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Control of interference by Strad and Guarneri
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John Cadd
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PostPosted: Fri Jul 31, 2009 6:13 pm    Post subject: Control of interference by Strad and Guarneri Reply with quote

A few years ago the Strad magazine showed thickness maps of the very best instruments by Strad and Guarneri.
After enlarging the maps and trying to make sense of them I noticed two distinct approaches by these makers.
The Strads seemed to favour a thinner area left and right with a thicker area separating them.
The Del Gesus went for two thicker areas left and right with a thinner area separating.
If you think of a wave moving through wood meeting a thicker area at a slight angle to the wave it will start to deflect as if it were approaching a shallow beach.Remember on a seashore the wave will end up moving parrallel to the beach. [[ As if the thicker wood had attracted the wave. ]]
Turn that round so that the wave now approaches a thinner area at a slight angle to the wave. [[This would seem to repel the wave . ]]
Both these concepts could have been in the minds of makers of that era.
If you apply these ideas to their violins the Strad is using a crossover (a thick centre)to deflect the wave into the opposite area
and as it crosses it weakens and instead of interfering it enriches the strong wave on the opposite side. (Giving strong plus weak vibrations) This works in both directions and produces a lot of richness in the tone.
The Del Gesu method has a pair of thicker areas and between them is a thin zone which tends to deflect the waves up towards the scroll .This will also reduce interference and give a more powerful focussed sound .The centre thinner area will give maybe a boost in volume.
None of this seems to be too unscientific and if anyone has closeup experience of repairing or playing both of these maker`s instruments---Now`s your chance. Don`t forget ------------------------you read it here first.
One major obstacle to seeing this can be explained by the way many charts showing thicknesses are blank in the centre where the tailpieces and fingerboards obscured the view.


Last edited by John Cadd on Mon May 07, 2012 9:53 am; edited 1 time in total
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Janito
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PostPosted: Fri Jul 31, 2009 6:56 pm    Post subject: Reply with quote

Interesting.

Is this thesis based on simulation or speculation?
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John Cadd
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PostPosted: Sat Aug 01, 2009 5:39 pm    Post subject: control of interference by strad and guarneri Reply with quote

Janito ,I am puzzled by your rather antiseptic question.I never thought of it as a thesis.Lets see -------speculation first.
After looking at the maps for some time I left it to my subconscious to chew it over.Once the grain of the idea arose it seemed to organise itself.The idea took some time to form properly.At the back of this was a question of how much scientific knowledge would makers of that era have at their disposal?How much observation of ripples on water would lead them into similar thinking.I presumed they saw a connection between ripples and vibrations in wood.They both knew a bridge had two feet.Both feet created waves(only guessing here.
I personally don`t know how much a wave actually diverts as it moves through a violin body.I`m looking at possibilities mainly.
I realise that a wave in a violin belly has a sort of long oval shape which is the starting point.I found it simpler to look at this in a Big Bang way.What happens to the two waves that start in that split second after a bow begins to move. Where do they clash How does the bass bar affect the waves.
I have been known to ask a good question occasionally.I am 66 now and when I was 14 I asked the Geography teacher if the American Land mass had once been joined to Europe and Africa as in a jigsaw puzzle.His answer was "Oh John! Don`t be so STUPID>
The idea of waves being diverted was reinforced when I read a Physics text book to check if what I was thinking was on the right lines.So I had already worked it out for myself.Now then .I`m not a violin making genius so I assumed somebody like Stradivarius could have done what I had just done.
That`s the bulk of the background and does not include simulation at all .
One of the Strad maps had me wondering.It was as close as you could get to a hole without being a hole .But Strad ,we all know ,didn`t just churn out violins .We can be quite sure he always had a purpose.

Ever since that I`ve trusted my own instincts.
Since conjuring up these ideas I thought it would be interesting to see what reaction it would produce.
I`m finding this difficult as Richard Pryor is on tv and distracting me.
I shall look up the date of the Strad as many may not have seen these pictures.
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John Cadd
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PostPosted: Sat Aug 01, 2009 5:46 pm    Post subject: Control of interference by Strad and Guarneri Reply with quote

One of the sentences got misplaced above
After STUPID should read Ever since then-------instincts. In case it looks disjointed.
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Michael Darnton
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PostPosted: Sat Aug 01, 2009 7:34 pm    Post subject: Reply with quote

Anything is possible, but I suspect you'd come to different conclusions if you saw more charts and had a better idea of the history of graduations.
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Janito
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PostPosted: Sat Aug 01, 2009 10:22 pm    Post subject: Reply with quote

Amezcua

My comment was not meant to be antiseptic, but inquisitive.

There are some pretty fancy analyses of violin body movement that are now appearing, so I wondered whether your thesis (a position or proposition that a person advances and offers to maintain by argument) was based on these data (in which case it would be a dissertation embodying results of original research and especially substantiating a specific view).

ps - I am fascinated by the apparent reverse graduations of the tops of some del Gesus. In any case, I would listen to Mr Darnton, rather than any ramblings from me.
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John Cadd
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PostPosted: Sun Aug 02, 2009 6:41 pm    Post subject: control of interference by Strad and Guarneri Reply with quote

Here are the STRAD magazine dates for the thickness maps.
Strad diagrams are in DEC 2002.
Guarneri diagrams are in SEPT 2005.
Back copies can be ordered
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John Cadd
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PostPosted: Sun Aug 02, 2009 7:18 pm    Post subject: control of interference by Strad and Guarneri Reply with quote

Thanks Janito I have tried to keep the question open to all comers rather than anything formal.Your approach seems more the University method ,more rigorous but more likely to result in a verbal wrestling match.
For Michael Darnton ,Would the history of graduations give any better indicators of a better way to make a violin than these diagrams?
It would be a pity to shut down discussion so soon on a very interesting subject.
Two other questions ---Was the work of these makers following a scientific principle or was it a combination of evolution ( within their carreers )and intelligent design?Was their "version" of science much more informal and intuitive?
Whatever the other theories say I find it fascinating that two almost contradictory methods can both be so successful.
One of the maps for a Guadagnini seemed to combine both methods .Top half like a Strad and bottom half Del Gesu.
Sorry to be so informal.
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John Cadd
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PostPosted: Mon Aug 03, 2009 9:06 am    Post subject: control of interference by Strad and Guarneri Reply with quote

If any new makers are reading this topic you should not worry too much about whether you have a theory to make you famous but definitely get your hands on these thickness maps.There is a short reference to Sacconi which although low key is allowing the novice maker to ask WHY WAS ALL THIS INFORMATION LEFT OUT OF YOUR BOOK MR SACCONI?
The thicknesses( on their own) work for those particular instruments but I would stick to the methods of tuning the plates while building in these sorts of variations.The encouraging feature of the maps is that we do not have to slavishly follow just one perfect design.Look on the thickness maps as one more ingredient in the mixture.
Certainly it is a refreshing change from the old refrain about "the secret is in the varnish".
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Michael Darnton
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PostPosted: Mon Aug 03, 2009 12:13 pm    Post subject: Reply with quote

The problem with using just one or two charts is that it misses changes that makers made over time (and they definitely did), and also one or two instanceS don't really give you a picture of what a maker is doing, since things are much more all over the map than you can realize from such a small view. Also, you have to know it you're looking at a regraduated violin, which many del Gesus are.

With more history, and more charts, you can start to build an idea of the changes and mental process those makers went through in developing their graduations over times.
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violinarius
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PostPosted: Mon Aug 03, 2009 1:04 pm    Post subject: Reply with quote

Since Stradivari made hundreds of instruments, a theory should be based on as many examples as possible, so this link might help you.

http://kenmoreviolins.com/book.htm

"Sixty violins, violas, and cellos by Antonio Stradivari, encompassing 64 years of his working life (1670-1734)." - from link above

"Forty-three instruments by five Guarneri family members, including 24 working concert violins by Guarneri del Gesu." - from above link


http://kenmoreviolins.com/Abstract.htm

Some further reading:

http://kenmoreviolins.com/publications.htm

The Strad September 2005 "Path Through The Woods"

http://www.bormanviolins.com/articles/StradArticle.pdf

Violin graduation software:

http://www.hanspluhar.com/violingraduation.html
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John Cadd
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PostPosted: Mon Aug 03, 2009 5:25 pm    Post subject: control of interference Reply with quote

Thankyou all for such valuable material.The colour charts are exactly what I referred to.
However they include instruments from the makers` Golden Periods and surely if all the previous years work is brought in there is a dilution of the "best" examples. I doubt if these famous examples have been doctored.How strange it would be if that were the case. I am conscious that many new makers in vast countries like America can leave isolated individuals with little to guide them.
I can never understand how a country like America has no library system as we have in England.
Getting this close to such valuable examples will maybe help produce not hundreds but maybe a handful of worthwhile examples.
As to theories --a grand word for a quite simple idea .As a vibration moves through wood it loses energy.A vibration emerging from that thick wood is weaker than a vibration that would have caused interference.Even if the direction of the wave is unchanged there is a definite chance that the resulting combination will sound richer.The waves travelling in the opposite direction cannot possibly be modified in an identical way so there is even more enrichment. The bass bar effect on this can be a red herring as I heard of a violin where the bassbar got stuck by mistake to the wrong side but it played just as well.
Below is a feeling I have had before we started this discussion so bear with me.
[ The more high tech the equipment used the further we move from the thought processes that originally created these masterpieces.]
Another feeling I have (based on the general behaviour of human beings ) is that many makers "in the know" will fight tooth and nail to keep most of this secret.How depressing to be so cynical.
But full credit to the contributors so far.
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violinarius
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PostPosted: Tue Aug 04, 2009 4:02 am    Post subject: Re: control of interference Reply with quote

amezcua wrote:
Thankyou all for such valuable material.The colour charts are exactly what I referred to.

[ The more high tech the equipment used the further we move from the thought processes that originally created these masterpieces.]

Another feeling I have (based on the general behaviour of human beings ) is that many makers "in the know" will fight tooth and nail to keep most of this secret.How depressing to be so cynical.
But full credit to the contributors so far.


You are Welcome.

Voici encore:

http://www.fiddleheadstrings.com/fiddleheadstrings_web_mar06_008.htm

Problem is this Stradivari violin has a thin center, so it fits your Guarneri pattern, but it still is a nice diagram.

The reason the 'secret' is so well kept is because Antonio is making violins in heaven now. Wink
So most keep what they think is a 'secret' but in fact it is only a 'secret' to them.

High Tech is catching up quick, it is just that it has been slow getting out of the gates. How do you think you got all these nicely coloured graduation charts? Low Tech?

http://www.strad3d.org/

While the Americans have no libraries, remember they did invent the paragraph, and perfected English. Wink
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John Cadd
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PostPosted: Tue Aug 04, 2009 9:10 am    Post subject: control of interference Reply with quote

Thankyou for the maps of the Harrison violin .Such a sublimely beautiful image.
Glad you don`t mind me joshing you about libraries.We are in the middle of Test Match cricket against Australia and I always relish the friendly bating the Aussies give us.
As you talk about ideas going through your mind sometimes another answer pops up on it`s own. Today I put together the puzzle between Strad and Del Gesu. Before that ---I have noticed that the division between the two is not 100%.
What I think happens when waves hit thicker layers OR thinner layers is the speed of the wave is altered enough for the PHASE of the vibration to be slightly shifted.This seems to explain why both methods produce good results.
We are all familiar with the good old sine wave.Nice smooth curves.
Any disturbance to this will help to make a more complex vibration.That word "complex" has been used a lot to describe violin strings qualities.
Most guitar makers believe that the top of the instrument is most important and this is similar to my attitude (currently).
The video of the violin belly soundholes reminds me to ask: Is the spacing of the tops and bottoms of the holes related to the width of the bouts? To force the idea out of it`s hiding place .how would it sound if you cut the holes upside down.-----I`m starting to sound like Del Gesu every minute. ( If you have some spare firewood knocking about.) Would an intuitive feeling by the makers lead them to feel that the sound would spread-out more evenly.
They may have relied on intuition more than we realise.Any success would then reinforce that aspect of the design.
Henry Ford used to say with new engine models "OK Let`s crank it up and see why it won`t work"---20th century thinking!
Seeing the plate wobbles in the video makes me question whether these ideas are facing in exactly the same direction.The sound may be varied in more ways than appears there.I feel as if there is a question trying to get out ,...........but I have to pin it down first.
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John Cadd
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PostPosted: Tue Aug 04, 2009 10:58 am    Post subject: control of interference Reply with quote

To add on to the last post.The effect of putting a wave out of phase as it passes into a thicker area is dependant on the gradual difference in thickness between the central belly areas.This "may" explain (careful now) why some later Strad models are more robust.I am not absolutely sure they mean thicker when they say robust.Maybe that`s just around the edges.
It may mean that a sudden abrupt increase in thickness will kill the sound stone dead.Perfectly even thickness will give interference .Whereas just a little more or a little less thickness will be sufficient to create a phase shift enough to enrich the tone. (Who said Goldilocks ?)
The exact thickness would not be as important.Given an idea like that I would do exactly what Strad did and start making everything a bit stronger and more durable.As long as you fitted all that in with tuning the plates relative to each other and getting the air resonance correct the results should be outstanding.
Looking at the maps again I shall be especially interested in the thickness gradients in the direction the waves are moving(always away from the bridge feet.)
Notice one of the Kreisler Del Gesu 1730 instruments gives a very wide area for the bassbar side vibrations before a large thinner zone runs down towards the edge.
In the Betts Strad a very similar pattern --a large thinner patch slanting down to the edge.As close as these two makers came it seems.
The Alard --large thin centre area.( Del Gesu )
The Cannon --large thick centre area. (Del Gesu )
None of these divisions needs to be restricted to the centre line.(Apparently)---(Just covering myself there.)
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