francoisdenis

Who do retouch thicknesses from outside ?

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1 minute ago, curious1 said:

The Medici Stradivari 1716 has a neck graft and I would assume a new bass bar that went along with the graft.

Messiah: neck graft, bass bar

Lady Blunt: neck graft, bass bar

I haven’t seen the CT scans of it but it does have a wedge added to the neck and extensive repairs to woodworm damage in the lower bout of the back.

 

Of course you're right, none is intact if you consider neck, bassbar and crack repair, as far as I know.

I just thought to thicknesses.

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3 minutes ago, Delabo said:

Could you please answer why a one to one absolute perfect bench copy of a Stradivari will not sound exactly like the one copied ?

Short answer would be The wood is different

Ex. Make two exact carbon fiber violin copies and they would sound pretty much the same.

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9 minutes ago, Delabo said:

As a newbie who has read all 576 replies in this thread and is more confused than when I started reading it.

Could you please answer why a one to one absolute perfect bench copy of a Stradivari will not sound exactly like the one copied ?

The technology is there with scanning tecniques. And one would assume the same for laser cutting or some other method that would produce a visual and actual exact copy.

If the violin does not sound the same, and putting aside supernatural magic, it could only be down to the  the wood used  for the copy ?

Right ?

 
My opinion is that copying exactly an instrument deformed by centuries of string tension does not mean copying exactly what the original author did.
By force of things it can not lead to identical results, if ever this was really possible, even having the same wood at disposal.

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6 minutes ago, Davide Sora said:
 
My opinion is that copying exactly an instrument deformed by centuries of string tension does not mean copying exactly what the original author did.
By force of things it can not lead to identical results, if ever this was really possible, even having the same wood at disposal.

Sorry Davide, somehow my post ended up in this thread but should have been in the "strad concept" thread so I have moved it. :)

But anyway...........

So time is an essential ingredient in the mixture  ?

If so, How did it sound when first made ?

Like a Strad ?

One would have to assume it to be very good considering Strads clientele and the price of his instruments ?

 

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4 minutes ago, Delabo said:

Sorry Davide, somehow my post ended up in this thread but should have been in the "strad concept" thread so I have moved it. :)

But anyway...........

So time is an essential ingredient in the mixture  ?

If so, How did it sound when first made ?

Like a Strad ?

One would have to assume it to be very good considering Strads clientele and the price of his instruments ?

 

Like a Strad of that time, that appeal players of that time, except those who still preferred Amatis and Stainer....

And of course like a baroque violin:)

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47 minutes ago, Davide Sora said:

Of course you're right, none is intact if you consider neck, bassbar and crack repair, as far as I know.

 
I just thought to thicknesses.

Unless someone can convince me otherwise, I assume everything has been regraduated to some extent. 

Because:

1 I never met a violinmaker who didn’t think he could improve a violin with either a new bass bar or taking out a little wood. At least until they decided it needed a patch because it was too thin.

2 The ideals of conservation were fairly lax in the 18th and 19th centuries, hell even a great portion of the 20th, and scraping the top to put in a new bass bar was a pretty regular practice.

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29 minutes ago, Davide Sora said:

Like a Strad of that time, that appeal players of that time, except those who still preferred Amatis and Stainer....

And of course like a baroque violin:)

Ah,  baroque music  !

I forgot about that !

That throws a spanner in the works !

My favorite classical music.

More likely to have been played on a Stainer or Amati rather than a Strad ?

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2 hours ago, Don Noon said:

No need for a funeral; its clones, brothers, and many descendants will live on forever in other shops.

It was never in my shop, as it has never made any sense from a technical/theoretical viewpoint, and I haven't seen any empirical evidence that it results in anything superior, other than telling a newbie the difference between a log, violin plate, and sheet of paper.

I too keep records.  Although my database is not very extensive, I too have the impression that crossgrain stiffness needs to be at least reasonable.  Very low longitudinal stiffness is also not good, but that's more intuitively true.  My preference is to stock wood with known good properties, and not work up a plate to get a taptone and then find out if it's good or not.

Don,

Do you think spruce wedges cut out near the edge of the trunk have a lower cross-grain stiffness than those cut out near the center? I am thinking of the enormous Sitkas that can be 5 or 6 feet in diameter., and wonder whether the curvature of the annular rings affects cross-grain stiffness. If so, smaller diameter spruces would be desirable. 

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Mike,

I don't know what might change in the cell walls to make a difference, and I haven't seen much difference from edge to edge in my wood (although I haven't really looked hard).  Geometry-wise, more curvature in the annular rings would put more tangential (and more importantly, more off-angle cut) in the crossgrain, and make it less stiff.  Theoretically.  But I don't see any reason why it wouldn't happen.

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Apart from deliberate regraduation, another major alteration you see is the thinning of the edges, from flattening the plate every time it's taken off. Often the edge was scraped to blend in the resulting wider flat area. It can be a real problem if you're trying to build it up again with a 1/2 edge. 

Of course many have been restored as best as possible.

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18 hours ago, Quadibloc said:

Now, I agree that there are flaws in the idea of graduating on the outside. I think it wasn't done in practice because it would injure the looks of the instrument. If you're objecting because it will wreck the arching, I'm not trying to say you are wrong. 

I am really anal about keeping perfect arching on my instruments. I don't understand why folks keep repeating thet nonsense... Noone is really digging a hole "here and there" in random spots of arch. Most folks who do this are taking small amounts (less than a 1/10th of mm at time ) from relatively large areas and no one would be able to notice the "missing" wood with naked eye. The archings of old instruments are so uneven and distorted (sometimes the asymmetry is in mm's) that no one can argue that taking 1/10th from outside will mess the arch. I've seen folks remove more wood during final scraping before finishing...

It's usually folks who never tried it. There's guy named James Condino who builds upright basses and mandolins and he took this to extreme by building temporary rib/neck assembly with added lining on the outside to which he screws top and back (through extra overhang) and then strings it up, he can adjust top back from any side (or trim the tonebars) and string it again and play, and he claims you can really get the tone where you want after some experience. Once the plates are "tuned" he glues them to real ribs and trims the overhang. I have no reason to doubt what he says.

I've experimented with lots of things being rational math and IT guy I loved al the tuning theories of Hutchings et al and I measured and tested chladni patterns of all various modes of plates of my instruments and whole lot of other stuff, but the one that works best for me in the workshop without too much complication is tuning of assembled instrument. Actually it is not hard at all to regraduate assembled violin or mandolin from inside (with the right tool) and reshape the tonebars or bassbar through f hole, but why bother when no one can tell if I removed some wood from outside.

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4 hours ago, Peter K-G said:

Short answer would be The wood is different

Ex. Make two exact carbon fiber violin copies and they would sound pretty much the same.

Yeah, one day some violin maker and tech freak will figure it out.

 

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On 5/6/2018 at 9:09 PM, Davide Sora said:
 

Fear..... and try to imagine what could happen.

 
How do you know when to stop, or if keep scraping can lead to further improvements or make the result worse?

Well, this is just a matter of knowing what you are doing. Of course in the process of learning you can ruin a dozen or two of violins... but that will be payed back by a huge knowledge that you get in the end. Of course I am talking about serious approach, not about mindless scraping here or sanding there.

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I use light scraping and sanding of the plates as well as ribs and even neck and pegbox in the process of final tuning of the instrument when it is strung in the white. I also use the final tuning of the ff - holes at the same stage. To me all these procedures are a must and is a stage where I can modify the sound of the instrument to be exactly what I want it to be (understanding that all the previous stages have been accomplished). It usually does not take more than removing 0.1 mm to make significant change in the sound without a risk of ruining the instrument. That took a while to learn.

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7 hours ago, Artiom said:

Well, this is just a matter of knowing what you are doing. Of course in the process of learning you can ruin a dozen or two of violins... but that will be payed back by a huge knowledge that you get in the end. Of course I am talking about serious approach, not about mindless scraping here or sanding there.

 

Wow, a rather wasteful learning system, one or two dozen violins are a few years' work for me:o

If we add the years of experimentation necessary to learn also for cellos and violas I would have to close my shop and continue as an amateur maker to find the necessary time.:D

 
Seriously, I think you can probably understand something useful in that way, maybe I'll try sooner or later on an experimental basis out of curiosity, but I'll have to equip myself with a good CNC and the collaboration of other people to shorten the time.....:rolleyes:
 
In the meantime I will have to keep making my violins, as I think Stradivari and his drinking buddies also did.
 

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Hello Francois!

I'm a great admirer of your work!

I've been developing a method for external voicing of instruments for over twenty years. I attended the Oberlin Acoustics workshop for about 12-15 years and had a close working and personal relationship with Oliver Rogers, a noted author and

respected expert on instrument acoustics. Meaning that these ideas and methods have been thoroughly vetted and are based on
 
sound
scientific principles. 

 

 

My method is based on the concept of
 'string reciprocity', meaning that there is a bi-directional relationship between the string and the corpus. The tensioned string of a setup and tuned instrument responds to the tapping of the surface with the same 'information' as contained by the bowed (and/or plucked) string.
How the instrument will sound after making changes is dependent on psychoacoustics. 

Oliver Rogers wrote an intriguing paper on this subject when he noticed that a viola he was playing sounded great in one key and bad in another. He compared the resonant frequencies of the instrument with the two keys and found that one key matched more closely while the other, inferior sounding key, was offset from the resonant frequencies. 

The same thing happens when an instrument is adjusted, a small change in a frequency 'band' can affect a large change in perception. Making random adjustments to the outside usually results in mass cancellation of effect, though a reduction in overall mass may make the instrument somewhat more responsive and louder.

 
I agree with a previous poster who noted that not only is graduation changing but changes in the arching amplify the effect. I've also noticed that the thinner the plate the greater the effect of external voicing. If the plate is too thick then external removal of wood doesn't noticeably change the sound. I believe (religiously ;-) that this may be one reason that regraduated Strads et al. can still sound wonderful because the subtle changes in the arching have not been changed with regraduation.
 

My 'evidence' for the possibility that this method may have been used by the Cremonese makers is that some makers, notably Del Gesu, left obvious tool marks on the instrument. A good example is the Del Gesu 'Il Cannone' which has toothed plane marks on the lower left bout of the back. These tool marks correspond with anomalies in the graduations.

 
The way I imagine the Cremonese implemented this method in that they were finishing the instrument from the outside already, they simply set up the instrument in the white and scraped and adjusted the instrument as needed, listening to the response of the tuned strings as they were scraping. I've done this, working mostly on my lap and find it very doable and quite natural. This model fits my criteria of Cremonese working methods in that it has to be efficient with no unnecessary steps, no wasted material or time.
 
Discussions such as this invariably inspire the 'absolutists'. No, not every Strad etc. was voiced, not every Strad sounds great. the varnish doesn't destroy the sound etc. If you start with a better sounding instrument you'll end up with a better sounding instrument, even if it isn't the exact same sound. And an occasional instrument will 'go off the rails' for one reason or another.
 
I'm also not interested in providing specific instructions or trying to convince anyone that this works. But I'll happily respond to reasonable questions.
 
Oded Kishony

 

 

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7 hours ago, Oded Kishony said:

I agree with a previous poster who noted that not only is graduation changing but changes in the arching amplify the effect. I've also noticed that the thinner the plate the greater the effect of external voicing. If the plate is too thick then external removal of wood doesn't noticeably change the sound. I believe (religiously ;-) that this may be one reason that regraduated Strads et al. can still sound wonderful because the subtle changes in the arching have not been changed with regraduation.

I wonder what change in arching you consider noticeable (sound-wise). IMO, no matter what method you use (inside first, outside first, adjusting from inside or outside) you always have to decide on basic arching scheme when you start carving, and even if you chose to leave some extra wood for final adjustments it's less than a mm (or more likely less than a 0.5mm) so even if you remove all this wood from outside the outside arch won't change more than that mm or 0.5mm. I consider that very minor change assuming that basic top arching height can vary from let's say 13mm up to 18mm depending on model. There is also the "neutral" plane of arching mentioned by more engineering types which is actually changed by roughly half of the amount removed from one side, wich makes this even less noticeable.

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9 hours ago, Davide Sora said:

Wow, a rather wasteful learning system, one or two dozen violins are a few years' work for me:o

If we add the years of experimentation necessary to learn also for cellos and violas I would have to close my shop and continue as an amateur maker to find the necessary time.:D

Davide, I've been doig this since I started building (arch top mandolins, but I did some work on trade fiddles as well) and never wasted one instrument. I spent years playing hundreds of instruments till I learned to judge the sound and playability of instruments and measured archings and thicknesses of majority of them as well to create mental picture of the general relation of thicknesses and sound (you cannot gauge densities of wood but general trends in tone are similar if you average enough instruments).

I made instruments from wood rejected by other makers as "too dense", "too soft", "too wide grain" down to "too ugly" and have been able to maneuver the sound of the instruments into succesful mandolins without too much fuss. There's always the first step of carving them close, but I feel I can dial in the sound in the final stage a bit closer to what I want.

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49 minutes ago, HoGo said:

Davide, I've been doig this since I started building (arch top mandolins, but I did some work on trade fiddles as well) and never wasted one instrument.

This sound more reasonable.....:)

I think that everyone during his career must develops an ability to manage the variables to perfect things by aiming at improving the sound, the most important thing I think is to develop the sensitivity necessary to judge the sound quality, as you rightly point out.

The method that is used to achive the results is irrelevant if you do not develop this ability, that is the hardest thing to be developed and that allows you not to waste any violin.

Indeed, even more important than that, it is essential that there is a firm intention to improve, which is not at all obvious among makers.

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2 hours ago, HoGo said:

I wonder what change in arching you consider noticeable (sound-wise). IMO, no matter what method you use (inside first, outside first, adjusting from inside or outside) you always have to decide on basic arching scheme when you start carving, and even if you chose to leave some extra wood for final adjustments it's less than a mm (or more likely less than a 0.5mm) so even if you remove all this wood from outside the outside arch won't change more than that mm or 0.5mm. I consider that very minor change assuming that basic top arching height can vary from let's say 13mm up to 18mm depending on model. There is also the "neutral" plane of arching mentioned by more engineering types which is actually changed by roughly half of the amount removed from one side, wich makes this even less noticeable.

For the first 1000Hz (+/-) it is the entire corpus moving as a whole. I've found that changing the stiffness of a section, which includes top ribs and back as a unit can often result in dramatic tonal changes.

I don't think you need to have a 'scientific' understanding of violin acoustics to make this work. The instrument has to have a final scraping, if you do it with the instrument set up and listen to the vibrating strings you are getting real-time acoustic feedback-isn't that better than doing it deaf? You don't close your eyes when you scrape the surface why shut out the sounds of the instrument? The violin has the potential to be speaking to you and describing the sound qualities of every mm of its surface. 

This reciprocity technique can also be used to analyze the instrument, to find resonant frequencies, nodal lines, potential harmonic frequencies etc. 

An anecdote: When I attended the Oberlin acoustics class I was waiting in line with Doug who was waiting to have his balsa violin tested for its spectrum profile. I tested his instrument and came up with a number for the first air mode. Nailed it! :-) It's not a substitute for FFT but it can be very handy.

Oded

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Thank you for your compliments Mr Oded,  I 'm not surprise to have not been alone probably something that not easy

to speak about..

I repeat that my concern has never been to make a Strad but only to experiment in a very modest way that suited me.

I took out the notes taken at the time of the tests. All (about twenty) were conducted on blank instruments. Some was finished (almost)
on other was only body without prufling (which changes all in the sound just as everyone knows ...) with screwed neck.
Here are the reactions of a viola table from the lower pitch.
Past an octave the patterns reproduce.
I had used the idea of Chaldi's figures, the nodal zones cross appear in dark black, the shaded areas are those where the vibration node is fuzzy, the red areas are those where the vibration is the most intense.


Obviously the operating mode was very rustic, I used a tuning fork and my ears and certainly did not play the perfect pitch, but however I found very interesting these figures visualizing in live the operation of the violin because it was possible to act directly on an area and then look at what was happening and also what was changing , or not  when you retouched the thicknesses.1225348549_vibrationtablealto.thumb.jpeg.bf2b86120e8ebbb85a7bc542a11d1b91.jpeg

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On 5/11/2018 at 8:37 AM, Oded Kishony said:

My 'evidence' for the possibility that this method may have been used by the Cremonese makers is that some makers, notably Del Gesu, left obvious tool marks on the instrument. A good example is the Del Gesu 'Il Cannone' which has toothed plane marks on the lower left bout of the back. These tool marks correspond with anomalies in the graduations.

Having made a pretty meticulous copy of the Cannon I have to say that my thoughts about those tool marks are that they came rather from very hasty work. Otherwise one can see the hasty work on the head, on the execution of the purfling and the cut of the f holes.

On 5/11/2018 at 8:37 AM, Oded Kishony said:

The way I imagine the Cremonese implemented this method in that they were finishing the instrument from the outside already, they simply set up the instrument in the white and scraped and adjusted the instrument as needed, listening to the response of the tuned strings as they were scraping. I've done this, working mostly on my lap and find it very doable and quite natural. This model fits my criteria of Cremonese working methods in that it has to be efficient with no unnecessary steps, no wasted material or time.

But this aside, the idea that Cremonese instruments have been adjusted from the outside is very well possible. The bigger question is rather, if this was done, how they did proceed and what they aimed at. Was it an overall thinning down process or did they have something like a map for adjustments knowing in which spot they could trigger certain aspects of the sound. As they didn't have modern equipment to register the sound I would rather assume this was a more or less general adjustment. Looking at the thickness distributions and variations from instrument to instrument one can somehow roughly guess how this could have been done.

Judging from the tools they used it seems to be to be reasonable to conclude that more or less uniform thickness made with the help of the thickness puncher before assembling the instrument. The graduations were thereafter obtained by reducing the thickness from the outside and if some extreme irregularities occurred they were 'corrected' by later 'restorations'.

At least it is fairly uncomplicated to scrape material on the back from the outside. But on the top with the fingerboard , the bridge and the tailpiece blocking certain areas, there was probably more preliminary work done to avoid to take down strings and bridge multiple times. In this context it is as well possible that the straight line system in the archings was used in order not to loose control.

If you have already 20 years of experience with it, what are your observations? Would this make sense?

 

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On 5/11/2018 at 7:28 PM, francoisdenis said:

Thank you for your compliments Mr Oded,  I 'm not surprise to have not been alone probably something that not easy

to speak about..

I repeat that my concern has never been to make a Strad but only to experiment in a very modest way w

On 5/7/2018 at 5:08 AM, Andreas Preuss said:

Maybe that's all we need to know? ;)

hat suited me.

I took out the notes taken at the time of the tests. All (about twenty) were conducted on blank instruments. Some was finished (almost)
on other was only body without prufling (which changes all in the sound just as everyone knows ...) with screwed neck.
Here are the reactions of a viola table from the lower pitch.
Past an octave the patterns reproduce.
I had used the idea of Chaldi's figures, the nodal zones cross appear in dark black, the shaded areas are those where the vibration node is fuzzy, the red areas are those where the vibration is the most intense.


Obviously the operating mode was very rustic, I used a tuning fork and my ears and certainly did not play the perfect pitch, but however I found very interesting these figures visualizing in live the operation of the violin because it was possible to act directly on an area and then look at what was happening and also what was changing , or not  when you retouched the thicknesses.1225348549_vibrationtablealto.thumb.jpeg.bf2b86120e8ebbb85a7bc542a11d1b91.jpeg

 

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On 5/11/2018 at 1:28 PM, francoisdenis said:

Here are the reactions of a viola table from the lower pitch.

Looks like you're working with a plate rather than a whole instrument, is this correct?  Oded Kishony  

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