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Woodland

Boxy, honky nasal sound.

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27 minutes ago, GeorgeH said:

Yes, they were testing a 55 year-old Colin-Mezine. They do not discuss the appui or whether the top was already distorted. I have a number of 80-150 year-old violins, and none of the tops appear distorted, so I think that it is  a reasonable assumption to assume that the top of this violin was not distorted. 

Properly fit soundposts in violins don't fall when strings are tensioned. You have never observed this happening with a violin. Soundposts generally only fall when compression from string tension is removed. Thus, empirical observations support the conclusion of the paper.

Yeah, not so much.  The height of the appui, the angle of the strings over the bridge, the placement of the nut, and the height of the bridge are all variables that would directly effect the results here, as well as the fact the experiment was conducted in 90% RH.  The reality that I have never had a soundpost fall when an instrument is strung up is absolutely irrelevant as I have had soundposts loosen as an instrument is strung up....an observation confirmed by at least two very experienced makers on this thread.  Sorry, there is no relevance to this experiment in our discussion if we do not even know the measurements of the instrument in question.

It is also extremely unlikely that any 85 - 150 year old instruments would have no distortion.

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47 minutes ago, GeorgeH said:

 

They do not discuss the appui or whether the top was already distorted. I have a number of 80-150 year-old violins, and none of the tops appear distorted, so I think that it is  a reasonable assumption to assume that the top of this violin was not already distorted.

How would you have any idea whether the original top arching was distorted, without having taken measurements or templates when the instrument was first made?

George also wrote:  "Properly fit soundposts in violins don't fall when strings are tensioned. You have never observed this happening with a violin. Soundposts generally only fall when compression from string tension is removed. Thus, empirical observations support the conclusion of the paper."

Oh geez, I don't know how to interpret that, other than that your sample size and experience has been way below mine, and also well below that of the better restorers I have been around.

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49 minutes ago, Jerry Pasewicz said:

The fact that I have never had a soundpost fall when an instrument is strung up is absolutely irrelevant as I have had soundposts loosen as an instrument is strung up....an observation confirmed by at least two very experienced makers on this thread.

Millions of violins have had string tensions increased and decreased many many times. This would include violins of many different dimensions and ages. No one is ever warned about soundposts falling down when tightening strings, only when loosening strings.

It is reasonable to conclude that violin soundposts that are too short fall down when strings are loosened, not when they are tightened. 

34 minutes ago, David Burgess said:

Oh geez, I don't know how to interpret that, other than that your sample size and experience have been inadequate.

Well, I don't see anybody here with much more experience and sample size than I have jumping in to report that violin soundposts falling with strings under tension is a common occurrence. Performing a web search on soundposts falling only yields results of them falling when string tension is reduced or removed. And I can't find a report of a violin soundpost falling as string tension is increased, but there are many reports of them falling when string tension is reduced. 

If it happens, it must be an extraordinarily rare occurrence, and I would suspect that it is due to a contributing defect such as a detached bassbar.

34 minutes ago, David Burgess said:

How would you have any idea whether the original arching has distorted, without have taken measurements or templates when the instrument was first made?

OK, they don't appear visibly distorted.

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4 minutes ago, GeorgeH said:

Millions of violins have had string tensions increased and decreased many many times. This would include violins of many different dimensions and ages. No one is ever warned about soundposts falling down when tightening strings, only when loosening strings.

It is reasonable to conclude that violin soundposts that are too short fall down when strings are loosened, not when they are tightened. 

Well, I don't see anybody here with much more experience and sample size than I have jumping in to report that violin soundposts falling with strings under tension is a common occurrence. Performing a web search on soundposts falling only yields results of them falling when string tension is reduced. And I can't find a report of a violin soundpost falling as string tension is increased, but there are many reports of them falling when string tension is reduced. 

If it happens, it must be an extraordinarily rare occurrence, and I would suspect that it is due to a contributing defect such as a detached bassbar.

OK, they don't appear visibly distorted.

Where did anyone say soundposts fall under string tension???  You are arguing against an imaginary point of your own construction.

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1 hour ago, GeorgeH said:

The paper I linked to above shows that the top area around the soundpost compresses downward when strings are tensioned. In the illustration below (from the paper), the "+" areas are where the top distorts upward and the the "-" areas are where the top distorts downward.

 

distortion.jpg

The asymmetry of the effect on the front suggests that variation of construction could make a difference to the shape.

What would this 'movement' diagram look like if the back is very strong/thick and the front thin in the centre and thicker at the edges?  Other constructional variations are conceivable.

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8 minutes ago, Janito said:

The asymmetry of the effect on the front suggests that variation of construction could make a difference to the shape.

What would this 'movement' diagram look like if the back is very strong/thick and the front thin in the centre and thicker at the edges?  Other constructional variations are conceivable.

Could a back that is being 'stretched' when the strings are tensioned cause a  "squeezing-in" effect of the top plate at the C bout if the constructional circumstances are right. 

 

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12 minutes ago, Jerry Pasewicz said:

Where did anyone say soundposts fall under string tension???  You are arguing against an imaginary point....

It isn't imaginary at all. If stringing up a violin caused a soundpost to loosen, then there would be many reports of soundposts falling as strings were tensioned. Soundposts under compression by string pressure don't fall.

You wrote that "I have had soundposts loosen as an instrument is strung up....an observation confirmed by at least two very experienced makers on this thread."

If a violin soundpost commonly loosened as strings are tensioned up, then violins with soundposts that are too short or loosely fitted would be as likely to fall during string tensioning as they are when string tension is removed. However, this is clearly not the case, and empirically argues against the hypothesis that "soundposts loosen as an instrument is strung up."

The science supports the general observation that string tension increases pressure on the soundpost.

(Note: I am only referring to violins, and I am assuming tension on all 4 strings.)

 

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19 minutes ago, GeorgeH said:

1. Millions of violins have had string tensions increased and decreased many many times. This would include violins of many different dimensions and ages. No one is ever warned about soundposts falling down when tightening strings, only when loosening strings.

2. It is reasonable to conclude that violin soundposts that are too short fall down when strings are loosened, not when they are tightened. 

3. Well, I don't see anybody here with much more experience and sample size than I have jumping in to report that violin soundposts falling with strings under tension is a common occurrence. Performing a web search on soundposts falling only yields results of them falling when string tension is reduced or removed. And I can't find a report of a violin soundpost falling as string tension is increased, but there are many reports of them falling when string tension is reduced. 

 

1. .Sure, some scenarios are more common than others.

2. Have you invested much thought in why this is not always true?

3. Dude, put aside whatever lame web searches you have done, and learn how to get down to what really matters.

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6 minutes ago, David Burgess said:

1. .Sure, some scenarios are more common than others.

2. Have you invested much thought in why this is not always true?

3. Dude, put aside whatever lame web searches you have done, and learn how to get down to what really matters.

1) Yes, black swans happen.

2) Yes. If it happens, my hypothesis is that it is likely due to a contributing defect in the violin, and not a general phenomena. 

3) :D

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18 minutes ago, GeorgeH said:

It isn't imaginary at all. If stringing up a violin caused a soundpost to loosen, then there would be many reports of soundposts falling as strings were tensioned. Soundposts under compression by string pressure don't fall.

You wrote that "I have had soundposts loosen as an instrument is strung up....an observation confirmed by at least two very experienced makers on this thread."

If a violin soundpost commonly loosened as strings are tensioned up, then violins with soundposts that are too short or loosely fitted would be as likely to fall during string tensioning as they are when string tension is removed. However, this is clearly not the case, and empirically argues against the hypothesis that "soundposts loosen as an instrument is strung up."

The science supports the general observation that string tension increases pressure on the soundpost.

(Note: I am only referring to violins, and I am assuming tension on all 4 strings.)

 

Hard to know where to start.

Yes, you are likely imagining that soundposts are falling when the strings are tensioned.  I know of no time or have ever heard of that happening or anyone reporting it....that is imagination.  This point covers most of your argument....you are building your logic on a house of cards that no one said exists.

I am sorry you have not noticed soundposts loosen when tension has been applied,  but that does not change reality and observations of long time professionals that know of these things happening..It is what it is..regardless of what you believe is science.

 

 

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20 minutes ago, GeorgeH said:

1) Yes, black swans happen.

2) Yes. If it happens, my hypothesis is that it is likely due to a contributing defect in the violin, and not a general phenomena. 

3) :D

You need to work on your hypothesis if it does not align with available facts.

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39 minutes ago, GeorgeH said:

Millions of violins have had string tensions increased and decreased many many times. This would include violins of many different dimensions and ages. No one is ever warned about soundposts falling down when tightening strings, only when loosening strings.

It is reasonable to conclude that violin soundposts that are too short fall down when strings are loosened, not when they are tightened. 

Well, I don't see anybody here with much more experience and sample size than I have jumping in to report that violin soundposts falling with strings under tension is a common occurrence. Performing a web search on soundposts falling only yields results of them falling when string tension is reduced or removed. And I can't find a report of a violin soundpost falling as string tension is increased, but there are many reports of them falling when string tension is reduced. 

If it happens, it must be an extraordinarily rare occurrence, and I would suspect that it is due to a contributing defect such as a detached bassbar.

OK, they don't appear visibly distorted.

Any reference to “a web search” is a serious if not greivious error of logic, while there are many bits of information, the best stuff, is for the most part absent in the content. Real time . 

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1 minute ago, Jerry Pasewicz said:

Hard to know where to start.

Yes, you are likely imagining that soundposts are falling when the strings are tensioned.  I know of no time or have ever heard of that happening or anyone reporting it....that is imagination.  This point covers most of your argument....you are building your logic on a house of cards that no one said exists.

I am sorry you have not noticed soundposts loosen when tension has been applied,  but that does not change reality and observations of people that know of these things happening....regardless of what you believe is science.

 

 

Nice job with the heavy lifting BTW.... I do know that in times long past..... one of my experiments was to set up a violin , without a sound post, just to see, not a forever long time but long enough, to my surprise, the violin ...did not simply implode, but also sounded weak. My conclusion was that overall the box is strong, but not immobile,and yes it would be entirely possible for the post pressure to become less under the right conditions. seems like the only truly accurate way to quantify the preasure changes would be with a series of piezoelectric sensors. Maybe anima or some other could incorporate one in a carbon post.,,, as an analytic tool .... would love to see the outcomes. 

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2 minutes ago, James M. Jones said:

Nice job with the heavy lifting BTW.... I do know that in times long past..... one of my experiments was to set up a violin , without a sound post, just to see, not a forever long time but long enough, to my surprise, the violin ...did not simply implode, but also sounded weak. My conclusion was that overall the box is strong, but not immobile,and yes it would be entirely possible for the post pressure to become less under the right conditions. seems like the only truly accurate way to quantify the preasure changes would be with a series of piezoelectric sensors. Maybe anima or some other could incorporate one in a carbon post.,,, as an analytic tool .... would love to see the outcomes. 

Thanks, I will keep you updated.  

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I hope by now readers can see how the string tension can impose several different kinds of stresses the neck joint and plates.

I further hope readers can see the implications of using a shallow sting angle over the bridge  (high nut and high saddle) which reduces the downward load on the top and by not attaching the string to an end pin-compression loading of the top causing it to buckle and bend, and tension loading of the back causing it to stretch are avoided.

I even further hope readers can see the implications of not having  adult supervision. 

No 29 side view small.jpg

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1 hour ago, GeorgeH said:

 Performing a web search on soundposts falling only yields results of them falling when string tension is reduced or removed.

I wouldn't suggest a general web search as the best form of elucidation, when it comes to violin making, restoration, or fiddle physics. The crap-to-value ratio is rather frightful.

Heck, I put up a totally satirical and absurd video on bridge fitting, and was blown away by how many people took it as being serious.

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Re: soundpost becoming looser under string tension...

As I stated, it is not something I personally have observed, and for sure most violins do not behave that way.  There are experienced voices out there that seem to be implying that there are a few, while somehow being a bit indirect about it.

The analysis of what it would take for string tension to cause reduced soundpost pressure is nowhere near the simplicity of the diagrams I have posted so far, and not something I can do without extremely detailed finite element models.  However, I do see the possibilities.  I suspect that high arching, with a stiff area under the bridge (either arched or thick grads) would be most important, and a low arched back would help (less flattening under tension).  

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To me, the obvious scenario in which a soundpost might loosen under tension would be a relatively undistorted top arch introduced to the combination of a high nut and a low string angle. Plus what Don suggests, stiff high central arch ...

We would be introducing enough torque to make the arch buckle (upwards) and yet not applying enough downbearing through string angle to counteract it.

I'd have to say that in my experience (less than Jerry's but still large), posts that have been in an instrument for any length of time (decades) are always tight, and require considerably more force to dislodge them than any post I would ever fit. So Jerry's scenario would likely be something that could only happen with a freshly fitted post.

OTOH I abhor the practice of moving posts without taking off all the string tension ... yet this is the only way one might observe this "loosening of the post under tension". 

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20 hours ago, Don Noon said:

 

I don't see any ideal point of anything from a structural point of view...

 1131969647_Archingdeformation.jpg.b28eb6e2bbfad00177aadc098782ca63.jpg

Don, thanks for this drawing ... very helpful

From a woodworking perspective, it seems that trying to get the arching into a straight line from the top block to the bridge would help to resist this deformation ...?

 

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13 hours ago, Jerry Pasewicz said:

I may have missed something in the article, but weren’t they testing a Collin-Mezin from 1925?  This would mean that the arch was likely already distorted, and as a Collin-Mezin the appui is lower than the modern norm. 

Collin-Mézins, like so many of the better French trade instruments, tend to have a much lower nut position and overstand, and a consequently higher string angle.

But according to our discussions of torque, while this would produce more downbearing on the table it would produce less torque on the top block.

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19 hours ago, Ken_N said:

I haven't read this whole thing; it seems that the string angle, the bridge height, the placement of the the top of the nut, and even the height of the saddle are the only things that matters.  The appui just happens.

I agree (still)! Though it's also a product of your desired action - but that's maybe a bit more standardised than other elements.

From the discussion so far, it seems that you could illustrate visually all the forces at work in a violin, but your drawing need never include any of the wood between the top of the table and the top of the fingerboard. Don will correct me if I'm wrong ...!

To that extent, a baroque neck is exactly like a modern neck. The modern neck just offers ease of replacement and more resistance to failure.

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2 hours ago, martin swan said:

To me, the obvious scenario in which a soundpost might loosen under tension would be a relatively undistorted top arch introduced to the combination of a high nut and a low string angle. Plus what Don suggests, stiff high central arch ...

We would be introducing enough torque to make the arch buckle (upwards) and yet not applying enough downbearing through string angle to counteract it.

I'd have to say that in my experience (less than Jerry's but still large), posts that have been in an instrument for any length of time (decades) are always tight, and require considerably more force to dislodge them than any post I would ever fit. So Jerry's scenario would likely be something that could only happen with a freshly fitted post.

OTOH I abhor the practice of moving posts without taking off all the string tension ... yet this is the only way one might observe this "loosening of the post under tension". 

Well there is an obvious point I failed to take into account.  How could anyone feel that the post has loosened after string tension is on,  if you do not try to move the post after string tension is on?  I find things change, and sometimes pretty significantly,  when all the string tension is taken off..so knowing what the post movement affected and to what degree is impossible.

1 hour ago, martin swan said:

Don, thanks for this drawing ... very helpful

From a woodworking perspective, it seems that trying to get the arching into a straight line from the top block to the bridge would help to resist this deformation ...?

 

Almost making the initial arch on the top look like the arch in red from the back and vice versa makes sense, and kinda elegant.

1 hour ago, martin swan said:

Collin-Mézins, like so many of the better French trade instruments, tend to have a much lower nut position and overstand, and a consequently higher string angle.

But according to our discussions of torque, while this would produce more downbearing on the table it would produce less torque on the top block.

My thoughts exactly.  If the effect was to be measured, this would not be the one to use as the increased  pressure from the bridge would have little tourque  to support the arch .  Another pretty important point that was lost and part of my thinking for the initial comment; “nasal” is a characteristic of many of the French violins you reference and referenced in the op.....this is a pattern in my experience.  Nasal - low overstand and low nut position.

1 hour ago, martin swan said:

I agree (still)! Though it's also a product of your desired action - but that's maybe a bit more standardised than other elements.

From the discussion so far, it seems that you could illustrate visually all the forces at work in a violin, but your drawing need never include any of the wood between the top of the table and the top of the fingerboard. Don will correct me if I'm wrong ...!

Almost...the string, not the top of the fingerboard.

To that extent, a baroque neck is exactly like a modern neck. The modern neck just offers ease of replacement and more resistance to failure.

Except for the minor bit and  “the appui just happens”  (coming from someone that regularly makes appuis happen) I agree entirely........fish that tambourine out of the camp fire.

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12 hours ago, GeorgeH said:

If a violin soundpost commonly loosened as strings are tensioned up, then violins with soundposts that are too short or loosely fitted would be as likely to fall during string tensioning as they are when string tension is removed. However, this is clearly not the case, and empirically argues against the hypothesis that "soundposts loosen as an instrument is strung up."

The science supports the general observation that string tension increases pressure on the soundpost. 

I won't be so rigid in this point. Just regarding to my personal experience in adjusting soundposts (quite a lot;)) it's the majority moving easier with the string tension of A and E released a bit (and that's usually recommended to avoid damage to the inside belly). A very few didn't show a significant difference if strings were released or not, and when I'm remembering correctly, those had rather thick and stiff graduated tops.

More from hearsay I was informed that new made instruments (of quality) need a longer post fitted after a certain settling period of some months or a year, what would indicate that either the top center is moving upwards, the back downwards or both. I'm usually not handling new made violins except some chinese in the past (and those often needed longer soundposts of course), maybe makers of new insruments can comment on this.

So I won't deny that there are some instruments with a post getting looser under string tension, but this seems to be so unusual that it's been reported as a sort of oddity. Some reasons for this phenomena were mentioned before (stiff center, maybe due to graduation or patches, a special arching or a flat strong bottom), without knowing more of the particular instruments it's not possible to tell a reason.

But remembering the starting point of the discussion, that a violin sounding boxy, honky, nasal needs an appui (meaning overstand) of 6 instead of 5 mm to strengthen the top and make it vibrate more freely, this seems to be stressing a rare observation quite excessive. There are so many other variables involved (described many times before in this thread, I don't want to repeat them all). I personally have some ideas what can make an instrument make sound this way, probably many others here have them, too, but won't dare to generalize them without seeing the particular circumstances.

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As has been discussed, raising the appui (I don’t think anyone mentioned 5 to 6, or that it would vibrate more freely, or that this was the only thing happening) has an effect on many things as a consequence including string angle, bridge height, nut position, heel compass, etc. these taken as a whole will dramatically change the the way an instrument feels to the player, it is not insignificant; the effect of the torque on the top is only one of many.   At the same time, we now can agree that this real, whether it is to the degree of loosening the post with string tension or not is irrelevant.  It is in the mix of what is happening and if we really want to understand, why ignore it?

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