Violin Forum/Message Board

[John Cadd]

I have just seen a Kenmore violins article about violin,viola and cello weights. The introduction tells us that data taken in things like voting etc can boil down into fairly accurate results even though it might seem too random . The Kenmore tactic is to avoid instruments that are too light or too heavy . They warn against drawing conclusions from too little data .But even though they have a long list of different makers there are no more than two or three instruments from each single maker . But that may work along with their theory . For violins from the Gagliano family the labels are often missing .Maybe they were pinched to upgrade another instrument. But the weights table shows they stayed within good weight limits . Allesandro Gagliano was known to make experiments rather than copy exactly from any other instruments that came his way. That note is from an old Strad magazine .It said the position , length and angle of the sound holes had a marked effect on the tone quality . Good information to put into print occasionally .Variation in tone rather than standardisation is not always a bad thing . If the sound holes position makes so much difference are they acting as a sample collector . Are the standing waves inside a violin the thing to explore ? Maybe tiny moveable microphones inside the instruments will answer that .

[John Cadd]

Mr Darnton I am glad you wrote your previous post. It acted as a catalyst . Thinking of 300 year old technology and improvisation has given me a way to make violin plates . I made a cutting gauge once with a rubber wheel that had a cutting (scratching ) blade for the inside surfaces .That had a limit because you have to set the thickness of the cut first. It`s quicker than the standard thickness gauge as it combines measurement and cutting marks together.
But a much simpler idea is possible to achieve a taper from the bridge area . Eliminating the wheel for early makers I mentally replaced that with a leather slider .The drawback would be marks on the outer plate surface . Then I pictured a thin leather sheet to protect the wood. That would be too hard to control . Finally I imagined a leather strap .But this time a "Tapered " leather strap . So a marker or scratcher or spike working on the internal surface and the strap beneath protecting the surface and allowing the slider to rub on the strap while the thickness would be adjusted by the tapered leather .Just fixing the ends of the strap with a few nails would reduce the dexterity needed . The marker could be pivoted from the side .If you have a large family of sons to help it would work quite well . One to hold the plate and the other to control the top and bottom parts of the marking compass. The marking could be done with spikes . I was picturing an Iron Maiden used in torture chambers . See if you could draw a model of that . Pulling or pivotting gives a choice . If the plate and tapered strap are clamped in place , the makers two hands can be employed to use a metal U shape with a cutter limited to one thickness . The top of the U shape would have a fixed ring where the cutter could wind into a stop position .The hand beneath would check the strap position while the cutter hand would do the work .
The description here evolves as you read each sentence . So allow for that .That was the train of thoughts you set off with your catalyst post above .
The Tapered leather belt should be substantial enough at the thinnest end to last a long time. More than one belt for different areas is not a difficult restriction . Wood ,leather ,metal U shapes and spikes . All materials available at the time .

[John Cadd]

If you look at the pictures of tools used by Stradivari you see a large wooden frame with an adjustable spike opposite a white rod .The frame has a hinge on one side and a handle at the other .In use (on a single instrument ) this would probably not have been adjusted although there is an adjuster fitted on the spike . The white rod opposite , pressing on a violin plate would have made dents which would have been noticed by now (surely). But in between the rod and plates there Could have been some tapered substance /object to save all the constant adjustments .That would leave the spiking frame set at one thickness all the time . Before this frame was used the plate could have trimmed down to one overall thickness first , and then tapered to final dimensions with the spiking frame . Pressing the spike through the central sections of spruce would have been much too arduous and slow ,causing lots of damage opposite the spike . A thick leather strap would cushion the pressure from the white rod but would be flexible enough for the job .Variations of thickness might come from the elasticity of the leather . or free play from the hinge or even flexing of the wooden arms of the frame .

[Michael Darnton]

http://darntonviolins.com/tag/graduation/
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[John Cadd]

If we assume Stradivari only had two hands the handle to press the spike down takes care of one hand. The other hand holds the plate and then the white rod comes into play . The idea of a strap has it`s limitations so if I was Strad I would have something like a thimble to fit over the rod which holds a firm but padded (leather ?) surface in place with a number to show the thickness needed . If the different thicknesses were made as a set ,sometimes they might get mixed up and produce tiny very thin spots in the plates . That has been shown in some of his instruments .
But how many makers Do Not use such a spiking clamp and then profess to use the Stradivari method of making ?

[John Cadd]

I`m trying to sort out the difference between strategy and tactics ,To shape the violin plates after the outer surface is completed you need to thin the whole plate .The strategy eventually is to achieve a tapered shape from centre to edge. The tactics part is to work out the best way to do that . One way is to get the whole surface down to an even thickness first. it will be thicker than the final shape .
A better way is to make the surface taper from the centre to begin with and then work from that position . Too much symmetry is bad for sound projection on account of interference, but there must be a "best" version of tapering to make the most of the energy going into the top plate. So what kind of taper shape is best ? The idea of a tapered leather strap (thicker in the centre and thinner at the edges ) might give us a lead into a best solution .Leather may not be the only material that will keep it`s shape and be flexible without damaging the outer surface . By using the tapered strap the marking or spiking tool would be kept at the same setting . Plastic is a good material to shape in a taper .Not too stiff but flexible and not as liable to be affected by humidity . If in doubt , just say no . Normal rules apply .

[Michael Darnton]

I think you're making a very common beginner's mistake here: assuming that this job can better be accomplished by some kind of complex tooling. There's a LOT of history in this direction, and most violin makers eventually come around to understanding that the most brutal kind of hand work with the least accessory tooling will get this job done the fastest.

That is, grab a gouge and go. This is faster than pantograph routers, than CNC machines. The reason is that humans can switch instantly to whatever mode is required at the moment to get the job done. That need switches back and forth constantly throughout the process and for humans the range of tools--the size of the bite we can take, various gouges, planes, and scrapers available--is much larger, as well.

You even develop a feel for what's happening with graduations. Resetting the punch is easier than you think, too--you missed the fact that Stradivari's own tool has a large wingnut handle on top of the punch to move the point. This is very quick, punching everywhere that gets one dimension, a quick turn, then the next dimension and so on around the violin quickly, rather than messing with accessory straps, caps, etc.

Plus, once you learn it, it's fun to do it.

I imagine the problem is very similar to the problem of developing self-driving cars when a person is so perfectly suited to the job.
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[John Cadd]

Your answers give a great practical perspective on making . I hope these thoughts get into your book . It`s hard to avoid asking a related question while I`m here . Why did the italian makers leave the final outline until the plates were glued on ? I bet I read that somewhere and it`s all an urban myth .

[Michael Darnton]

That's an interesting question. I'm not sure they all did. There are some small peculiarities about Stradivari production that point to that for him, but those don't generalize to other makers.

However, what I suspect was going on in the Strad shop was that they had a division of labor situation where one person would work on one task for a while, build up a stock of pieces, then move on to something else. With apparently only one mold per model, the obvious solution is to make ribsets, take them off the mold and store them for later. They would keep their shape pretty well, but not perfectly, so each violin would be slightly different (which they are) and that difference would be finalized after the nearly-finished top was glued on for the last time. Then on to perfecting the overhang, following with purlfling to follow that violin's unique outline and then finishing the edgework.

I think the pins being uniquely under the purfling for Strads points to the Stradivari shop as being the only one definitely making in this manner. The other shops could have been doing it or not--we really can't tell.
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[John Cadd]

Several theories are gathered in redundant ,dusty piles throughout violin history but the interference which reduces radiation has still not been completely buried so far. Have you been able to nail that one down ? If I keep the question vague enough it may unearth something interesting .

[Michael Darnton]

The only research that I'm aware of that might relate to your question looks at the problem that when one part of the violin is flapping + another part is usually flapping -. if these two are of equal size and facing the same direction the radiated waves can cancel each other, resulting in the potential of 0 radiation of that note (or harmonic). Facing in different directions, being of unequal size, moving different amounts, etc, are additional factors.

This has been made visible by modern high speed laser technology used to map movements of the whole violin. Here http://hansjohannsson.com/rapidweaver%20export/rapidweaver%20export/ac.html is a discussion of some of that, and halfway down are some cool moving computer simulation images taken from this type of research.

I think the general hope of makers is that this can be used to make the violin do specific designed things, for instance, to do something to encourage movements considered desirable and suppress movements (and radiation) considered undesirable. As you can see farther down the page, as the frequencies examined move higher and higher, where a lot of tonal characteristics are defined, the system breaks into smaller and smaller pieces that are presently considered harder and harder to control.

If I were to guess a difference between this and what you are interested, your idea is concerned with initial propagation, which would happen at the beginning impact of the note. Since the violin makes a note not primarily by impact (like a guitar or piano) but through constant energy input from the bow, I think the physics are somewhat more like the page I linked to. Your idea might have more to do with the note's attack, which is also important.

That's only speculation, however, since I just follow this stuff out of the corner of my eye, not by immersion.
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[John Cadd]

I like the thought of impact which is part of playing a violin . I rarely notice something my teacher mentioned once. He said a better start to the note can be made if the bow is silently placed on the string first and then begin the note while the bow is already pressing. Lots of players crash onto the note with a bow already moving , but that is much more common .

[John Cadd]

There was one maker who tested any Italian violins he came across and worked out that isolated plate areas has specific notes and relationships to each other .Area Tuning was the name . That would fit if you wanted to reduce cancellation . Have you ever tried to see if these old violins do what he said ? There is no need to take an instrument apart or take samples . Make a list and chart for all the orchestra violins across the road .

[Michael Darnton]

No, I have always tried to view the problem with a c1700 vintage mind, not a modern one.
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[John Cadd]

There are a few ways to look at Area Tuning . One is choosing set frequencies (or relative frequencies). The second way is to just make sure that the "chosen " areas should just be tuned apart to reduce cancellation and not bother what the areas are tuned to .Just as long as they are different .Just avoid too much symmetry . Then travelling back on our time machine we can ask Stradivarius if he knows anything about cancellation . Don`t say anything if he says "No". Would Leonardo da Vinci have thought of cancellation if he had made violins ? How hard would it be to visualise such things if we had not gone to school ?
Have all the makers in the world refused to test the idea ? All except the one who wrote about it. There is so much disagreement about almost everything the chances are slim that nobody has given it a go . If you insist on doing it the 300 year old way which we can`t reliably discover you have locked yourself in a box and thrown the key away . So now we have to study Houdini instead . If Time Travel was possible it would be here already .