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Plate Vibration Modes

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Interesting that there is still a huge interest on plate modes, although almost everyone working on this topic  came to the conclusion that plate modes and good sound are a coincidence rather than a correlation. Is it just because we can’t measure other things as easy on a free plate (besides weight)? It is a symptom of modern thinking that there has to be something measured, even if it has no impact. 

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6 hours ago, Michael Szyper said:

It is a symptom of modern thinking that there has to be something measured, even if it has no impact. 

Although "measurements" might be more of a modern thing, I think it's more due to the availability of equipment that can be used to measure things, rather than a fundamental shift of human nature.  We're always looking for patterns that we think mean something, especially if we're trying to get a result we want.   And if you look hard enough, often you'll think you  see a pattern, even if it isn't really there.

Mentioning "correlations" brings back to mind a fancy formula for predicting signature modes from plate weight and taptones.  I plugged in my plate and instrument data, and the correlation to actual signature modes was WORSE than if I just used a fixed value for them.

And that's just the signature modes, which are only a small part of "good sound".  The rest is all in the higher modes, which have even less to do with the plate taptones than even the poorly correlated signature modes.

Still, a maker has to do SOMETHING to decide on the construction details.  Plate weight and taptones are simple and quick, and make sense to me to use them... but with the realization that it doesn't mean all that much, and not worth fussing over.  Wood, arching, and lots of other stuff probably mean more.

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8 hours ago, Michael Szyper said:

Interesting that there is still a huge interest on plate modes, although almost everyone working on this topic  came to the conclusion that plate modes and good sound are a coincidence rather than a correlation. Is it just because we can’t measure other things as easy on a free plate (besides weight)? It is a symptom of modern thinking that there has to be something measured, even if it has no impact. 

I think one who engages in this, for better or worse, needs to wade through tons of crap in order to eventually come to a system that works for them.

I think the emphasis on bringing numbers and science into the fray has had some benefits, but for the most part has just acted like some false lead to follow, related to tap tones at least.

again without having a benchmark that is truly defined, we pretty much have the "I want mine to sound like a Strad" thing as the "goal" , which I find funny that there is some supposed scientific system for a benchmark that is undefined.

I think it's pretty obvious when you've hit the mark in that if you are honest, and it sounds good to you, it will sound good to others, when in a room with other instruments, it becomes apparent to you and others where the violin sits in the tone category, once you get to that "really great" sound level, after that it's pretty subjective who might choose what out of say 5 really great sounding instruments.

To me properly constructing a violin is hard enough without throwing in a bunch of potentially time wasting ritualistic dare I say nonsense 

There are SO many things interacting together that to me it is like focusing on a pile of sand on the shore of the beach thinking that you will use that to describe what going on with the ocean. It's part of it, but just one small part.

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another blurb I will throw out there in the realm of unscientific thinking.

For me, a good way to think about this is that what I'm doing is building a wooden hot rod. It's a machine and I'm trying to eek out horsepower though tuning and quality parts and components.

and seeing how it's an old machine design in a long ago time, that is how I approach it. There is no digital obd mapping of the intake, its all old school analog carbs that you use your ears and you hands to hear and feel stuff that lets you know you've got it just right.

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2 hours ago, Don Noon said:

Although "measurements" might be more of a modern thing, I think it's more due to the availability of equipment that can be used to measure things, rather than a fundamental shift of human nature.  [...]

I agree it's not a shift of human nature.

But I think it is a general large shift of culture. If you look at anything made in the 17th century and compare it to almost anything made in the 20th century, you'll see evidence of a profound shift in the way things are sized and put together.

What drives the differences is that the later culture of large scale commercial production needs repeatabilty, interchangability, predictability.  

The old work uses skilled craftsmanship to uniquely size and fit parts, one unique part to the next unique part.

The newer work escapes the constraints of the old approach by fitting and sizing by compliance to a plan.  This relies on chasing away the uniqueness of individual parts.  So making consistently to a plan, within required tolerances, is now the priority.  And this rests on the predictability or precision of measures, recipes, materials, etc.

Oddly, even in areas where a 'measures and tolerances' approach isn't so much actually needed, it seems to have permated the entire culture of making and designing things.

I tend to believe this is the root driver behind the large degree of differnce seen in the physical and human presence of virtually any object made before or after 1800 +/- 40yrs.

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3 hours ago, Don Noon said:

Although "measurements" might be more of a modern thing, I think it's more due to the availability of equipment that can be used to measure things, rather than a fundamental shift of human nature.  We're always looking for patterns that we think mean something, especially if we're trying to get a result we want.   And if you look hard enough, often you'll think you  see a pattern, even if it isn't really there.

Mentioning "correlations" brings back to mind a fancy formula for predicting signature modes from plate weight and taptones.  I plugged in my plate and instrument data, and the correlation to actual signature modes was WORSE than if I just used a fixed value for them.

And that's just the signature modes, which are only a small part of "good sound".  The rest is all in the higher modes, which have even less to do with the plate taptones than even the poorly correlated signature modes.

Still, a maker has to do SOMETHING to decide on the construction details.  Plate weight and taptones are simple and quick, and make sense to me to use them... but with the realization that it doesn't mean all that much, and not worth fussing over.  Wood, arching, and lots of other stuff probably mean more.

Of course a maker has to do something to decide how to go on. The best thing we still can do is rely on a good method we learned from an excellent maker (in the best case), rely on gut feelings and develop slowly. As i read your posts about arching concepts it seems that you have a damn good feeling which elements an arching should contain and which not. Besides of that, a scientific approach is very useful in order to understand which role the parts of a violin play (that‘s what we call finite element analysis?). To derive design concepts based on this knowledge is a truly long, hard way. 

 

1 hour ago, jezzupe said:

To me properly constructing a violin is hard enough without throwing in a bunch of potentially time wasting ritualistic dare I say nonsense

This concept would help most of us to save time and go forward. But almost everybody of us has a more or less developed tendency towards spirituality, also in violin making. 

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6 hours ago, David Beard said:

I agree it's not a shift of human nature.

But I think it is a general large shift of culture. If you look at anything made in the 17th century and compare it to almost anything made in the 20th century, you'll see evidence of a profound shift in the way things are sized and put together.

What drives the differences is that the later culture of large scale commercial production needs repeatabilty, interchangability, predictability.  

The old work uses skilled craftsmanship to uniquely size and fit parts, one unique part to the next unique part.

The newer work escapes the constraints of the old approach by fitting and sizing by compliance to a plan.  This relies on chasing away the uniqueness of individual parts.  So making consistently to a plan, within required tolerances, is now the priority.  And this rests on the predictability or precision of measures, recipes, materials, etc.

Oddly, even in areas where a 'measures and tolerances' approach isn't so much actually needed, it seems to have permated the entire culture of making and designing things.

I tend to believe this is the root driver behind the large degree of differnce seen in the physical and human presence of virtually any object made before or after 1800 +/- 40yrs.

Strad's use of internal molds and patterns was a modern standardization move away from the older methods.

Maybe Strad had shelves stacked with shaped top and back plates, rib assemblies, necks etc. and they just grabbed interchangeable parts and assembled them.

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33 minutes ago, Marty Kasprzyk said:

Strad's use of internal molds and patterns was a modern standardization move away from the older methods.

Maybe Strad had shelves stacked with shaped top and back plates, rib assemblies, necks etc. and they just grabbed interchangeable parts and assembled them.

Not as much as would be the case if his body outlines truly derived directly from the mold shapes.  But the don't really.  Strad is making the old way.  His outlines don't come straight from the mold, but instead are fitted in relation to the sides only after they are removed from the mold, pinned, twisted, pushed around, and then clamped to the board.

The molds do end up standardizing the outlines.  They remain much more varied.

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I think the way Davide is using mode information is pretty on target, again another well done video. 

One of the most important things you can learn from this is where to hold and where to tap to get the right information response. Pay close attention to his flexing and range of motion in that flexing

I think the addition of the microphone to amplify the response is very important in that what we are listening for is a "clear" {as is the same pitch is heard true in succession} percussive thud that does not emanate any "ringing" tone or long decay in general. The mic amplification lets you really hear it. So, until the entire thing is put together, you're making bongos.

 

 

 

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On 6/16/2019 at 4:44 AM, David Beard said:

Yes. The wood pick should be lively and talkative.  And in the traditional billet form it natirally and incidentally have clear pitch.     Just a matter of an elastic material and a shape that gives some mode enough freed to flex, good  'containment', and defined length.

But in making, seeking out well pitch defined resonances is counter to the main behaviors a  violin needs.  In my opinion.

Okay, so you agree that we should look for lively and talkative wood pieces that in form of a wedge billet gives a clear pitch. The next question then would be - how do you avoid the strong and clear M5, that is a consequence of that?

 Another question would be - Is there really makers that think free plate modes are the main behavior in violins.

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"how do you avoid the strong and clear M5"

m5 seems to relate to the longitudinal "bow" flex, in simple terms, it is easy to leave the "spine" ie. the center areas running the length of the plates too thick, or more, too strong

By having a spinal area that is too strong the throw range of the M5 motion is short and tight. The M5 is one that you want some energy loss through "wobbly" "lack of stiffness" or not having "over stiffness" this weakness will add softness and reduce "shrill" 

Again, don't think of Modes as pitch or frequency {even though they correspond} think of them as ways the plates move,and that by "flexing for stiffness" you are creating an exaggerated motion of the Mode motions with your hands, again, looking for a certain level of stiffness and elasticity. That in my mind is reached by being guided by the response of the plate to manipulations that do seem to fall into target frequency pitch when everything is "right" or close to right, what ever right is....I define it by a plate that flexes and recoils the way I want it to when I say it's done, not by it's pitches when tapped in certain areas, all though they do seem to go hand in hand, I will use taps as "verification" that my hands are correct.

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2 hours ago, Peter K-G said:

Another question would be - Is there really makers that think free plate modes are the main behavior in violins.

I'm sure there are some out there.  I'm not one of them.  

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3 hours ago, Peter K-G said:

Another question would be - Is there really makers that think free plate modes are the main behavior in violins.

Yes, there are many. I am not one of them either, except that I think combinations of measured frequency and weight can provide better stiffness information than I can reliably and repeatedly do. flexing with my hands.

As a long-time "gym rat", I am very much aware of how perceptions of resistance can change from day to day.

Maybe gravity changes from day to day, but that hasn't been my conclusion, so far. ;)

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4 hours ago, Peter K-G said:

Okay, so you agree that we should look for lively and talkative wood pieces that in form of a wedge billet gives a clear pitch. The next question then would be - how do you avoid the strong and clear M5, that is a consequence of that?

 Another question would be - Is there really makers that think free plate modes are the main behavior in violins.

No need to avoid, just don't try to grab on, clarify, change, control, or define any particular resonance.  Go about the biz of making a plate.  Don't make the plate crazy thick or thin.  Flex the plate.  Does it flex smoothly and evenly?  Keep it simple.  Make a beautiful traditional plate.  Leave it at that.

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On 6/16/2019 at 10:03 AM, Don Noon said:

Although "measurements" might be more of a modern thing, I think it's more due to the availability of equipment that can be used to measure things, rather than a fundamental shift of human nature.  We're always looking for patterns that we think mean something, especially if we're trying to get a result we want.   And if you look hard enough, often you'll think you  see a pattern, even if it isn't really there.

Mentioning "correlations" brings back to mind a fancy formula for predicting signature modes from plate weight and taptones.  I plugged in my plate and instrument data, and the correlation to actual signature modes was WORSE than if I just used a fixed value for them.

And that's just the signature modes, which are only a small part of "good sound".  The rest is all in the higher modes, which have even less to do with the plate taptones than even the poorly correlated signature modes.

Still, a maker has to do SOMETHING to decide on the construction details.  Plate weight and taptones are simple and quick, and make sense to me to use them... but with the realization that it doesn't mean all that much, and not worth fussing over.  Wood, arching, and lots of other stuff probably mean more.

Colin Gough has shown with a finite element analysis that free plate modes 1, 2 & 5 morph into low frequency "signature modes" when the plates are attached to then ribs.  And George Bissinger  has shown that there is little correlation between the frequency of signature modes and violin quality anyway.  And you have often mentioned that the high frequency range is more important than the low frequency range and that the idea of plate tuning (M1, 2, 5) is of little merit.  Others have also abandoned the idea of plate tuning to frequency targets.

But does this suggest that "plate tuning" should be done for much higher frequency plate modes: M10, 15... whatever instead of the lower ones?

I'm wondering if "plate tuning" is not worthwhile or whether enough mode targets have been used in the past.

I'm guessing that if you were trying to duplicate plates then many mode frequencies have to be matched not just modes 1, 2 and most often just mode 5.

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6 hours ago, David Burgess said:

Yes, there are many. I am not one of them either, except that I think combinations of measured frequency and weight can provide better stiffness information than I can reliably and repeatedly do. flexing with my hands.

As a long-time "gym rat", I am very much aware of how perceptions of resistance can change from day to day.

Maybe gravity changes from day to day, but that hasn't been my conclusion, so far. ;)

Oh come on David your flexing in your picture now. The bicep 1 flex

by the way ,which is why I've slowed down a bit, giving my self a little more time to live with the graduation process, as I do find that one day the plate will feel this way, and then the next day it will feel another, so I like to be quite slow a deliberate about the last 5 days or so that I may be working on a plate, knowing that I could probably finish it in 1, but I like to have extra time with it to do just that, be sure of myself and my flexyness as my feedback response from my hands and upper body in general can change or feel different during the process and I may change my mind about an area or two.

I know long ago I had talked about the flexy thing, we even had someone post a link to some pressure sensitive gloves that could read fingertip pressure and all of that.

I do wish there was some more concrete literature, discussions, research, dissertations or what not about what I call "building to or for stiffness" 

I like to think of it as a Tai Chi like exercise routine that has to go through all the motions, but I do wish there was some better way for us all to quantify it in some language or series of "moves" .

All most like we all have to film ourselves when we are in the final stages, showing all the flexercise moves and explain why we are doing what we are doing and perhaps more importantly why or what we think it is telling us.

I'm building a classical guitar that's going to Italy, keeping in mind that I build guitars based off internal mold like violin, and they are arched, if I can find the time, maybe I will make a "I don't care what you people think" video explaining what I do and why I think I'm doing it.

I know "we" have had these discussions before, but there has not been much discussion or show and tell related to this "flexing stuff" , so maybe I can make one and you guys can laugh and pick it apart, could be fun.

 

 

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7 hours ago, David Beard said:

No need to avoid, just don't try to grab on, clarify, change, control, or define any particular resonance.  Go about the biz of making a plate.  Don't make the plate crazy thick or thin.  Flex the plate.  Does it flex smoothly and evenly?  Keep it simple.  Make a beautiful traditional plate.  Leave it at that.

I Promise

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2 hours ago, David Beard said:

Can't tell if it's stiff?  Uhh...

Apparently there are pills for that.:rolleyes: 

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12 hours ago, Marty Kasprzyk said:

But does this suggest that "plate tuning" should be done for much higher frequency plate modes: M10, 15... whatever instead of the lower ones?

I'm wondering if "plate tuning" is not worthwhile or whether enough mode targets have been used in the past.

I'm guessing that if you were trying to duplicate plates then many mode frequencies have to be matched not just modes 1, 2 and most often just mode 5.

Higher plate modes = far more complexity and variation = even farther from what happens in the assembled instrument, once the plates are glued to the ribs and soundpost placed.  Since the relation between the low modes of the free plate and the low modes of the assembled instrument is pretty poor, if you go higher, it's going to be even worse.

Unless you have the same wood properties and same arching, there will be some built-in barriers to duplicating plate modes.  Even if you could make that happen, I suspect that the end result would be dissimilar due to damping properties, local variations, or perhaps some of the other dozen or so wood properties that are difficult to measure.

This whole idea of matching free-plate modes to some gold standard looks to me like a dead-end with an infinite number of side streets that are also dead-ends.  You could spend a long time in there; I'd rather not.

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1 hour ago, Don Noon said:

[...]  You could spend a long time in there;[...].

Such an entertaining way to feel one is achieving something.  And you get to use cool gadgets, and pretty graphs and numbers, etc.

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22 hours ago, David Burgess said:

Yes, there are many. I am not one of them either, except that I think combinations of measured frequency and weight can provide better stiffness information than I can reliably and repeatedly do. flexing with my hands.

I knew it, you're one of those pl***t*ne*s

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1 hour ago, David Beard said:

Such an entertaining way to feel one is achieving something.  And you get to use cool gadgets, and pretty graphs and numbers, etc.

After making a few more instruments I forget what the earlier ones were doing.  Those pretty graphs and numbers make pretty good records.

Some runners run races just for the fun of it.  Others record their times to see if they are improving.

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Hi Marty,

I sort of get that motivation.  But if you record the number and size of trees in the parking lot where you race, is that 'recording your progress'?

 

 

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Violinmaking isn't that much like a race... how do you even quantify "progress"?

To me, the biggest problem in documentation is recording exactly what the arching is... not just the height and a few selected templates, but exactly where the convex and concave zones are, what the radii are, inflection points, and all of that.  Although I can't present any quantifiable "progress" (other than competition tone awards), I feel that my work got better after I spent a long time studying the arching of good violins in 3-D, either in person or from plate casts. 

You can document plenty of stuff, but the problem is deciding what matters and finding ways to document that.  Since I don't have a good way to document arching, I just try to study at as many good ones as possible, and hope it sticks in my brain.

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