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Torbjörn Zethelius

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Posts posted by Torbjörn Zethelius

  1. 1 minute ago, David Burgess said:

    Perhaps, presuming that fiddlemakers were anything close to well-versed in the engineering accomplishments of that era.

    We do know that Stradivari's step children in his second marriage were the grandchildren of the architect Alessandro Capra. I think I got that right. ;)

  2. 16 hours ago, David Burgess said:

    I doubt that anyone really knows what theories the 17th and 18th century Cremonese makers had it their heads. Some examples turned out spectacularly, sonically, while others did not.

    At least we do know which theories were in swing. True or false; we can make some deductions about their theories.

  3. 21 hours ago, DonLeister said:

    I was hoping to catch the reflections in the areas you mentioned. This is the 1711 Strad at the Metropolitan. I have several more short clips if you like.



    That's what I called the 'bread loaf' in my first article from 2006. I guess it's called the barrel arch nowadays.

  4. 10 minutes ago, jezzupe said:

    Wax? hmm, you are a renegade aren't you :lol: I like a light coating of something often times, Joe Robson suggests a light coating of his #2 {not you know #2 :lol:} but his product #2 . I like the thought of retarding vapor absorption some,but not too much, I do think one can go over board with an interior shell that is too sealed, not a big fan of double sided sealing off of the wood.

    :) It's extremely thin. Almost non existent.

  5. 52 minutes ago, David Burgess said:

    Doesn't most of the sound of a violin (though not all) radiate from the outside surfaces?

    That's not how I think of it, though most makers would probably agree with you. The way I think about it, the sound is created inside and outside of the violin body simultaneously, like an explosion. Or a series of explosions. Likewise, the sound that reaches the ears of the listener is formed at some distance from the player. 

    51 minutes ago, Andreas Preuss said:

    Hmm. If we take a concert hall as an analogy, the sound source is separated from the reflector (the walls). In a violin the source and the reflector are the same. How does this work then? 

    Your guess is as good as mine.

    50 minutes ago, Andreas Preuss said:

    Was it in the foreword by John Dipper? Maybe I am wrong.


    Yes, but I don't remember him, Andrew, stating it to be theoretical only.

  6. Just now, Andreas Preuss said:

    But in the end, segreti di butegha was most likely not written by a maker. It is the interpretation of someone who tried to find out what principles Cremonse violin makers followed.

    Where did you get that information from? I'm not even sure it's about Cremonese instruments.

  7. 5 minutes ago, Andreas Preuss said:

    Sure. My point was, that if the ideal reflection is the main factor for 'good sound' distortions would destroy it over time. And if your arching theory is right, basically all barrel arch shaped Strads are deformed (thats probably 99 percent) and some of them still work extremely well.

    At least, If I would weight which argument works better

    1. sound prodction comes from inner reflections created by the inner arch shape

    2. sound production is a result of the arch stability. 

    I am definitely for the second argument. And actually, thinking about stability it makes a lot of sense to carve the arching from the inside first.


    I have some problems to think of 'sound beams' inside the instrument. This would in theory mean that you have a source of minimal dimension which emits the sound. As a matter of fact the entire surface is vibrating. Taking each spot as a sound emitter would make an uncalculable number of sound beams interfering with each other. That looks to me like an (almost) chaotic system. 

    They don't rule out each other, do they? I think we seem to agree mostly.

    The term 'sound beams' should be understood in a broad sense. I don't necessarily subscribe to the notion and yet I think it was the old way of thinking about it. That's how I understand the Segreti di buttegha describes it.

  8. On 4/4/2020 at 10:55 PM, Davide Sora said:

    An interesting video with some beautiful images from the skies of the deserted city. A better use of drones, rather than using them to search for those who break the quarantine....:D


    Thanks for sharing, Davide! It's a strange time. 

    The echo didn't seem quite fit for the video, but maybe the ceiling in the tower did have some effect on the sound, who knows?




  9. 46 minutes ago, jezzupe said:

    Torbjörn, While you may disagree with the "it does zero" statement, are you disagreeing that coatings effect the violin plates properties? and also disagreeing that "bracing" such as on guitars which is an internal "topography/texture" does not effect stiffness and elasticity? 

    How can I disagree with that? I haven't tried everything that can be done to the surface of the wood. My philosophy is that less is better. Of guitars I have no opinion.

    31 minutes ago, Davide Sora said:

    Yes, he makes a specific reference to the book "Segreti de Buttegha" and dedicates a chapter to it if I remember correctly.

    I also believe that Peluzzi's theory fits perfectly with the inside first method, but it doesn't make it more appealing to me:)

    I don't have any notes from Stradivari, but I have some notes from Guarneri that my great-grandparents had found in the cellar, do you believe it? After all, they were from Cremona and this is more likely than Peluzzi's supposed Stradivarian notes.:rolleyes:

    To each their own. 

    I'd love to see your notes from Guarneri if you would mind showing them to me. That seems really exciting. :) For sure Stradivari had notes, but I suspect that they were destroyed after his demise.

  10. On 4/6/2020 at 1:14 AM, Fade said:

    Hi everyone! I would like to talk about my approach to the liutherie that is different from modern liuthers. The main differences are that modern maker's are trying to copy things like thicknesses and external arching but for me it has no sense because thicknesses are specific for every piece of wood and the external surface(arching) is a consequence of the project of the inner area (where the reflections of the vibrations take place) that works like a concave mirror for light waves. This system is shown on a book Peluzzi "Tecnica costruttiva degli antichi liutai italiani" he also reports notes from Stradivari that he checked personally(maybe he is lieing ,i don't know it) ,for him all old liuthers had a different concept of violin making than modern liutherie. He explains how to find the position for soundpost and bridge, he explains the stradivari system,but some italian makers say they don't agree with him! I personally found his system very interesting and I know you cannot read the book cause it s in italian but if you want I can try to explain that with photos or video.
    If there is any maker here that would like to talk about it would be great.

    Thank you for the opportunity of expression.

    When I wrote my article about the inside first approach in 2006, I wasn't aware of Euro Peluzzi's book. I think his idea came from Librum segreti di buttegha, which also speaks of the internal reflections of the plates. It was the philosophy of the old makers IMO. Interesting that Peluzzi claims he reports notes from Stradivari that he checked personally. Perhaps they were mixed together with the text in the Librum segreti? As far as I know, there's hardly any notes left from Stradivari besides a few letters and his will.

    A scientist in those days was called Philosopher, i.e. they mixed scientific experimentation with speculation about the nature of things. I think this is an honest and true description; science can't be perfect because it is employed by humans who are inherently imperfect.

    20 hours ago, Andreas Preuss said:

    I think I have seen the book long time ago. The author claims a sort of sound reflection which bundles the sound towards the f -holes (that's what I understood from the graphs and my rudimentary knowledge of Italian) However this can not be verified by any means. 

    From restoration of instruments we know positively that the archings deform and this would undoubtedly destroy the focus with only minimal arch alterations. 

    Secondly from an historic point of view such thoughts seem to me completely anachronistic. I doubt that they knew that sound can be viewed like a lightbeam which would reflect on a surface like a mirror. If we read the manuscript written by Antonio Marchi in 1786 his 'acoustic' explanations are full of strange descriptions which definitely don't match our modern understanding. 

    Yes, archings deform over time. That doesn't rule out that makers can make the internal surfaces similar to each other to reflect the sound beams. I'm not sure that the old makers were aware that their instruments would be taken care of and played for over 300 years. Some claim that modern instruments can be as good if not better than the old ones, so the internal reflections could well be at work here.

    18 hours ago, Davide Sora said:

    This is the book and a page for example of the unnecessarily complicated theory. Furthermore, from the detail of the cover it can be seen that he was using the external form, not very consistent with the method of old masters. Also, if this theory would be applicable, I would expect to see a mirror finish inside the ancient violins to improve reflections, which is absolutely not the case. So I think it is a waste of time to do all these calculations, at best the violin will sound like all the other violins if you build it well, but the theory of reflections has nothing to do with the results you can get.


    I agree that it seems overcomplicated. But I don't agree that the theory of reflections is pointless.

    16 hours ago, MANFIO said:

    I have this book, the theory is just.... too complicated.  The man in the front cover is Euro's father, if I am not wrong.

    If I remember correctly, Bruce Carlson showed me a violin by Euro's father. 

    13 hours ago, Davide Sora said:

    There is no doubt that there may be a relationship with internal reflections, but proving it is stuff for modern scientists who like to have fun and who have a lot of free time. To say that this was the "technique of the ancient Italian luthiers" is highly improbable and at least pretentious, do you see Guarneri del Gesù doing all these calculations?

    I don't see him doing the calculations, but definitely the inside archings before the outside. I also see him/they doing experiments as we do today.

    8 hours ago, jezzupe said:

    Interior surface "texture" has about 0 to do with a good sound. I have experimented with both coatings as well as interior lattice work, both of which effect the stiffness/ elasticity of the plate in general, but as a whole,inside the "tiny little room" inside the violin, surface texture,be it smooth,rough or interrupted, as long as those interruptions are on the plates,and not partitioning or baffling the cavity, it does not much. what happens inside the cavity means nothing other than it is the "center" of the shock wave, we only care about what happens after it gets outside of the "machine". I will not say that "glass like" coating and preparations and or lattice bracing  will not effect the sound, but it is how it effects the mechanical properties of the wood and they're undulations during dynamic mode states, not about how sound waves travel inside the "tiny little room" .

    I pretty much disagree with all of that.

  11. 20 hours ago, Kevin Kelly said:



    Kevin is busy with the kids and work... :)    I will take you up on this one, but then I think I will go back to work for a while.






    Quattro Cerchi Recipe:

    Upper to Lower, 4/5

    C = Lower

    Waist = 4/5 Upper

    turn 2 lower = 2/3 L

    turn 2 upper = 3/4 U

    extension = L/3


    1) Draw a horizontal line for the diameter of the Lower Bout.

    2) Draw Lower circle, add second turns and make a center line

    3) Draw horizontal lines for the center of the c bout parallel to the center line, at a distance of W+C

    4) establish the center of the extension, 1/3 of the radius of the Lower bout

    5) Draw an arc w/radius  L + ext + C from the center of the extension in the lower bout (opposite side from the c bout)

    6) The intersection of the circle (step5) and the lines (step 3) is the center of the c bout

    7) draw the c bout arcs

    8) draw circles from the center of the c bouts w/radius  C+U. The intersection of these arcs is the center of the Upper bout

    9) draw the upper bout circle and a horizontal line through the center

    10) draw the second turns of the upper bout 3/4 radius of the upper bout

    11) draw the end blocks. In this drawing the lower block is from the top of the lower bout circle and the upper block is from the narrowest point (which is a mistake - it should be from the bottom of the upper bout circle - it was modified from a different design and I missed it)

    the stretch between the c bout and lower bout circles is up to the maker to deal with however they see fit.

    That's it.




    Kevin, your system is simple and neat but unfortunately it doesn't fit the outline of the guitar. 

  12. 4 hours ago, francoisdenis said:

    If somebody can get a better result using another way  I will be obviously very interested

    Hi François, here's my attempt at analysis. A quick glance it seems pretty close. The bridge is at 1/5 the body length, and it's all geometry.


  13. 12 hours ago, francoisdenis said:

    Dear Kevin, I go back to your Strad guitar shape solution

    I did the drawing following your measurement 

    The drawing on the right side is how the guitar is asymmetrical and on the left  in red is how your proposition really match

    2123795402_Capturedecran2019-09-30a11_42_04.thumb.png.6135974b4aba67c246af927cbe8a7cc0.png  1649138751_Capturedecran2019-09-30a11_46_42.thumb.png.d2e1d1226f0e2ffcb8cdb75ad3c9df92.png

    In regard with the asymmetry we can  consider that the measurements

    of the radii tangency to the UB  and LB are 1/3 of the width at this place  

    And  ratio UB/LB= 4/5   and  MB/UB = 4/5 could be OK .

    But it remains some other pbs and I would like to know how you solve them

    -How do you find the position of the maximum width of the upper part ?

    -How do you find the position of the minimum width of the middle part ?

    - There is two  straight lines to connect the upper and the lower bout  they are missing at your solution






    I want to see a division between Measurement and Curves. Two violins can have the same dimensions but look totally different from each other due to different curves. When we draw a violin from scratch we must first establish the dimensions and then build the curves around these dimensions. The curves and the dimensions is like the flesh on a skeleton. It seems to me that Kevin is constructing both at the same time, and that's problematic to me. David is on the right path IMO in that he establishes the dimensions first, which is the foundation for the whole structure. 


  14. 2 hours ago, Three13 said:

    What were the actual local Cremonese units of measurement between 1550 and the adoption of the metric system in the early 1800s? Not merely the names (I imagine they are some version of foot, inch and point), but the length of each unit?

    I ask because I've done substantial research on 18th century coins that required an understanding of the weights being used at the time - switching from grams to grains, pennyweights, etc., and measuring things in the way that the people making the objects did, ended up being essential to understanding what they were up to.


    The Cremonese architect Alessandro Capra published (in 1672) in at least a couple of the books that he wrote, the Cremonese Oncia (inch) which I've measured (as accurately as I could) being equal to ≈ 39.088 mm. One oncia = 12 ponti. 

    That gives: 9 Cremonese oncie = 351.8 mm. Add 1 ponto and we have 355.05 mm. Looks familiar anyone?

  15. 7 hours ago, Marty Kasprzyk said:

    Our tradition is to copy earlier successful violins.  I suspect Strad also followed this tradition but he occasionally moved his patterns around a little to break the boredom.

    You forget that the modern trend of copying stems from the French makers Lupot, Pique and Aldric in the late 18th century. They were forerunners of modern violin making. The Italians very rarely copied. 

  16. On 8/31/2019 at 5:33 PM, David Beard said:

    I found your statement interesting.  But when I looked at the G mold for a first check of the idea, I don't see relation between the string length and the distance between  blocks.  Not even close?

    What am I missing.  Also, the only intact Cremona necks (and therefore string lengths) that we can look at seem to imply lengths very similar to modern.  Differing just by a few mm if at all, so as to be by proportion instead of a fixed standard measure.

    Still not see it?


    My statement relates rather to the Amati tradition, which was the main thought up to the end of the 18th century. Stradivari was very experimental and he came up with many new ideas during his life. So I'd like to think of him as working within the tradition, but at the same time using it as a theme to extend upon.

    Take the G mould for example. The relation between the C-bout and the blocks is Pi. (I just measured it to 3,1434 close enough) Given in Strad's time (before calculators, that is) it is the same as if you take a piece of string and coil it to a circle; the C bout width equals the diameter of that circle. 

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