When were the samples were obtained?
    • How were they were obtained?
    • What specific violins did they come from?
    • What specific locations on the violins did they come from?
    • Where did the control samples come from?
    • How were the samples stored?
    • How long were the samples stored?
    • What containers were the samples stored in?
    • How were the samples prepared for testing?
    • How were the tests performed?
    • How many tests were performed on each sample?
    • What is the experimental error of the tests on these specific kinds of sample, e.g. accuracy and precision?

    And so forth.

    Without any of this information, it is impossible to judge the veracity and usefulness of the data or to draw any conclusions from it.

    Furthermore, even if the data turns out to be real and scientifically defensible, it is simply impossible to say if Stradivari or Guarneri had anything to do with it. There are other potential and equally likely reasons to explain the results that have nothing to do with either one.

    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.

  11. 3 minutes ago, Don Noon said:

    Hopefully this thing will be playable, and hopefully the weakness of the MDF won't allow the neck to snap out or droop too much.

    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.

  12. 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. So this didn't come from the varnish alone but a very delicate wood finish as well.

    Later I saw the work of Christoph Gotting. I knew that he was (and presumably still is) a complete varnish nerd. He showed at a violin makers convention in Germany one of his latest instruments. It was a copy of a Venetian instrument, but varnished like new without antique finish. His varnish had a sort of orange peel surface and really looked like fresh from the workshop of a Venetian maker 300 years ago.

    Then, in comparison, if I look on the perfectly flat varnish of a  Kantuscher, who certainly is one of the greatest german masters in the 20th century, it gives me a rather the impression of Japanese lacquer or a computerized design. It has to me a cold feel because this kind of varnish ignores the wood underneath. (But I have to admit that it matches really perfectly his overall calculated approach.)

     

  13. 14 hours ago, GeorgeH said:

    Of course, assuming that the presence of Al is real, Dr. Tai has no proof whatsoever that it was actually put there by del Gesù himself and not by the his wood vendor or even somebody later, but lack of proof never stops him from treating his far-fetched speculations as if they are facts.

    The only real "fact" that Dr. Tai has possibly shared is that he found some Al in two (2) tiny "flakes" allegedly from del Gesù instruments.

     

    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 object to chunk off one cube millimeter of his/her precious possession....)  If we look on all the investigations in this field, I cannot remember any which based the result on many samples. Usually scientists open a very mall window to find clues. Sometimes a fraction of varnish or wood small as one square millimeter serves as basis for a research project. So did Woodhouse Et al., Nagyvary, Brandmaier Et al., Echard et al. Dr. Tai’s research is no exception.

    Reviewing the history on the search for the ‘Cremonese secret’ we can safely say that scientists looked into basically all thinkable variables so far, except wood treatment. Alone the fact that the wood of those instruments shows abnormal proportions of certain elements should be good enough to look a bit deeper into it. Though I am not subscribing to the idea that GDG desperately soaked his wood in an attempt to compete with Strad, there must have been somewhere some reason for which Aluminium got into the wood structure and apparently more than is found in naturally aged wood. I find however more interesting that Chlorine in rather high amounts could be identified in Strads wood. Natrium chloride is the only possible source (otherwise there is only one rare volcanic ash mineral containing Chlorine which seemed to have been accessible to makers in Italy in the 18th century) and is neither used as an ingredient in the ground nor in the varnish. If all the wood from Bosnia was transported by floating it in the Adriatic, Guarneris wood should show the same analytical amounts. This gives some strong indications that something has been done. Who and when poses big question marks and Dr. Tai is saying in this respect that there is still a long way to go.
     

    My own take as a maker on such findings is always to figure out if those scientific hints make sense when making instruments. I find it interesting enough that Strad samples and Guarneri workshop samples seem to be distinguishable different. 
     
    In a scientific sense it would maybe good if a different research group would try to analyze the wood  with a different approach. I am sure Dr. Tai wouldn’t oppose.

     

  14. 12 hours ago, Bruce Tai said:

    Which wood did you steam? 

    We have learned that boiling spruce can promote cellulose rearrangement but boiling maple cannot. 

    There are fundamental differences between softwood and hardwood. A topic that is underexplored. We are just beginning to explore. 

     

    12 hours ago, Don Noon said:

    The time or two I boiled spruce, the rectangular cell structure collapsed.  I never tried boiling maple, but the smaller, more round cell strucure I think could be more stable.

    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 wood dealer.

    Later I tried variants of soaking the wood, with different results. 

  15. 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 based on how the top is designed as a membrane. All the rest is a kind of modifying those properties. When making the back a kind of weaker the whole setting of the string angle needs to be readjusted (re calibrated) to make it function to its best again. In that case I would most likely lower the string angle.

    i am not too much experienced with reading sound graphs, but there my prediction is that you might end up with a graph of less sharp peaks in the  higher registers. 

    In term of wood treatment I am not quite sure how valid this experiment is, because MDF as a material lacks one important factor because stiffness in vertical and horizontal direction is the same. Natural wood is always different in both directions. Wood treatment changes the stiffness in both directions, but never to the degree that they become equal. My experiments with steaming wood (not boiling in water) made maple measurably lighter and tap tones of the uncut planks got a bit higher presumably due to weight loss. On spruce this method didn’t show a significant change.
     

    I was always wondering how internal stress in natural wood affects the sound. I am inclined to think that treatments like ponding wood in water relieve stress. There was one scientific paper which compared violins and the violin made with ponded wood showed different all over sound characteristics. (I would need to look it up again, I think it was a paper where Terry Borman participated as a maker) 

    Usually my predictions are just the opposite what you come up with. :D

  16. On 5/1/2021 at 9:47 PM, GeorgeH said:

    I will also add that the folklore about instruments "waking up" that Tai posted here is not about an instrument sounding better after 5 or 50 minutes of playing. It is about "Top players often say that it can take them as long as a year to coax the kinds of sound they want out of instrument." See that? "As long as a year." (I also don't really hear "top players" saying this "often.")

    So, in typical pseudoscientific gobbledegook, Tai says, "that stress-induced deformations will redistribute water molecules in the wood. 'Although precise measurements are difficult, it is not far-fetched to attribute the awakening of old instruments to these factors'"

    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 since the measure for all my violins.

    Unfortunately I can't provide any verifiable data for this. And I am definitely not scientifically trained enough to provide any explanation better than 'stretch-in effect'. I know only that the violin needed one year to develop its true sound. 

    The fact that some top  players need one year to adjust to a new instrument is a completely different story. 

  17. 20 hours ago, Bruce Tai said:

    Aluminum ion in alum will crosslink wood fibers via coordination bonds.

    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. 

     

  18. 4 minutes ago, Bruce Tai said:

    I don't know why he even added some Zr4+ into his wood.

    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.

  19. 18 hours ago, Anders Buen said:

    I can tell you what alum has done to the viking grave wooden artefacts and objects at the Vikingship museum here in Oslo after being treated with it in an early attempt at conserving the 900 year old woood. The interoir has degraded into dust and the objects are held together by the outer linnen oil based treatment. The alum and wood reacted to create sulphuric acid. The ships are not alum treated, however. So they are in better condition.

    If we are talking about the same thing there would probaly not have been any violins left if they were alum treated. There are lots of literature on it. «Saving Oseberg» may be a good searching phrase.

    having said this. I am very surporised that any serious researcher can believe that 1000ppm of something (1000ppm 1000 particles or molecules in a million) is going to make much of a difference to the acoustical properties of something like a violin. 

    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 certainly does not sound reasonable that it makes a change, but I would not be too quick to dismiss it unless the opposite is proven.

     

  20. On 5/3/2021 at 3:21 AM, Bruce Tai said:

    Many of you may be wondering what modern science can really do for violin making? 

    Scientific research is not about making advanced products or giving instructions on how to make advanced products. When is the last time you bought an advanced product by an academic lab. 

    The most powerful thing about science is providing conceptual frameworks.

    Allow me to explain. 

    The concept of LASER (light amplification by stimulated emission radiation) came from Einstein's prediction of stimulated emission in 1917. The first functional laser was only built in 1960. There is a very long way from concept to reality. However, there is no denying that new concepts can guide us to new achievements. Columbus had a concept of the orient, and the concept the earth being round. So he sailed west thinking that he would reach India.  

    So what concepts have emerged from the scientific examination of Stradivarius violins? There are plenty. 

    1. There is no secret ingredient in the varnish, nothing beyond the normal stuff that painters and varnishers used, all sold at the apothecary. We are finally sure that it is an oil-resin medium. So no need to worry about mysterious animal bloods or rare plant juices. 

    2. The varnishing procedures of Stradivarius was complex, not simple. First smoothing the wood, then sealing the wood, applying the ground layer, and finally color varnish. There is no shortcut for reproducing the visual appearance of Stradivari's varnish.  

    3. The varnish is not the magic bullet for favorable acoustics. So Hill, Vuillaume, and Sacconi were wrong. Stradivari's varnish may look special due to his skills and tricks, but it is not fundamentally different from what some copyists have tried.  

    4. The wood used by Amati, Stradivari, and Guarneri were treated with diverse chemical recipes. Whatever the intentions or the final effects of such treatments, old masters were clearly conducting chemical experiments. My next paper will show that spruce and maple were both treated. Cremonese simply did not use natural wood (air-dried) for violin plates. 

    For those who wish to pursue the recreation of Stradivarius violins, the paths are now much better defined compared to 50 years ago. No need to try the crazy stuff or listen to crazy theories. Scientific data can tell you that Stradivari did not spray the alcohol solution of dragon's blood over nitric acid-treated wood.  Scientific data can provide a conceptual boundary of what can be tried, but that's very different from actual technical instructions.  

    Psychoacoustics is a very immature field. Black boxes everywhere. After I published the first formant study of Stradivarius recordings in 2012 in Savart Journal (inspired by Nagyvary's unpublished works), several other groups have started to investigate the analogies between violin sounds and human voices in a quantitative way. I think this may be a useful concept for understanding violin psychoacoustics. But such knowledge is just the tip of the iceberg. There has to be be fundamental breakthroughs in measuring real-time brain activities before we can unlock the many mysteries of psychoacoustics. Regardless of whether Strads are the best, we know that there are super nice violins and bad violins. But we don't understand the acoustics signatures that set them apart. 

    Currently there is no good way to link these four different things using available science:

    Material properties => Body vibrations => Acoustics output => Auditory perception  

    Hence, don't expect modern science to provide instructions on how to build superlative violins. Only great makers will be able to make great violins. I don't know how that works. 

       

    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. :rolleyes:

    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 secret, you are trying to land on the wrong planet.' therefore he consciously chose the title 'I Segreti (in english Secrets)di Stardivari' So for him the mystery consisted of many secrets which were interlinked to each other. To me he was also the first who tried to boil it down to a concept of making. (Hope this is NOT spinning off into a discussion of the 'mistakes' in the book)

    4. I'd say more precisely 'alchemical experiments'. But like the varnish we can't rule out the possibility that those 'ingredients' came from a third party (i.e. the wood dealers) To go as far as viewing GDG in his workshop and soaking wood in alumn solution to compete with Strad is stretching the imagination a bit too far.

    I don't see any reason why science should play the role of standing back from engineering products more actively. Especially in the field of chemistry, scientific research could provide manufacturers with tested procedures to get good results. 

     

  21. On ‎5‎/‎1‎/‎2021 at 5:24 PM, martin swan said:

    Therefore, if we were to attribute some "specialness" to classical Cremonese instruments that was connected with hermicellulose degradation, it would have to be in combination with something else, for example the unique use of a preservative or unique properties in the wood at the time of making. I think this is where Don is headed and I like his unfussy experimental approach.

    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 20 instruments I have made with steamed wood so far.

  22. 8 minutes ago, Don Noon said:

    I don't think that the static loads contribute much to the sound. 

    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 it is still a sort of mystery.