Long Arch Drawing

[Don Noon]

The only direct exposure I have had with distortion and re-arching is with a golden-era Strad that was more saddle-backed than the CT scans, and re-arched to unsaddle it.  Immediately after the restoration (and several weeks thereafter) the power was significantly diminished, but slowly returned to its former glory.  There was no significant tonal difference.

As I understand the vibration theory, the center island long arch would act about the same whether flat, slightly convex, or slightly concave, as the wood stiffness dominates the acoustics in the area.  Related changes in the curve of the upper and lower bouts should be more significant... but maybe not by much.

[JacksonMaberry]

1 hour ago, Marty Kasprzyk said:

Maybe we should try to duplicate great violins a little faster.   If the famous violins we like so much have saddle shape creep deformed arches like Don's CT scans show then maybe we should make an undeformed arch to start with and then quickly creep it into the deformed shape if you don't have the patience to wait 300 years.

So I suggest putting your new violin with tensioned strings into your kitchen oven with a pan of water and then leave it until you get a Strad Titian, or DG Plowden shape or your favorite.  Sort of like sticking a fork in it to see if it's done.

 

Actually it might be fun to carve a top and then steam press it into the plowden slump just to see what happens 

[Andreas Preuss]

11 hours ago, David Burgess said:

How can one make a top "as light as possible", without pre-knowing the environmental conditions it will be exposed to over the next 10 to 300 years?

Here is how one van make it:

Working with wood which has undergone different treatments such as soaking succeeded by steaming and heating, I can positively say that many things become possible you wouldn’t dare with untreated wood. It resists by far better what you describe as ‘environmental conditions’. 

[Don Noon]

19 hours ago, David Burgess said:

How much arching distortion do you consider to be acceptable in either 10 or 300 years, and how much of a burden would you like to pass on to your customers and fiddle-trade descendants?

7 hours ago, Andreas Preuss said:

I can positively say that many things become possible you wouldn’t dare with untreated wood. It resists by far better what you describe as ‘environmental conditions’. 

There is no dividing line between "as light as possible" and "too light" regarding creep and distortion.  It's all a matter of what one considers acceptable, given the (usually unknown) conditions the instrument will see.  While a thin Strad might come with the (acceptable?) burden of re-arching every few decades, it might be less acceptable for a modern instrument.

And while my wood treatments are unlikely to be the same as Andreas', I am likewise convinced that my torrefied wood is far more resistant to environmental conditions and creep.  Objectively, the wood moisture content is reduced by 40%, and subjectively: try bending torrefied maple ribs.

 

[JacksonMaberry]

Wood treatment is a huge topic unto itself and probably beyond the scope of Dennis' original concept for this thread, but it always warrants further discussion and I'd love to talk about it with you all in a concerted way. 

One such method, if you'll forgive me, that seems interesting:

Apparently Antonio Montana ponded his wood in a saturated decoction of coca alkaloids. 

[David Burgess]

3 hours ago, JacksonMaberry said:

Wood treatment is a huge topic unto itself and probably beyond the scope of Dennis' original concept for this thread, but it always warrants further discussion and I'd love to talk about it with you all in a concerted way. 

One such method, if you'll forgive me, that seems interesting:

Apparently Antonio Montana ponded his wood in a saturated decoction of coca alkaloids. 

Saturating the wood with cocaine? Steeping the wood in a solution of "magic mushrooms", canabanoids, or LSD might work pretty well too.

[JacksonMaberry]

4 minutes ago, David Burgess said:

Saturating the wood with cocaine? Steeping the wood in a solution of "magic mushrooms", canabanoids, or LSD might work pretty well too.

Now we're talking! 

[scordatura]

I wonder if the prominent soloist (Kavakos) has had arching correction done to the 'saddled" Strad  mentioned above? Did Florian sell him the instrument? Sounds damn good. I've heard it live a few times.

[Davide Sora]

Just now, scordatura said:

I wonder if the prominent soloist (Kavakos) has had arching correction done to the 'saddled" Strad  mentioned above? Did Florian sell him the instrument? Sounds damn good. I've heard it live a few times.

Yep, Mr. Kavakos is a darn good violinist, would also make a cigar box sound like a Strad.

[Michael_Molnar]

On 3/30/2022 at 5:00 AM, David Burgess said:

General consensus among restorers seems to be when a top has become distorted that much, re-arching it (again?) will greatly improve the sound and playing properties.

 

On 3/30/2022 at 10:36 PM, Don Noon said:

The only direct exposure I have had with distortion and re-arching is with a golden-era Strad that was more saddle-backed than the CT scans, and re-arched to unsaddle it.  Immediately after the restoration (and several weeks thereafter) the power was significantly diminished, but slowly returned to its former glory.  There was no significant tonal difference.

As I understand the vibration theory, the center island long arch would act about the same whether flat, slightly convex, or slightly concave, as the wood stiffness dominates the acoustics in the area.  Related changes in the curve of the upper and lower bouts should be more significant... but maybe not by much.

OK. I’m confused. Who is right?

 

[JacksonMaberry]

On 3/31/2022 at 8:22 AM, JacksonMaberry said:

Antonio Montana

A little disappointed nobody pegged this as a Scarface joke

[reguz]

I strongly believe there is a great misunderstanding when people say

“God bless, look at how sunken that top is!” if there is any of that than please explain why the back does not show any outward deformation! Not on any of them showed. Thus the sound post must have been shortened. I do not believe in this. This is not likely.

What we see is the belly bout structures buckling outward. These instruments are 300 years old!

[JacksonMaberry]

2 minutes ago, reguz said:

I strongly believe there is a great misunderstanding when people say

“God bless, look at how sunken that top is!” if there is any of that than please explain why the back does not show any outward deformation! Not on any of them showed. Thus the sound post must have been shortened. I do not believe in this. This is not likely.

What we see is the belly bout structures buckling outward. These instruments are 300 years old!

A gut reaction like I posted is not exactly unnatural. I do take your point though, and of course the considerably weaker endgrain regions buckling outward is the key movement. Keep in mind also that due to the innate differences in spruce and maple that the latter is more resistant to deflection - of course we do see post distortion in backs, but rarely to the same degree as tops. 

Soundposts do move and are subject to the whims of those who can move them. Let's not discount to readily the possibility that length and placement choices by well intentioned tinkerers can contribute to how time and pressure exert force on thin bits of wood. 

Ultimately I agree with you, for the record. But I think you're picking a fight where none exists. I wasn't making an assessment, I was reacting from the gut to an extreme image.

[HoGo]

2 hours ago, reguz said:

I strongly believe there is a great misunderstanding when people say

“God bless, look at how sunken that top is!” if there is any of that than please explain why the back does not show any outward deformation! Not on any of them showed. Thus the sound post must have been shortened. I do not believe in this. This is not likely.

What we see is the belly bout structures buckling outward. These instruments are 300 years old!

I see that same misunderstanding from your side. movement is all relative so it's all about where you set your fixed reference point(s) in space. You can call it whatever you wish if you choose your reference points accordingly, the reality is that the arch is severely deformed.

Soundposts do get exchanged or adjusted all the time, and back won't show deformation as much as top in this view because it goes along centerline while back deforms mostly on side of soundpost and of course with much higher strength of maple back (thicker and harder wood) and direction of forces involved it will always be the top that shows largest deformations.

[Don Noon]

6 hours ago, Michael_Molnar said:

OK. I’m confused. Who is right?

Could be both.

Severe distortion can screw up fingerboard projection, string clearance, and bridge height, which are important things for playability and sound.  It seems sensible to re-arch, rather than messing with those other things to follow a sinking top.

All other things being equal (which they can't be), my single datapoint is that re-arching initially attenuated the highs, but recovered after a while to be about the same as pre-rearched, which was very good.  I'm sure there are others who have more datapoints.

[James M. Jones]

One of my first fiddles developed the hog back a few months into its life . After that , I abandoned trying to simply copy the posters and focused on a more simple arch , a relatively consistent radius without the plateau often seen on historical examples, I e noticed they still move over time , but so far not to the degree as that with the flatter area . 

[JacksonMaberry]

Just now, James M. Jones said:

One of my first fiddles developed the hog back a few months into its life . After that , I abandoned trying to simply copy the posters and focused on a more simple arch , a relatively consistent radius without the plateau often seen on historical examples, I e noticed they still move over time , but so far not to the degree as that with the flatter area . 

Out of curiosity, how thin did you go on that plate? 

[James M. Jones]

29 minutes ago, JacksonMaberry said:

Out of curiosity, how thin did you go on that plate? 

Off the top of my head …? Can’t tell ya , I can say at that point I was rather , shall we say … plateau curious… ? lol …and so had to experiment with it a bit .but only a bit , I can also say that as time progressed my grads got thinner overall and more uniform, without leaving any extra thickness  in the bridge area. And my wood got less dense. And overall the back, ribs ,blocks and lining all got thinner and lighter .Personally I attribute the hog -saddle back to an overall geometry of the top arch ,as the old sailing goes  “to flat /hog back” … ( ok I made that up)  with a more constant radius the forces are , seem to be , balanced in a way that resist deformation to a much greater degree that a flattened version, my deformed plateau was originally very slightly convex, not flat . 

[JacksonMaberry]

No worries! Im still doing sort of a plateau, but it's not dead flat. It's just a larger radius than the arcs that make up the other parts of the LA. I also leave things pretty damn thick both in between the ffs and at the soundposts, but very thin as the cross approaches the channel. It's a little odd I guess by contemporary standards, but you can see it in some good old fiddles. So far not much distortion, and no saddleback. We'll see!

[James M. Jones]

2 minutes ago, JacksonMaberry said:

No worries! Im still doing sort of a plateau, but it's not dead flat. It's just a larger radius than the arcs that make up the other parts of the LA. I also leave things pretty damn thick both in between the ffs and at the soundposts, but very thin as the cross approaches the channel. It's a little odd I guess by contemporary standards, but you can see it in some good old fiddles. So far not much distortion, and no saddleback. We'll see!

Mine wasn’t dead flat either , rather a gradual shift in radius to almost … How much time has passed on yours? And how stable is your environment? I live in Wisconsin and can /do experience several humidity cycles and temperature ranges any given week . My fallen arch  happened fairly quickly. Within a year if memory serves. Since then several changes  . I decided to thin the top to a uniform, more or less thickness with the idea that mass equals impedance, or resistance to movement , and felt like that little bridge needed as much wiggle room to have more amplitude available. Given that the top was already braced in a way by the bass bar and sound post , it doesn’t seem that extra thickness is needed if the geometry is providing support for the long arch . 

[Dennis J]

To get things in perspective the scans show top deflections of perhaps 2 mm, not much more. It would probably be quite noticeable though. And I would say that the actual depth of the instruments has not changed from their original measurement.

[JacksonMaberry]

25 minutes ago, James M. Jones said:

Mine wasn’t dead flat either , rather a gradual shift in radius to almost … How much time has passed on yours? And how stable is your environment? I live in Wisconsin and can /do experience several humidity cycles and temperature ranges any given week . My fallen arch  happened fairly quickly. Within a year if memory serves. Since then several changes  . I decided to thin the top to a uniform, more or less thickness with the idea that mass equals impedance, or resistance to movement , and felt like that little bridge needed as much wiggle room to have more amplitude available. Given that the top was already braced in a way by the bass bar and sound post , it doesn’t seem that extra thickness is needed if the geometry is providing support for the long arch . 

I only have one instrument with me, my first. It's almost 7 years old and still ok. The other one I saw most recently was made around the same time, and it's fine too. It's been all over, played by a baroque professional. Mine stays pretty consistent in climate in my shop, which I regulate carefully. 

I agree that geometry is most important, and the arch is the most critical element in general along with inherent wood properties. Grads are much less important I think. But they do do something, mostly related to color and palette, and that's my reason for obeying the pattern you see in Stainer and associated makers. 

[James M. Jones]

28 minutes ago, JacksonMaberry said:

I only have one instrument with me, my first. It's almost 7 years old and still ok. The other one I saw most recently was made around the same time, and it's fine too. It's been all over, played by a baroque professional. Mine stays pretty consistent in climate in my shop, which I regulate carefully. 

I agree that geometry is most important, and the arch is the most critical element in general along with inherent wood properties. Grads are much less important I think. But they do do something, mostly related to color and palette, and that's my reason for obeying the pattern you see in Stainer and associated makers. 

Mind you , I am Not asserting that any one way is best or anything like that. Or that I even really know anything myself , just offering personal thoughts on the subject. I’d be real curious to try a full blown plateau someday, a few of the ones I have restored had great tone. Although I suspect the long thick plateau also contributed to the cracking and spreading of the upper and lower bouts , again though ... conjecture.

[Michael_Molnar]

12 hours ago, Don Noon said:

Could be both.

Severe distortion can screw up fingerboard projection, string clearance, and bridge height, which are important things for playability and sound.  It seems sensible to re-arch, rather than messing with those other things to follow a sinking top.

All other things being equal (which they can't be), my single datapoint is that re-arching initially attenuated the highs, but recovered after a while to be about the same as pre-rearched, which was very good.  I'm sure there are others who have more datapoints.

Another question is why are the highs restored?

[reguz]

A gut reaction like I posted is not exactly unnatural. I do take your point though, and of course the considerably weaker endgrain regions buckling outward is the key movement. Keep in mind also that due to the innate differences in spruce and maple that the latter is more resistant to deflection - of course we do see post distortion in backs, but rarely to the same degree as tops. 

Soundposts do move and are subject to the whims of those who can move them. Let's not discount to readily the possibility that length and placement choices by well intentioned tinkerers can contribute to how time and pressure exert force on thin bits of wood. 

Ultimately I agree with you, for the record. But I think you're picking a fight where none exists. I wasn't making an assessment, I was reacting from the gut to an extreme image.

 

My answer on this structural deformation is.  YES also the back may show an outward bending together with the what you may say is a downward movement. Of course there is a downward load but an equal upward load act on the end blocks. Is the back thin at the soundpost location a local deformation may arise.