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Graduation border near endblock area


MJ Kwan
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Anyone have specific feelings or reasonings for graduating right up to the edges of the endblock vs leaving a big ol ledge straight across?

Diagram here:

http://wp.me/a4i09z-Cb

 

Great Question, M J Kwan!

I've used both methods, and still, I cannot recommend one method over the other...

 

I will be curious what other makers say about this, and what their preferences are.

Sorry that I do not have an answer for you - but this ought to be interesting...

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Anyone have specific feelings or reasonings for graduating right up to the edges of the endblock vs leaving a big ol ledge straight across?

Diagram here:

http://wp.me/a4i09z-Cb

There was a long thread about this years ago,

http://www.maestronet.com/forum/index.php?/topic/323615-sacconi-plateu/?hl=saconni#entry501362

My view ist that this so called “plateu" (sic) which is not even a plateau at all in any sense of the word, can be found in Saconnis book, but not in any old violin that I have ever opened. i.e. “red herring”

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I do neither, but have some unverified acoustic ideas that lead me to thin out more slowly away from the neck block and more quickly from the lower block.  Structurally, the string height, overstand, and fingerboard thickness put the load line quite far above the neck block, therefore placing higher compressive load on the top near the neck block, and a good reason to try to spread out the loads with more wood to avoid having the arching bubble up under the fingerboard.  In addition, the shape of the top long arch means the wood near the block won't be longitudinal grain (assuming you're not a bender), and another reason to make the sloped area thicker.

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I do neither, but have some unverified acoustic ideas that lead me to thin out more slowly away from the neck block and more quickly from the lower block.  Structurally, the string height, overstand, and fingerboard thickness put the load line quite far above the neck block, therefore placing higher compressive load on the top near the neck block, and a good reason to try to spread out the loads with more wood to avoid having the arching bubble up under the fingerboard.  In addition, the shape of the top long arch means the wood near the block won't be longitudinal grain (assuming you're not a bender), and another reason to make the sloped area thicker.

Would this mean that perhaps one would not want much, if any, recurve in the longitudinal arch (at the top block) ?

Also, what do all of you think of the wide openings for a top block in the various moulds of Stradivari ?

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Would this mean that perhaps one would not want much, if any, recurve in the longitudinal arch (at the top block) ?

I don't see any significant recurve in most Cremonese long arches, other than the continuation of the channel.  It looks fairly straight as it approaches the block.  Structurally that makes sense.
 

Also, what do all of you think of the wide openings for a top block in the various moulds of Stradivari ?

Wide top blocks also make sense to try to spread out the load a bit.  I think it's fairly common among good modern makers, too.

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Funny, even when the arching is fairly full to the ends, old violins often don't have that deep sudden scoop, so there isn't such a distinct platform.

 

I took a picture of the top block area of a violin belly recently. This isn't a particularly flat arched fiddle, but the scoop and edge are worked so that there's a smooth line inside and out.  I have had to consciously work the outside down more than I learned at school to do, in order to make this shape. I think it's very light, strong and supple. 

post-30909-0-64574300-1443473984_thumb.jpg

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When I read all those answers I do not understand why you all are talking about acoustics when it is about dynamic behaviour of a structure. Before sound is produced we have a dynamic behaviour to consider. This means that the structure itself is the main problem to Control. The acting compression forece on the end block compresses a lot of structure to buckle. Also structure beside the end blocks are involved in this process. Buckling itself produces a kind of bending, not as it is by a moment of force acting one a structure like a beam that is loaded between to supporting walls.

It is important to have a notion on how and whre the structure in front of the end block and beside the end block hold a specific rigidness in that process. The reacting structure on the arching produceses the not being a striaght line structure that join the convex arching shape of the spehical bout shape with the concave shape of the C-bout. I have been able to show that such straight line structural condition is possible to construct by geometry, this aplayable to make. When we have acces to these specific location of structural quality we become able to contriol the behaviour of the dynamic spherical bout shape that produce accoustic result. So when you as a maker know all this you are able to control the acoustic outcome. The shape of the structural condition around the end blocks thus is an important structure to consider to shape otherwise you are not able to controll the important behavior of the dynamic. Hope this explain something to consider.

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I graduate the thickness right up withing 3mm of the block perimeter, for probably no other reason than getting rid of some dead weight. My thought is any additional wood left in this area creates a stiff region coupled to the block that  will reduce the vibrating area of the plate.

Has anyone experimented with a finished violin with the Cremonese "shelf", comparing the tone before and after removing the shelf so more of the plate vibrates?

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Has anyone experimented with a finished violin with the Cremonese "shelf", comparing the tone before and after removing the shelf so more of the plate vibrates?

I found it was a good way to remove weight from violin wood, working both neck and tail ends to possibly lose 10 gr. of weight but more than likely 6-7 grams.  Didn't really notice any tone difference after reassembly as I was trying to eliminate a wolf tone b on the a, d and g strings.  Wolf sound didn't get better or go away until wood was removed from neck profile, thus even more weight removal.  Is the violin ready for helping me start a small bon fire in the backyard?  Yes, very close.     

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I graduate the thickness right up withing 3mm of the block perimeter, for probably no other reason than getting rid of some dead weight. My thought is any additional wood left in this area creates a stiff region coupled to the block that  will reduce the vibrating area of the plate.

 

While I have no hard evidence to refute this idea, I do believe that there can be too much vibrating area.  Otherwise there would be lots of great 15" violins.

 

When I first started making violins, I graduated out as far as possible in all directions, with the same idea that more is better.  Now I don't, and I think it's an improvement.

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When I read all those answers I do not understand why you all are talking about acoustics when it is about dynamic behaviour of a structure. Before sound is produced we have a dynamic behaviour to consider. This means that the structure itself is the main problem to Control. The acting compression forece on the end block compresses a lot of structure to buckle. Also structure beside the end blocks are involved in this process. Buckling itself produces a kind of bending, not as it is by a moment of force acting one a structure like a beam that is loaded between to supporting walls.

It is important to have a notion on how and whre the structure in front of the end block and beside the end block hold a specific rigidness in that process. The reacting structure on the arching produceses the not being a striaght line structure that join the convex arching shape of the spehical bout shape with the concave shape of the C-bout. I have been able to show that such straight line structural condition is possible to construct by geometry, this aplayable to make. When we have acces to these specific location of structural quality we become able to contriol the behaviour of the dynamic spherical bout shape that produce accoustic result. So when you as a maker know all this you are able to control the acoustic outcome. The shape of the structural condition around the end blocks thus is an important structure to consider to shape otherwise you are not able to controll the important behavior of the dynamic. Hope this explain something to consider.

We're talking about acoustics because its whole damn point of building violins?

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When I read all those answers I do not understand why you all are talking about acoustics when it is about dynamic behaviour of a structure. Before sound is produced we have a dynamic behaviour to consider. This means that the structure itself is the main problem to Control. The acting compression forece on the end block compresses a lot of structure to buckle. Also structure beside the end blocks are involved in this process. Buckling itself produces a kind of bending, not as it is by a moment of force acting one a structure like a beam that is loaded between to supporting walls.

It is important to have a notion on how and whre the structure in front of the end block and beside the end block hold a specific rigidness in that process. The reacting structure on the arching produceses the not being a striaght line structure that join the convex arching shape of the spehical bout shape with the concave shape of the C-bout. I have been able to show that such straight line structural condition is possible to construct by geometry, this aplayable to make. When we have acces to these specific location of structural quality we become able to contriol the behaviour of the dynamic spherical bout shape that produce accoustic result. So when you as a maker know all this you are able to control the acoustic outcome. The shape of the structural condition around the end blocks thus is an important structure to consider to shape otherwise you are not able to controll the important behavior of the dynamic. Hope this explain something to consider.

 

I suggest you start a thread about this. A couple of our members would be very interested. 

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While I have no hard evidence to refute this idea, I do believe that there can be too much vibrating area.  Otherwise there would be lots of great 15" violins.

 

When I first started making violins, I graduated out as far as possible in all directions, with the same idea that more is better.  Now I don't, and I think it's an improvement.

 

I would assume others felt that way as well when the Cremonese method was first developed....

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Hi All, In The American Heritage textbook we can read.about Acoustic and Acoutics as well as Dynamic and Dynamics.

The difference between these two are Acoustic is about sound we hear and can study the quality, frequency etc.

Dynamic is about motion and the consumption of energy, thus a continuous change of activity. So when we apply this on describing the function of the violin we must think of how to shape for a dynamical process that lead to an acoustic result. If we have the acoustic result, we can record and make frequency visible in a graph but we do not know anything about the dynamic quality, where and under what dynamic conditions the sound is produced. This is the reason why I have concentrated my study on structural design in order to find out what behavior we can expect, thus the dynamic behaviour and what we can or must change in order to optimise the behaviour and with this the resulting acoustic outcome.

All this is very complex but has learned me a lot on how to shape the arching and how to graduate of the plates and what to do to improving the dynamic function and with this the sound quality. In this process much has to be considered.

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I think Don's observation about not needing to maximize the vibrating areas is very interesting.  That might explain a lot about some of the modern violins I don't like.  I've been mumbling for years that violins are being made TOO well these days;  that would probably include trying to max out the vibrating areas.  Of course, there is no such thing as making "too well."  But "too carefully" is what I mean.

 

Leaving a lump here or there probably wouldn't kill anyone.   :)  It seems to have worked well enough for the best of the old fellows. 

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Hi All, In The American Heritage textbook we can read.about Acoustic and Acoutics as well as Dynamic and Dynamics.

The difference between these two are Acoustic is about sound we hear and can study the quality, frequency etc.

Dynamic is about motion and the consumption of energy, thus a continuous change of activity. So when we apply this on describing the function of the violin we must think of how to shape for a dynamical process that lead to an acoustic result. If we have the acoustic result, we can record and make frequency visible in a graph but we do not know anything about the dynamic quality, where and under what dynamic conditions the sound is produced. This is the reason why I have concentrated my study on structural design in order to find out what behavior we can expect, thus the dynamic behaviour and what we can or must change in order to optimise the behaviour and with this the resulting acoustic outcome.

All this is very complex but has learned me a lot on how to shape the arching and how to graduate of the plates and what to do to improving the dynamic function and with this the sound quality. In this process much has to be considered.

 

I can't say I understand much but you could start a new thread and present there your theory and your method and your results.

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Dear Carl. It's a pity that you do not understand what's written in "The American Heritage"  This makes it even more difficult to understand what it means in practise.

Before a structure becomes dynamic it is forced mechanic and change shape by the string load top pitch. That process will take at least 24 hours. There are several investigations that show how the instrument change shape and where stress is produced. Stress and frequency are related to each other. A string must have a specific stress in order to vibrate with a specific frequency. Principally we find the same circumstances on the bout SHAPEs of the violin. They must hold enormous different stress condition in different direction on order to start vibrating spontaneous by the action of the string acting on the bridge and the structure underneath. Changing the thickness graduation on the bout at a specific Place Changes the stress condition and with this the location where a specific frequency earlier started spontaneous

So what we have to consider is, Arching shape, Wood condition thickness graduation, structural deflecting and stress condition, the dynamic behaviour of all this and finally the acoustic result.

Most scientist start studying the acoustic result and hope to find out what the structure would be becoming better. I did the other way around, thus started making a structure and then study the function as described above and finally the acoustic outcome. Hope you are able to understand the consequences of all this. You may study my internet site at www.zuger.se. and find your own understanding. Not agreeing just make a not for discussion. You will find my email address.

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