the function of arching shape

[violins88]

In the paper, quite long, the rib height is 28.5 mm. And I think it’s a viola. Is that typical rib height? Link https://maestronet.com/forum/applications/core/interface/file/attachment.php?id=161163&key=92ccbded99f12fe4b98793fda0f9f344

This paper appears to have a formal looking coat — The first pages look very formal, but it then appears to be very amateurish and informal, with frequent references to the “expert” Mr Reguz. 
 

Something’s rotten in Denmark.

 

 

[David Burgess]

10 minutes ago, Violadamore said:

Except for Sawzall bridge cutting, of course.      

Strangely enough, some people expressed outrage over that video, believing that it was serious, when I thought I had clearly presented it as satire.

Ya just never know!

[Dr. Mark]

1 hour ago, reguz said:

Dr. Mark I do not need the support of any person. I do what I do and show the results.

I'd say you've accomplished the latter.  Given that, what's your purpose in being here?

[reguz]

2 hours ago, David Burgess said:

But you have, in prior threads!

And people have responded, in super-specific detail, to most of your other claims as well, in prior threads.

So the mystery is why you keep trying to run this stuff up the flagpole again and again, apparently failing to understand that repetition is not proof.

David. I do not claim anything I just show what my research has shown me. Is there any wrong in that?

[Dr. Mark]

Per the dissertation - it's not bad.  Abacus holds some promise, but the discrepancy in the plate modes approaching mode 5 indicate some subtle effects that may be difficult to remediate.  The rubber band supports concern me a bit, and I'd like to see results with a different configuration for comparison.  On page 76 we find something of interest:  "In both Figure 6.11 and Figure 6.12 the deformations are presented in reference to the sound post, meaning the sound post is considered stationary while the violin deforms around it."  My reading of this is that measurements are taken with respect to the sound post as a convenience - there needs to be a reference point somewhere - w/o any other implications.

Figures 7.5 and 7.6 may be interesting references in the discussion about deformation and reconstruction of original classical arching, providing a datapoint given the assumptions and omissions of the model.  The authors make no claim to accuracy or precision: "This analysis has shown a possible method for modelling creep in a complete violin model by using a time hardening power law in a long-time perspective.   To be able to validate the results more research is necessary. The parameters used (Table 7.1) would have to be modified to accurately describe maple and spruce used in violins." (section 7.1.5 p. 83-84)

The dynamic analysis presented utilizes a sinusoidal input on each of the four strings.  The measurements illustrated in section 7.2.3 are of the relative mean displacement between the belly and back, and judging from an apparent lack of bias in the scale I presume relative to the violin with strings brought up to tune.  No mention of a stationary soundpost, so...

A statement from the conclusions section: "The analyses were performed successfully, but to get a better understanding of the properties influencing the results more extensive analyses are needed with more specified input data."

Nothing at all about tone or any relation to tone.  Results suggest some degree of accuracy, possibly fairly good depending on what you're looking for, but caveat emptor.  On the whole it's very nice work, worth a read, and a useful reference point for discussion.  Disclaimer - the above is the result of a fairly quick scan of the document rather than a rigorous evaluation, so again...more Latin idioms.

[David Burgess]

3 hours ago, reguz said:

David. I do not claim anything I just show what my research has shown me. Is there any wrong in that?

Perhaps, when it is done repeatedly enough, and with a style or format which resembles unsolicited "phishing" or "spam". It was you who started this thread with the claim,
" The arching is what makes your stringed instrument sound and function the way that it does. Without those curves (that is, with a flat top and back) your instrument wouldn't be able to stand up to the pressure of the strings"
was it not?

[Dr. Mark]

So - it was nice of Mr. Zuger to initiate the project and provide plates and drawings to the student authors of the thesis.  Since the plates were provided and apparently carved by Mr. Zuger, it shouldn't be a surprise that they have the geometric and other design principles he wants to express, and which the students duly describe using his terminology.  That's about it for his material contributions, so I don't think there's a basis for judging Tunlid and Varela's work and results based on how one may view Mr. Zuger's personality, or by his concepts of violin construction.  I don't see that the dissertation suggests, much less proves, anything one way or another about either.  Hope I'm not being a party pooper...

[Violadamore]

50 minutes ago, Dr. Mark said:

  Hope I'm not being a party pooper...

Not really.  Our latest Zugerfest has managed to expand itself to 7 pages already, despite your measured and well-reasoned responses.

For the rest of us, who have been engaging in these recurrent discussions with dear Mr. Zuger since 2013, it has at least, in these uncertain times, been a refreshingly predictable and nostalgic occurrence, something like hanging up a piñata at Christmas.   

OTOH, it is sobering to reflect that so many of our witty colleagues, who in earlier years would have added their penetrating observations to ours, are no longer present to join us in the festivities. 

[David Burgess]

10 hours ago, Violadamore said:

OTOH, it is sobering to reflect that so many of our witty colleagues, who in earlier years would have added their penetrating observations to ours, are no longer present to join us in the festivities. 

Uh oh. Are you implying that Reguz had them assassinated?
I'm switching from my regular tin foil hat, to my bullet-proof tin foil hat, just in case!

[reguz]

9 hours ago, David Burgess said:

Perhaps, when it is done repeatedly enough, and with a style or format which resembles unsolicited "phishing" or "spam". It was you who started this thread with the claim,
" The arching is what makes your stringed instrument sound and function the way that it does. Without those curves (that is, with a flat top and back) your instrument wouldn't be able to stand up to the pressure of the strings"
was it not?

Yes David. You're right, I was the one who started this thread.
The reason is that I do not share the view that the arching is there to support the pressure of the strings. I have also shown that several scientists are of that opinion.
I do not share their opinion and have shown with a vector diagram that it is the opposite. The vaulting bulges outwards under string load and centers = sound post does not move.
But why didn't I show the full text? Well, it was because I expected one of you to comment but you didn't. Instead, you show an ignorance of how things are just like the scientists. Unfortunately, it is then that these deceive you into believing something that is impossible, a downward movement in the centers. This affects the characteristics of the violin to a great extent and this is what my study is about. Using ONE specific arch shape can provide answers to how it can/must work

8 hours ago, Dr. Mark said:

So - it was nice of Mr. Zuger to initiate the project and provide plates and drawings to the student authors of the thesis.  Since the plates were provided and apparently carved by Mr. Zuger, it shouldn't be a surprise that they have the geometric and other design principles he wants to express, and which the students duly describe using his terminology.  That's about it for his material contributions, so I don't think there's a basis for judging Tunlid and Varela's work and results based on how one may view Mr. Zuger's personality, or by his concepts of violin construction.  I don't see that the dissertation suggests, much less proves, anything one way or another about either.  Hope I'm not being a party pooper...

Dr. Mark. It seem to me that you understand why we did this investigation that gave proof on what I expected. I do nothing about yours or others arching shape function. Do you know?

[David Burgess]

Endless circular arguments, and denials and accusations by raguz, as usual.

[Violadamore]

9 hours ago, David Burgess said:

Uh oh. Are you implying that Reguz had them assassinated?
I'm switching from my regular tin foil hat, to my bullet-proof tin foil hat, just in case!

Absolutely not in the least!         Rereading old threads makes me sad sometimes, is all. 

[jacobsaunders]

I have lost track here of what is being argued about, apart from who has the last word

[violins88]

It’s interesting that the thread has gone on so long. The original statement 

“the arching is what makes your stringed instrument sound and function the way that it does. Without those curves (that is, with a flat top and back) your instrument wouldn't be able to stand up to the pressure of the strings.” really is a non statement. I could say “ a wheel works because it is round.” True I guess, but not very enlightening.

We want to know WHICH arching works best. Enlighten us please.

 

[Dr. Mark]

14 hours ago, reguz said:

I do nothing about yours or others arching shape function. Do you know?

I'm not confident that I understand what you're asking about.  I guess what I use to define the arches on my violin.  I try to use arch height in the range of posted measurements; edge thickness and channel depth similarly, coupled with aesthetics, preferences expressed by the luthier who gets the last word in a discussion or has the most status, or who is closest to agreeing with me (so I don't have to change), images....  The arch shape is the result of planing the wood until I like the appearance or until it's sufficiently symmetric and I'm happy with it -  but if an arch is too resistent to my idea of happy I let it have it's way.  If you want to criticize I'm afraid I'm too easy to provide much amusement.

I will also reiterate a point about the sound post in the dissertation.  In static equilibrium all parts of the violin are at rest, so the point of reference for measurement can be chosen for convenience.  To compare the deformation of an unloaded structure to the same structure under static load a reference point is needed - the authors selected the sound post (I would need to review the document again to determine if they assumed incompressibility), but it could equally well be the center of the back plate, the bottom of the dog's waterdish, or so on.  They make no claim that stress has not displaced the sound post from the unstressed position given a different stationary frame of reference - specifically the center of mass for a free body, or perhaps the line between the chin rest and hand position for an approximate but quasi-practical vertical reference.

Edited September 20 by Dr. Mark
expansion of an idea and clarification

[Violadamore]

13 minutes ago, jacobsaunders said:

I have lost track here of what is being argued about, apart from who has the last word

Wunderbar!  My job here is done. 

 

10 minutes ago, violins88 said:

It’s interesting that the thread has gone on so long. The original statement 

“the arching is what makes your stringed instrument sound and function the way that it does. Without those curves (that is, with a flat top and back) your instrument wouldn't be able to stand up to the pressure of the strings.” really is a non statement. I could say “ a wheel works because it is round.” True I guess, but not very enlightening.

We want to know WHICH arching works best. Enlighten us please.

 

Since our most prestigious resident experts persistently claim that "best" is too subjective to be defined, as well as that sound is worthless (except when they are trying to charge extra for it     ), how can it possibly matter? 

[Peter K-G]

Robert, I claim that my violins are more powerful because i place the STLs at a narrower angle. They also have more resistance to the bow.

 

Question to the study:

Why was unusual plates used? 

Low freqencies, heavy top and light back.

[reguz]

Dear Peter K-G.  I belirve you mean by writing angle the "sector". Well if the sector say closes more the ability of structure in the sector become less flexible. The area becomes less. This may result in that the apllied energy, thus the action of bowinmg, in higher degree act on the less sector shape. If it is this yoo experiences I belive my explanation could be correct. I have thus far not studied any other say "free shape with STLs" only thoes of the underlaying geometry I found.

I do not undestand the quaestion "why was.... " and neither lLOw frequ ...

Sorry about this 

[reguz]

2 hours ago, violins88 said:

It’s interesting that the thread has gone on so long. The original statement 

“the arching is what makes your stringed instrument sound and function the way that it does. Without those curves (that is, with a flat top and back) your instrument wouldn't be able to stand up to the pressure of the strings.” really is a non statement. I could say “ a wheel works because it is round.” True I guess, but not very enlightening.

We want to know WHICH arching works best. Enlighten us please.

 

Dear violions88. If I was able to do what you aske for I certianly for long time ago would have done but as you must know I only study one specific structure and hope to learn fram that. However, there are specific conditions we find on all violins and these are described and it might be possible you have not tought about it. If you study the N Harris thesis carfully and undestand the result of his study of deformation youas well as Harris finally may come to the result that the sound ppst hold specific condition. Measuring deflection by string load is always better to do fron "ONE" structure instead of sevaral. Already that is important to withhold your undestanding to.

[reguz]

2 hours ago, Violadamore said:

Wunderbar!  My job here is done. 

 

Since our most prestigious resident experts persistently claim that "best" is too subjective to be defined, as well as that sound is worthless (except when they are trying to charge extra for it     ), how can it possibly matter? 

If I had the answer you certainly will get.

[David Burgess]

2 hours ago, Peter K-G said:

Robert, I claim that my violins are more powerful because i place the STLs at a narrower angle. They also have more resistance to the bow.

As far as I know, the "power" of a violin is still mostly assessed aurally by the players and the audience, with evaluation of sound by STL lines having no significant part.

[Peter K-G]

1 hour ago, reguz said:

I do not undestand the quaestion "why was.... " and neither lLOw frequ ...

Sorry about this 

[Peter K-G]

1 hour ago, David Burgess said:

As far as I know, the "power" of a violin is still mostly assessed aurally by the players and the audience, with evaluation of sound by STL lines having no significant part.

You are probably right. A box with strings, the player and the audience is all that's needed. All boxes are equally powerful

[martin swan]

Sorry but it seems to me to be the height of battiness to study the arching of violins in isolation.

Violins are extraordinarily complex objects in which everything constantly affects everything else - arching simply doesn't exist as an isolated phenomenon, it is inevitably, inextricably, intimately wedded to thicknessing, wood density, variations in string load, and the various points at which it's fixed. No two violins with the same arching will sound the same ...n unless perhaps made with 4mm ply.

In my rather Luddite world view, reguz's practice is antithetical to good violin-making. I haven't a clue what he's talking about but I know beyond a shadow of doubt that it's irrelevant to the construction of good sounding violins. That he should persistently return to Maestronet and pick fights with professional violin-makers is just darkly comical.

 

[David Burgess]

41 minutes ago, Peter K-G said:

All boxes are equally powerful

Really? Somehow, I'd been thinkin' that both aural assessments and measured sound levels had shown otherwise.