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Tap tone test , top plate


Arsalan
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Precise and perfect apply much more directly to a 'good gun' or 'good toaster' than to a 'good violin'.

A violin is not a engineering or manufactor or quality control product so much as an artful skilled craft.

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This discussion got me curious, because the maker I worked with tried all that stuff years ago, but doesn't pay much attention to it now, preferring to flex his plates and judge by feel. I happen to have an exceptional sounding violin open for a crack repair in my shop downstairs at the moment. It's ready to reassemble, so I went down and tapped it every way I know how, trying to leave it free to resonate freely. I held the plate in all the prescribed ways I am aware of, tapped with fingertip and alternatively the end of  a piece of sound post, and was rewarded mostly with a dull "thunk", and hardly any resonance at all. Yet this violin, before I opened it, with a cracked top and sound post in an "unusual" location was outstanding in comparison with the best of the 200 or so I have on hand. Not the best of the best perhaps, but would certainly hold its own with the better ones. I don't think resonance and great sound necessarily go together.

 

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There can be no argument against wood properties being important at some level, otherwise we might see fine-sounding violins with maple or rosewood tops.  The lightness and stiffness of spruce matters.  There can also be no question that the maker matters too, as the same names surface at the top of tone competitions or professional players' preferences.  The question is how much the finer details of the wood properties matter, once you get in the range of "good tonewood"... whatever that is, and whether more "goodness" in the properties is actually better.

Generally, density and longitudinal speed of sound are the primary properties that makers might measure (or at least get some feel about them by tapping a billet); some also listen for the "ring", or a feel for damping.  Sometimes crossgrain speed of sound might be measured, but not often.  That still leaves about twice as many unmeasured properties, and who knows if they are important or not.

Tap tones of a carved plate I think can be very misleading, for several reasons.  The main one is that the vibration modes of the free plate are vastly different from how they vibrate in the assembled instrument.  Free plates mostly flap at the edges, and the frequencies are only up to a few hundred Hz.  The critical range in violins is generally 1500 - 4000 Hz, and might have very different "ring" compared to the free plate taptones.  Or something.  It's complicated, and I don't have real answers.  Yet.

 

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21 hours ago, Michael Richwine said:

This discussion got me curious, because the maker I worked with tried all that stuff years ago, but doesn't pay much attention to it now, preferring to flex his plates and judge by feel. I happen to have an exceptional sounding violin open for a crack repair in my shop downstairs at the moment. It's ready to reassemble, so I went down and tapped it every way I know how, trying to leave it free to resonate freely. I held the plate in all the prescribed ways I am aware of, tapped with fingertip and alternatively the end of  a piece of sound post, and was rewarded mostly with a dull "thunk", and hardly any resonance at all. Yet this violin, before I opened it, with a cracked top and sound post in an "unusual" location was outstanding in comparison with the best of the 200 or so I have on hand. Not the best of the best perhaps, but would certainly hold its own with the better ones. I don't think resonance and great sound necessarily go together.

 

The traditional  method of flexing the plates by hand is a good way of sensing plate stiffness and with a lot of experience one can get a "feel" for shaping his plates and making their instruments sound good.

One issue with this technique is that it is difficult to transfer this proper "feel" to others far away. This is either good or bad depending upon your view point.  If you are an established maker trying to protect your business it's good that your experience can't be easily passed on to competitors.  So when you die your knowledge also dies.  Later on, another maker can with lot of trial and error experience can develop the same skill and feel and the cycle is repeated.  This is called a "saw tooth" learning curve where the same ability is slowly gained and then suddenly lost over and over again.  

So the advice of "Make a few hundred violins and you'll get a feel for it" follows this old tradition.  This good for young beginning makers but at my age I don't have much time left for this approach.

 

 

 

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Probably most makers would go for the wood with the higher pitch, either by instinct or by some scientific parameters. 
i would also hammer on the end grain and I think this tells more about the quality than tipping on the side. 
 

 I wouldn’t rely on acoustic testing alone. Visual criteria such as the color of the winter rings, tilt of the year rings within the log and runout are important as well.

Last not least, I prefer to buy wood only as split logs to see how twisted the surface is. In ancient times shipbuilders used only wood with little or no twist for the masts of ships because they knew it is stronger than twisted wood. 


In general, the closer the wood (especially the top) gets to its final shape the more the wood properties become ‘visible’. So if the wood is still in the form of a wedge, the picture is very blurred. It’s the skill of a luthier to ‘guide’ the sculpturing process of the plate to its best possible performance. In this process arching height is a major aspect. I believe that arching can counterbalance to a certain degree somehow weaker wood.

 

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4 hours ago, Marty Kasprzyk said:

The traditional  method of flexing the plates by hand is a good way of sensing plate stiffness and with a lot of experience one can get a "feel" for shaping his plates and making their instruments sound good.

This might be problemmatic for makers who don't crank them out at a high rate.  How can you remember what "that really good one" flexed like if you made it a year or two ago?

5 hours ago, Marty Kasprzyk said:

This is called a "saw tooth" learning curve...

Yeah, that's what would happen if I tried to go by hand-flexing and feel... which is why I prefer to use measured things and be able to look them up later.  It's still an accumulation of experience to sort out what matters and what doesn't.  Most of it doesn't.

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Paulonia is a wonderful wood and makes wonderful stringed instruments. It does not sound like spruce. So it makes a very nice violin like instrument, but it does not quite produce what we expect and like from a violin. Materials matter. The truth is that the best violins sound a lot like the best violins. We have expectations for what they are supposed to sound like. So far picking for the least dampening and fastest speed of sound on a section of spruce with tight rings, seems to give us the best of what we expect from a violin.

My ear is not perfect, but I have heard carbon fiber violins that sounded, to me, as good as the best spruce. This bothers me, I don't like it at all, but I am not going to ignore what my ears, faulty and limited as they are, tell me.

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2 hours ago, charliemaine said:

That's a nice round up of the approaches that allow an engineering personality to feel like they're doing something.

The basic problem remains.  There is no demonstration that any of those targets in a free plate relate to a good resulting violin.

Violin making isn't a science. It is an art/craft.   

You can't even formulate the problem mathematically.   A good violin is a violin that pleases a good player.  The main way a good violin is made is through the experienced hands of a good maker.

Both in the making and in the evaluation of the product, it's all inescapably about human artistic expertise.

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8 hours ago, David Beard said:

The basic problem remains.  There is no demonstration that any of those targets in a free plate relate to a good resulting violin.

The other basic problem that remains is that you can't demonstrate if a violin is good or not... which is subjective.

I have been recording thicknesses, weight, taptones, and bending stiffness, in addition to the density, stiffness, and damping of the initial wedge for about 30 instruments that I've made, in addition to a bunch of clunker regrads.  My conclusions:

  1. Thicker, heavier, stiffer instruments play/feel differently from thinner, lighter, less stiff ones, and usually sound a bit different too.  Some might like one type, some the other.
  2. Extremes in wood properties of stiffness/density will restrict where you can end up in the spectrum of thickness and weight, and will play/sound differently.  Again a matter of preference.
  3. Damping... in the wood and the varnish... seems to matter.  Also a matter of preference.

For the kind of violins that I want to make, I have found that a combination of thickness and weight is the most useful... mostly weight, but with denser wood will go a shade thinner and heavier, and the opposite for lower density.  All of those other measurements are pretty pointless IMO, although if there is something very unusual I might take it into account when settling on a weight/thickness stopping point.  Also if a client has a preference for a particular type of playing characteristic.

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3 hours ago, Don Noon said:

The other basic problem that remains is that you can't demonstrate if a violin is good or not... which is subjective.

I have been recording thicknesses, weight, taptones, and bending stiffness, in addition to the density, stiffness, and damping of the initial wedge for about 30 instruments that I've made, in addition to a bunch of clunker regrads.  My conclusions:

  1. Thicker, heavier, stiffer instruments play/feel differently from thinner, lighter, less stiff ones, and usually sound a bit different too.  Some might like one type, some the other.
  2. Extremes in wood properties of stiffness/density will restrict where you can end up in the spectrum of thickness and weight, and will play/sound differently.  Again a matter of preference.
  3. Damping... in the wood and the varnish... seems to matter.  Also a matter of preference.

For the kind of violins that I want to make, I have found that a combination of thickness and weight is the most useful... mostly weight, but with denser wood will go a shade thinner and heavier, and the opposite for lower density.  All of those other measurements are pretty pointless IMO, although if there is something very unusual I might take it into account when settling on a weight/thickness stopping point.  Also if a client has a preference for a particular type of playing characteristic.

I agree.  Very appreciate that your scientific drive has taken you to a subjective artist like description of the reality.

I think perhaps that the most meaningful understanding if the quality of a violin is an understanding of the sorts of players that will like the instrument, and maybe the range of expressive playing the instrument supports.

None of this helps those who want a measurable simplicity to hang onto.    Instead, it all revolves around very intimate expertise and experience.

 

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6 hours ago, Don Noon said:

The other basic problem that remains is that you can't demonstrate if a violin is good or not... which is subjective.

I have been recording thicknesses, weight, taptones, and bending stiffness, in addition to the density, stiffness, and damping of the initial wedge for about 30 instruments that I've made, in addition to a bunch of clunker regrads.  My conclusions:

  1. Thicker, heavier, stiffer instruments play/feel differently from thinner, lighter, less stiff ones, and usually sound a bit different too.  Some might like one type, some the other.
  2. Extremes in wood properties of stiffness/density will restrict where you can end up in the spectrum of thickness and weight, and will play/sound differently.  Again a matter of preference.
  3. Damping... in the wood and the varnish... seems to matter.  Also a matter of preference.

For the kind of violins that I want to make, I have found that a combination of thickness and weight is the most useful... mostly weight, but with denser wood will go a shade thinner and heavier, and the opposite for lower density.  All of those other measurements are pretty pointless IMO, although if there is something very unusual I might take it into account when settling on a weight/thickness stopping point.  Also if a client has a preference for a particular type of playing characteristic.

Is speed of sound in the spruce of lesser importance than 1 2 and 3?

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7 hours ago, sospiri said:

Is speed of sound in the spruce of lesser importance than 1 2 and 3?

Probably.  Decent spruce kindof comes in within a relatively narrow range.  If it is an outlier, you might need to adjust weight/thickness, or maybe avoid a piece that's very low stiffness.  Opinions only.

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On 5/19/2022 at 9:29 PM, David Beard said:

That's a nice round up of the approaches that allow an engineering personality to feel like they're doing something.

The basic problem remains.  There is no demonstration that any of those targets in a free plate relate to a good resulting violin.

Violin making isn't a science. It is an art/craft.   

You can't even formulate the problem mathematically.   A good violin is a violin that pleases a good player.  The main way a good violin is made is through the experienced hands of a good maker.

Both in the making and in the evaluation of the product, it's all inescapably about human artistic expertise.

Well said, and that is what I hope Arsalan takes away from the article. 

My favorite one from the article...

7. What do you do if you're not a control freak?

Just make your top plates to weigh about 65g with the bass bar and forget about all this stuff. Twist and bend the plates to get a feel of their stiffness and to impress onlookers that you know what you're doing.

"Don't worry-be happy" or "Keep calm and carry on"

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1 hour ago, charliemaine said:

Well said, and that is what I hope Arsalan takes away from the article. 

My favorite one from the article...

7. What do you do if you're not a control freak?

Just make your top plates to weigh about 65g with the bass bar and forget about all this stuff. Twist and bend the plates to get a feel of their stiffness and to impress onlookers that you know what you're doing.

"Don't worry-be happy" or "Keep calm and carry on"

It's fun the writer included that.  But in context, the article makes that seem like a secondary or inferior approach.

In truth, dead reckoning by experience is the only thing that yields good violins.   Even when an individual maker uses one of the 'scientific techniques', that is only a false mask.  It is the component of them also dead reckoning by experience/intuition that actually gets the job done.

 

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1 hour ago, charliemaine said:

Just make your top plates to weigh about 65g with the bass bar and forget about all this stuff.

Yeah, pretty much.  You still have to get the arching right, and start with decent wood.

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On 5/18/2022 at 8:00 AM, Don Noon said:

Mostly I think it's getting the basic arching and graduations in a good zone, with good workmanship.  Dense wood will want to be thinner than lighter wood, although there is some debate about whether the arching should be adjusted as well.  I keep the same arching, and just vary the thickness.

Ok thank you very much for your reply, I also notice , it seems the fluting can increase the quality of sound . And also seems it’s not a bad idea of have the arching start right after the fluting closer to edge , by this I mean , consider two plate with same arch height at the Center line of the plate ... if you fill up the plate with for example water ... the plate that contain more water , seems to create better sound quality... I hope I could explain it well ... the plate that can contain more water ( with the same height at the Center line ) seems to vibrate better ... 

I use Stradivarius moles from graniluthai... with a little modification... 

I would appreciate if you could also tell me where do you recommend to get the woods from .... 

thanks again 

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On 5/19/2022 at 8:58 AM, Andreas Preuss said:

Probably most makers would go for the wood with the higher pitch, either by instinct or by some scientific parameters. 
i would also hammer on the end grain and I think this tells more about the quality than tipping on the side. 
 

 I wouldn’t rely on acoustic testing alone. Visual criteria such as the color of the winter rings, tilt of the year rings within the log and runout are important as well.

Last not least, I prefer to buy wood only as split logs to see how twisted the surface is. In ancient times shipbuilders used only wood with little or no twist for the masts of ships because they knew it is stronger than twisted wood. 


In general, the closer the wood (especially the top) gets to its final shape the more the wood properties become ‘visible’. So if the wood is still in the form of a wedge, the picture is very blurred. It’s the skill of a luthier to ‘guide’ the sculpturing process of the plate to its best possible performance. In this process arching height is a major aspect. I believe that arching can counterbalance to a certain degree somehow weaker wood.

 

Thank you very much for your information... would you plesss tell me what do you mean by twisted surface... I can’t get it ... thanks again 

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Twisted.....you really don't want wood made from this historic fort stockade. The grain at the center is straight, becoming more and more twisted as the tree grows. Thus it's impossible to find a piece without runnout somewhere, depending on the split, because the wood is constantly changing through the piece.

twisty2.jpg

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1 hour ago, Arsalan said:

Ok thank you very much for your reply, I also notice , it seems the fluting can increase the quality of sound . And also seems it’s not a bad idea of have the arching start right after the fluting closer to edge....

I would appreciate if you could also tell me where do you recommend to get the woods from .... 

Don't invest too much in your arm-waving ideas about what might increase the "quality of the sound".  It probably won't do what you expect, particularly if it deviates too much from known good examples.  Violin sound is notoriously resistant to these kinds of ideas (having tried out many of them myself).

There are many places to get good wood.  Bachmann, Riviolta, Tonewood of Switzerland, and others.  I have wood from those suppliers, as well as a local US supplier of Engelmann spruce.

Re: twist... sometimes you'll have a small amount of twist to deal with, unless you want to throw out wood.  Best to match the grain direction at the centerline and have the runout at the edges of the bouts.  Otherwise, you'll get an obvious "harlequin" effect right at the centerline.  It's also harder to carve and scrape if the grain runs out in different directions at the centerline.  Best to have no runout anywhere, but sometimes you have to deal with it.

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Being an engineer by profession, I started with a quantitative bent toward violin making.

There are a few first order principles (<65g, not too thin in a couple critical areas, etc.) that make a huge difference.  Past that, the nuances of each individual piece of wood become significant factors and experience is essential for assessing and responding to those nuances.

One thing I had to let go of is the notion that wood or plates should "ring".  Indeed, violins are not bells!

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I think of the violin as a speaker cone: start with at least the idea that minimal ring in the tonal range it's meant for means that it can communicate vibrations without a bias. I think a lot of the best violins work that way. If everything comes through, then the player can pick and choose what he wants to accent rather than having that predetermined by the maker. That is the specific reason I am against tuning and personally find specifically tuned instruments boring, and in my own work have looked for ways to untune things to get this predetermination out. It's the same problem as looking for the "Strad sound". There is no such thing; the beautiful thing about those great violins is that they can become whatever the player is able to draw out of them. The limitation is then the player, not the violin. Many players are not able to shoulder that responsibility, thus the popularity of "simple" violins that sound only one version of good no matter how you approach them (and I have had makers brag about this aspect of their violins to me--any kid can make A good sound.)

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