Jump to content
Maestronet Forums

Recommended Posts

Posted

Maybe you're right. The person whose opinions I trust most likes strength around the edges, so I go with that.

I'm think'in that a strong edge would lead to more inplane movenent of the top and back resulting in greater amplitude???

Oded, wolf... I was told the wolf's den is in the area of the lower bouts ...... Right next to,on the east west axis, the lower block My thickness is 3mm and down to 2.4-5 at the 3 o'clock and 9 o'clock positions about 2.5 cm in from the edge... any thoughts?

Posted
Right next to,on the east west axis, the lower block

Yes, you've got it right. Which is the point I'm making, this region is very active acoustically and should not be dismissed off handedly.

Oded

Posted

Yes, Oh Jonesviolin, there is another plateau, a plateau of which you and most ordinary mortals are quite unaware, this plateau can be reached only through years of practice and self-denial or really good weed.

Or - some button-like cactus...

Posted

Carlos...Is that you ....Carlos? perhaps just a Dog..

In an interesting aside (for another forum) - I went to see him lecture in the early 70's when I was taking an extension course in anthropology at UCLA, and he never showed, the rat!.

Their excuse was that he was called off to Mexico unexpectedly.

Always in character.

Ok, back to the plateau...

Posted

So could "CT Castaneda" or someone else tell us whether Stradivari and his contemporaries used a "Sacconi Plateau?? On both plates?

Stay Tuned.

Mike

I have always wondered about these questions too.

I don't know why, but that "plateau" has always been sort of a tenuous proposition. Did Strad or any of his contemporaries ever even use them?

I have never worked on one, and I don't believe I have ever seen a photo attributed to him or any of the other golden period instruments using one either. Did the idea actually originate with Sacconi?

It's amazing to me how much I really don't know about the subject.

Posted

I have seen one Strad that still had it intact on the top. It's not as sharply defined as in Sacconi's drawing. I believe that many of them may have been removed by well-intended "restorers" thinking that the sound would improve. That particular instrument was so clean that the Sacconi-sighted thumbnail mark for locating f-holes was visible in the middle of the underedge of the c-bout, also.

I don't know if it was on the back. I sort of doubt it, since there wouldn't be any logic for it there at all.

Posted

I have always wondered about these questions too.

I don't know why, but that "plateau" has always been sort of a tenuous proposition. Did Strad or any of his contemporaries ever even use them?

I have never worked on one, and I don't believe I have ever seen a photo attributed to him or any of the other golden period instruments using one either. Did the idea actually originate with Sacconi?

It's amazing to me how much I really don't know about the subject.

If you look closely at the elevation lines it seems that they stop short just at the 'Sacconi Plateaus'. I think this is the Betts by the way.

Figure-5.jpeg

Posted

We made a habit for a while at B&F of measuring the thickness right at the edge of the platforms of the instruments we saw. That point should be the thickest spot in that neighborhood (excluding the edge) and on Cremonese instruments it was consistently thinner than other types, by a mm or more, often. When I (later) started making instruments, I got very conscious of not starting the rise of the arch too quickly at the ends, as you see from so many other schools, but you can't make the scoop come down lowest right at the edge of the platform, either--that ends up looking too lean, and weak at a vulnerable spot. I'm always fighting, though, to keep it from getting too thick there, and will change the arch slightly to accomodate that.

Posted

We made a habit for a while at B&F of measuring the thickness right at the edge of the platforms of the instruments we saw. That point should be the thickest spot in that neighborhood (excluding the edge) and on Cremonese instruments it was consistently thinner than other types, by a mm or more, often. When I (later) started making instruments, I got very conscious of not starting the rise of the arch too quickly at the ends, as you see from so many other schools, but you can't make the scoop come down lowest right at the edge of the platform, either--that ends up looking too lean, and weak at a vulnerable spot. I'm always fighting, though, to keep it from getting too thick there, and will change the arch slightly to accomodate that.

And now you really confused me...

Posted

If you look closely at the elevation lines it seems that they stop short just at the 'Sacconi Plateaus'. I think this is the Betts by the way.

Figure-5.jpeg

I wonder if that wide neck block influence the stability of the neck somewhat sideways. Maybe it will have an acoustic effect too?

Posted

I wonder if that wide neck block influence the stability of the neck somewhat sideways. Maybe it will have an acoustic effect too?

Interesting. If it affected any mode, my guess would be B0 somewhere closer to 300Hz. I know it's non-radiating though, and I haven't really done any studies of B0. Just a hunch.

Thoughts?

Posted

If you look closely at the elevation lines it seems that they stop short just at the 'Sacconi Plateaus'. I think this is the Betts by the way.

Figure-5.jpeg

Fasinating ... really, I can see how the wide neck block could greatly stablize the neck in the side to side motion, as Anders points out.

So revealing my ignorance again... Chad,... the relative BO hz would rise.. yes?

Posted

Fasinating ... really, I can see how the wide neck block could greatly stablize the neck in the side to side motion, as Anders points out.

So revealing my ignorance again... Chad,... the relative BO hz would rise.. yes?

Well, let's break it down rather than just throw out a straight answer that I'm still not sure on.

The edge of the fingerboard during B0 rocks upwards on a sharp angle, and the torso of the entire body wriggles up and down. The neck at the tip of the scroll pushes upward directly, as well. This combined motion of the neck and the body pivoting on a smaller point would cause a greater degree of potential torsional flex and instability between all moving parts pivoting on this central axis. Against a wider, flatter point these parts would be more likely to move up and down rather than bending and twisting across this point.

This could be important in A0-B0 matching, since the A0 mode as a breating operation is highly torsional. Could it be that in an extreme case, this would cause a thinning and diminishment of the carrying power of the Helmholtz? Completely unsure.

The following animation is a Strad belly (not sure which) moving at A0.

titian-Bk-274.30hzAni.gif

This is all speculative, of course. I have no data to support any of this. Maybe Anders can help with that.

For more information on the operation of B0 and A0-B0 matching, see Jim Woodhouse's article [link].

Posted

I guess experiments are needed to answer the question of how or if the wide upper block area affect modes and playing properties. It could rise the B0 as Chad suggest, but I do not believe in A0 B0 matching, as it in most cases will make the A0 weaker. The wide plateu and block might push the modes up a bit in their frequencies.

The possible higher stability around the upper block might make the instrument sturdier in the neck body connection and thus stay better in tune. Some of my hardangers have had problems with that. I do not use the "Sacconi plateu" nor that wide upper block, but maybe it is a good idea? My experience is that narrow block will increase the rick for failures and open seams close to the block.

Grandpa used to strengthen the end block regions in the top plates when he regraduated instruments. Sam Z also write in his article on "the Gluey" experiments that Wendy Moes and he liked the fiddle a little better with stiffneres near the upper block.

I have also heard Sam Z say that Strads do tend to have such plateus, if I do remember correctly. There are many makers and restorers here that could comment on the issue with own direct experiences.

Posted

I have never ever seen it used in any historical instrument of any school, only in new instruments where I think to myself, Ah ha, this bloke has been reading Sacconi

Just curious,

Are these new instruments are what is so called, modern Italians?

Thanks for information.

Posted

Well, let's break it down rather than just throw out a straight answer that I'm still not sure on.

The edge of the fingerboard during B0 rocks upwards on a sharp angle, and the torso of the entire body wriggles up and down. The neck at the tip of the scroll pushes upward directly, as well. This combined motion of the neck and the body pivoting on a smaller point would cause a greater degree of potential torsional flex and instability between all moving parts pivoting on this central axis. Against a wider, flatter point these parts would be more likely to move up and down rather than bending and twisting across this point.

This could be important in A0-B0 matching, since the A0 mode as a breating operation is highly torsional. Could it be that in an extreme case, this would cause a thinning and diminishment of the carrying power of the Helmholtz? Completely unsure.

The following animation is a Strad belly (not sure which) moving at A0.

titian-Bk-274.30hzAni.gif

This is all speculative, of course. I have no data to support any of this. Maybe Anders can help with that.

For more information on the operation of B0 and A0-B0 matching, see Jim Woodhouse's article [link].

Does that wobbly jello stuff actually tell you anything?

Posted

Does that wobbly jello stuff actually tell you anything?

How should I approach this question? Do you want me to explain the importance of modal analysis in the study of violin acoustics or defend it? Or do you just want me to explain the A0 mode? Or do you want me to explain the visualization of the A0 mode and how it translates to real-world analysis?

I have a rule: I do not defend scientific thought and the purpose of analytical thinking to those who don't believe in its value, because you will never convince those people otherwise.

So, what are you actually looking for?

Posted

I have a rule: I do not defend scientific thought and the purpose of analytical thinking to those who don't believe in its value, because you will never convince those people otherwise.

Careful, Chad. John is a deep scientist. Did you miss his reference to wanting to own the Feynman books.

Posted

Careful, Chad. John is a deep scientist. Did you miss his reference to wanting to own the Feynman books.

I'm not familiar with everyone on the board. You can understand how his question can be perceived as dismissive of the purpose of modal analysis and acoustic research.

The "wobbly jello stuff" tells us what movements the top makes during the A0 mode, which is helpful in visualizing what structural differences will impact what areas of the belly. In this case, the torsional movement at the top and bottom of the top aids in telling us what will happen during a shift of the size of the endblocks.

Posted

I'm not familiar with everyone on the board. You can understand how his question can be perceived as dismissive of the purpose of modal analysis and acoustic research.

The "wobbly jello stuff" tells us what movements the top makes during the A0 mode, which is helpful in visualizing what structural differences will impact what areas of the belly. In this case, the torsional movement at the top and bottom of the top aids in telling us what will happen during a shift of the size of the endblocks.

It's an idiotic caricature.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...