Carving site recommendations for plate tuning

[Don Noon]

5 hours ago, David Beard said:

I do understand that for a copyist the frequencies can be viewed as just one more detail to copy in a specific instrument. 

2 hours ago, JacksonMaberry said:

No two violins will be the same, no matter what is done. Full stop

Just one more clarification of my viewpoint...

Undoubtedly if you carefully copy the Cannone weights and taptones (assuming you could actually get them), what you end up with will have more Cannone character than, say,  the Boothe Strad.  Does that mean it will be a good instrument?  Sound exactly like the Cannone?  I'd say no and definitely no.  Would your result be better or worse if you made the plates lighter with lower taptones?  I'd say it depends on who is doing the playing or listening.  I doubt you'd improve things by going heavier on that one, and IMO for a new instrument thinner would be acceptable to more players.

If you try to copy the Boothe Strad, you're probably on thin ice (so to speak).  The same kind of ideas apply here too, but in this case going thinner/lighter I think would be sailing off the edge of acceptable.  But if you think the character of the Boothe is exactly what you want, then maybe you could try it.  It might be too extreme, but it would certainly be closer to the Boothe character than the Cannone character.

I have a general character in mind when I start an instrument, and I do track weights and taptones (and absolute stiffness) to get somewhere close to a zone that I think does what I want.  However, I can't obsess about a few grams one way or the other, or several Hz in taptone variations.  From experience regraduating many instruments, those levels don't move the needle enough to worry about.  In reviewing my data, I think I could probably just start with the known density and stiffness of the wood, and go directly to caliper measurements without bothering with those other in-process measurements, and the result would be the same.  But they are easy measurements to make, so I do.  

 

[David Beard]

46 minutes ago, Don Noon said:

Just one more clarification of my viewpoint...

Undoubtedly if you carefully copy the Cannone weights and taptones (assuming you could actually get them), what you end up with will have more Cannone character than, say,  the Boothe Strad.  Does that mean it will be a good instrument?  Sound exactly like the Cannone?  I'd say no and definitely no.  Would your result be better or worse if you made the plates lighter with lower taptones?  I'd say it depends on who is doing the playing or listening.  I doubt you'd improve things by going heavier on that one, and IMO for a new instrument thinner would be acceptable to more players.

If you try to copy the Boothe Strad, you're probably on thin ice (so to speak).  The same kind of ideas apply here too, but in this case going thinner/lighter I think would be sailing off the edge of acceptable.  But if you think the character of the Boothe is exactly what you want, then maybe you could try it.  It might be too extreme, but it would certainly be closer to the Boothe character than the Cannone character.

I have a general character in mind when I start an instrument, and I do track weights and taptones (and absolute stiffness) to get somewhere close to a zone that I think does what I want.  However, I can't obsess about a few grams one way or the other, or several Hz in taptone variations.  From experience regraduating many instruments, those levels don't move the needle enough to worry about.  In reviewing my data, I think I could probably just start with the known density and stiffness of the wood, and go directly to caliper measurements without bothering with those other in-process measurements, and the result would be the same.  But they are easy measurements to make, so I do.  

 

I've read your posts for years.  You don't claim to get more from tap tones than is realistic.  

I fight against tap tones because as a whole modern making and marketing give an irrational level of credit and significance to the concept.

[Marty Kasprzyk]

Joseph Curtin reported some top plate mode 5 and mode 2  frequencies of nine old Italian violins in his 2006 Strad article "Tap Routine" which is attached.  Please notice that he also lists the weights of these plates one of which is the 1716 Booth Strad that Don just mentioned.

Is there any more similar data on other good violins' plates published?

Curtin's article mentioned that Carleen Hutchins suggested he should watch his plate weights back in 1986.  He wrote his article 30 years later and now after another 14 years this simple idea still doesn't seem to be catching on as important.

Tap_Routine_-_J_Curtins_Strad_article_06.pdf

[Don Noon]

2 hours ago, Marty Kasprzyk said:

He wrote his article 30 years later and now after another 14 years this simple idea still doesn't seem to be catching on as important.

If the "simple idea" produced significantly better results, it would have caught on.  And the range of plate properties is fairly wide.  Just looking at the Strad range, and comparing to 24 of my violins:

22 were within the weight range.  My first violin was heavy, and the Snakefiddle (ultra high RR experiment) was light.  That ain't a tough one.

20 were withing the M5 range.  4 had high M5 frequency.  Also not a tough one.

Only 5 were within the M2 range; all the other 19 were high*.

The 5 within the M2 range were also within the weight and M5 range, therefore the "best" numerically.  However, the blind tone competition results of those instruments didn't turn out significantly different from all of the others.  Some scored very well, others just good to middling.

By the way, my 15" viola also was within all of the Strad criteria, but I didn't put violin strings on it to compare.  Probably woulda been a cool fiddle.

These are all bare plate measurements with no bass bar or varnish; so there can be some differences, as the Strad plates had (some) varnish.  

 

*Curtin also noted the M2 difference between old and modern instruments.  It may be micro-cracking crossgrain or something like that, but it just didn't seem logical to me to contort the graduation pattern to get M2 reduced, given that the ones that DID have lower M2 didn't sound any better.

 

[Anders Buen]

7 hours ago, Don Noon said:

*Curtin also noted the M2 difference between old and modern instruments.  It may be micro-cracking crossgrain or something like that, but it just didn't seem logical to me to contort the graduation pattern to get M2 reduced, given that the ones that DID have lower M2 didn't sound any better.

 

I think he later said that removing the wide stiffer upper and lower block region parts of the plates to the sides of the blocks made the modern plate behave similar to the older ones for mode 2. This was originlly my intuition. I call these the «Sacconi plateus» but none working in his tradition has approved this name. They are there in Hutchins illustrations of plates, and I think some fine makers prefer to keep these for crack prevention, and for the stability and possibly for the sound.  

[Don Noon]

Anders, I recall Curtin mentioning that as well.  M2 is extremely sensitive to crossgrain stiffness at the endblock areas, so there are a couple of important things that would make for a difference between old and new violins, besides the "Sacconi Plateau" difference:

-New white plates don't have cutouts for necks and saddles.  These cutouts will lower M2.

-Varnish.  I have removed tops on quite a few of my violins, and the net effect of the varnish and neck/saddle cutouts has always been to raise M2 by several Hz.

-Endblock areas are prone to saddle cracks, neck cracks, and incidental cracks from removing tops for repairs.  Repairing these cracks perfectly is probably not critical for the re-assembled violin performance, but will lower M2 in the free plate.

-Hemicellulose degradation.  Crossgrain properties will be most affected (reduced), lowering M2.  Cellulose is far more stable, which will keep longitudinal stiffness from degrading.

Perhaps Curtin has tried carving around the endblocks to see if that mimics the lower M2 of old plates.  I have not tried it, and haven't spoken to him specifically about it.  If the M2 difference is from cracks, or hemicellulose degradation, it is unclear if trying to match that free plate mode in a new build makes any sense.  That's assuming you varnish the plate and make neck/saddle cutouts first, then do your mode tuning.

Seems like a hell of a lot of tedious work for no obviously better result, unless getting particular free plate modes is your ultimate goal.

[Marty Kasprzyk]

I've monitored the M5/M2 ratio while thinning the tops.  Attached is a graph of how that ratio changed as I removed wood in various places.  The "Sacconi Plateau" area is very sensitive.  Removing wood there lowers M2 while raising M5 thus raising the ratio.  

Also attached is a photo of the Titian Strad top plate which shows Stradivari didn't use a "Sacconi Plateau" like Curtin has shown for his plates.

[Don Noon]

1 hour ago, Marty Kasprzyk said:

The "Sacconi Plateau" area is very sensitive.  Removing wood there lowers M2 while raising M5 thus raising the ratio.  

The thing about M2 partucularly that bothers me is that it is SO sensitive to the crossgrain stiffness at the ends of the plate.  When the plate is glued to the ribs, all of that gets completely obliterated by the stiffness of the ribs and end blocks.  It seems to me that some of the M5 might leak through to the assembled violin, but still there is the edge constraint problem making M5 and assembled modes barely related if at all.

This idea of selectively removing wood from specific areas to tune the M2/M5 ratio seems equivalent to editing the genes of a dog to make it more like a tiger... you'll just get a disfigured dog.

[Peter K-G]

Fully agree

[Cathode Ray]

On 9/3/2020 at 3:16 AM, HoGo said:

I thought current trend is predominantly about getting good arching shape and then thickness towards optimal weight/stiffness measured whatever way the maker chose (bending in hands or taptones). Experience is the key here. After making dozen(s) of violins consistent way some relationships appear and new instruments are more consistent around desired outcome. If they don't appear then either the maker has no talent for this or he needs to change the way he works or evaluates his results.

Tap tones/tuning of plates alone sound like magic wand but they've been around for many dacades now and we still don't see everyone building great instruments tuned to the perfect pitches. There is more than just the taptones behind work of a master.

In light of the results of double blind listening studies on old vs new violins, would it not be more expeditious to look at more current arching/thickness numbers from accomplished makers?  The task at hand is after all to make good instruments with "existing" woods. They are being built and whether a result of plate tuning or intuitive flexing and feeling is irrelevant. A database of current specs would be more insightful/useful to me.
But what do I know...

[Anders Buen]

2 hours ago, Cathode Ray said:

In light of the results of double blind listening studies on old vs new violins, would it not be more expeditious to look at more current arching/thickness numbers from accomplished makers?  The task at hand is after all to make good instruments with "existing" woods. They are being built and whether a result of plate tuning or intuitive flexing and feeling is irrelevant. A database of current specs would be more insightful/useful to me.
But what do I know...

If these data were unimportant, maybe the makers would have shared them more openly?  

[Anders Buen]

One of problems with extracting information and data from violin plates and instruments is that they all are dependant on the MC of the wood, which vary with the climate daily and over the year. I think that controlling the shop humidity is an important factor for consistency in making. Having a good mid range shop RH also is good if instruments are to be shipped worldwide to any climate. 

Wooden density, youngs moduluses, loss factors (damping), size and shape all are dependent on the MC. The sound too. 

The idea of plate tuning is an attempt at reducing the complex problem of making decent to good violins to a few parameters. Some probably are a little more important than others, but the complete set is needed to make a violin. 

Correlations can be found, even in literature claiming there is none. But should these explain more than 50%? The parameters should share the 100% in a good working model. 

Players and makers do probably not agree on what is good and not. Maybe some grouping can happen. Some do agree on something. This makes a clear unified decision difficult. And do we measure the instrument quality or the test persons preferences? This theme is impossible to solve.  

I think most makers can line up the important factors for making a good violin. It is definitively more information than three to four numbers with units gram, and Hz. If one stick to the same model and wood: maybe the answer is a little easier? The % variance from these factors are smaller and the remaining variance is explained by the rest, hidden variables or not. 

[Marty Kasprzyk]

On 9/12/2020 at 11:11 AM, Don Noon said:

The thing about M2 partucularly that bothers me is that it is SO sensitive to the crossgrain stiffness at the ends of the plate.  When the plate is glued to the ribs, all of that gets completely obliterated by the stiffness of the ribs and end blocks.  It seems to me that some of the M5 might leak through to the assembled violin, but still there is the edge constraint problem making M5 and assembled modes barely related if at all.

This idea of selectively removing wood from specific areas to tune the M2/M5 ratio seems equivalent to editing the genes of a dog to make it more like a tiger... you'll just get a disfigured dog.

 

 

The M2 and M5 (and a bunch of others) and the assembled modes are indeed related as shown by Colin Gough's finite element analysis (attached) where he starts with the free plate mode frequencies and then gradually adds the stiffening of the ribs.

It is very easy to make a plate of uniform thickness with the aid of simple calipers.  But the plates of famous old Italian instruments show quite a bit of thickness non uniformity.  It is not know if this variation is due to indifferent workmanship or whether it was intentional.  Nevertheless it does affect the various plate and assembled mode frequencies and therefore the resultant sound.

 

 

Gough.pdf

[Anders Buen]

My five cents on the matter, shared many times before. https://www.researchgate.net/publication/336473862_Free_plates_and_signature_modes_of_violins_are_there_any_correlations

[David Beard]

3 hours ago, Marty Kasprzyk said:

 

 

The M2 and M5 (and a bunch of others) and the assembled modes are indeed related as shown by Colin Gough's finite element analysis (attached) where he starts with the free plate mode frequencies and then gradually adds the stiffening of the ribs.

It is very easy to make a plate of uniform thickness with the aid of simple calipers.  But the plates of famous old Italian instruments show quite a bit of thickness non uniformity.  It is not know if this variation is due to indifferent workmanship or whether it was intentional.  Nevertheless it does affect the various plate and assembled mode frequencies and therefore the resultant sound.

 

 

Gough.pdf 4.18 MB · 4 downloads

I would suggest it most likely was a conscious acceptance of the natural consequences of the limits of the tools and methods the chose to use.

In other words, if thought of it as a problem, they could have done differently, but they didn't.

If they thought of the degree of random drift their plates show was considered a neutral non-issue or an actual positive feature is a more open question.

But, they didn't take steps to avoid that drift.  We can see that.

I consider this another example of them 'repeating what works' or learn as a community by 'process evolution'.

 

Is their level of random drift in plate thickness a virtue?  I suggest it might well be.  This unevenness will I beleive tend to raise the Q of resonances in the instrument, broadening and blending their responses to driving signals.

But the old would have no need for a why.  They had a good accepted tradition that gave this result.  If they experiment with making a few plates more perfect, all they need do is consider if the like the resulting instruments better, or not.  Not appears to be their answer since they made including the drift for centuries.

[Peter K-G]

Sometimes I wonder?

Is it the common assumption, that we as human beings have evolved in 300+ years after "the old guys". There is nothing new that we know now, that they didn't know back then (in the context of wood and violin plates/acoustics).

At that time they where as intelligent as we are now (probably more). Technology has developed, but not in this field to the extent that it could make any difference. 

All great makers knock on wood, back then as now

 

[Don Noon]

1 hour ago, Peter K-G said:

Technology has developed, but not in this field to the extent that it could make any difference. 

Technology has developed to the extent that you can waste a LOT of time looking at it.

I spent a while trying to figure out the Gough plots with all those lines going from free plate modes to the body modes.  As near as I can tell, all of the free plate modes go way off the map when ribs are added, and the body modes come from somewhere else.  And it appears that the FEM is simplified to where it has no F holes, no sound post, no bass bar.  But maybe I'm wrong.

In Anders' article, yeah, there's a fairly poor correlation between plate modes and body modes, but it's there.  No biggie:  stiffer plates have a slightly higher likelihood of coming out with higher body modes.  But if you want an exact body mode, there are widely varying plate modes that can end up there.

Add to all of that:  good violins have a fairly wide range of body modes.

In the end, there is no case to be made for controlling free plate modes that I can see, although straying way outside of the "normal" range (which is pretty wide) isn't likely to do well.  Time would be better spent looking for other things, likely by trial-and-error, that might matter more... like arching and good wood and a million other details.

Nearly 30 years ago, in an article by Dunnwald comparing Old Italian, modern master, and factory-made violins, the very first conclusion was:  "All curves are similar in the lower frequency range, up to 700 Hz."  Which means the difference is not in the signature modes, but elsewhere.  It matches what I have found.

[Don Noon]

9 hours ago, Cathode Ray said:

The task at hand is after all to make good instruments with "existing" woods.

I prefer to use wood that doesn't exist.

[Marty Kasprzyk]

12 hours ago, Anders Buen said:

If these data were unimportant, maybe the makers would have shared them more openly?  

Hi Anders,

I recall reading an interview with the violin maker Peter Greiner where he mentions his close collaboration with the physicist Heinrich Duunwald.  Greiner was asked what his secret of violin success was and his answer was something like "Why should I describe what I'm doing--anybody could then make a great violin" 

 

[Anders Buen]

3 hours ago, Marty Kasprzyk said:

Hi Anders,

I recall reading an interview with the violin maker Peter Greiner where he mentions his close collaboration with the physicist Heinrich Duunwald.  Greiner was asked what his secret of violin success was and his answer was something like "Why should I describe what I'm doing--anybody could then make a great violin" 

 

Many makers do make great violins, every now and then. When somebody does a PhD and spend a lot of time doing measurements and interpretitions of those they need to come up with some results within the budget time they have available. 

In my opinion Dünnwald did a fundamental error in throwing away the overall SPL in his data. Loudness comes up as the most important factor in percepted acoustic analysis. It is a descriptor of power and distance, fundamental in perception to any animals, I think. E.g. Singing birds must have a loudness war as they are so loud for their tiny size.    

Dünnwald continued his measurements after the thesis was delivered. It may have been in collaboration with makers, for access to fine instruments, like Greiner. At that time, mid 1980, personal computers and an acoustic measurement system was something very few had access to. Possibly he put some $ and time into this. 

A system like that can tell if the acoustic properties of a violin is in the ballpark or not. Playing it will too, given enough experience with good instruments and playing capabilities.

Light top plates will statistically tend to give instruments with higher L-parameter values. All impact frequency spectra i have analyzed of modern US makers do have L >= 18 dB and most over 20 dB. Factory violins (anno 1985) in general have heavy tops and thus the L is low.   

[Anders Buen]

Regarding Dünnwalds Sound parameters I have done a few years research in trying to figure out what influences these. The level of the A0 in relation to the mid frequency response is called the L parameter. Lower top plate weights and low Mode 1 frequencies go with stronger L-values. This affects the stiffness of the box. Lower stiffness gives a stronger A0 response.

We have also seen some traits of weakening the midfrequency response from adding mass close to or at the f-hole upper wings. A typical patch and repair position. 

Furthermore higher arching and thinner border region of the back plates seem to go with higher values of the ACD-B (see Figure).

The most difficult part is the higher frequencies. DE-F, bass, bridge and setup may be crucial.

I have also seen that high values of Dünnwalds parameters does correlate with a lower overall SPL. A «Dünnwaldian» violin may have a certain sound characeristics but may not carry as well. D´Addarios old Naepolitan violin is an example of that, sweet sound but not particularly powerful. (If you attend the VSA Oberlin Violin Acoustics Workshop you will probaly hear or even play it).

However some violins have both Have high scores of DW parameters and high SPL. An example is the de Diable del Gesu on the Miracle makers, at least it is like that in the recording.

Later research have shown that the nomenclature used by DW for «nasailty» etc was not well founded. Also the frequency regions for different classifications are disputed. But to be honest, I have not been able to understand the contant of this, not from reading it nor from hearing the presentations. I am not going to do the work over. 

I do think that good violins can have a strong mid frequency response, e.g. Boosting the fundamentals of one or some notes on the E-string. The winner of the VSA 2016 competition was one such instrument. Strong E string instruments are fun to play. How do we measure «fun factor»? Or just let it be?

Edited September 20, 2020 by Anders Buen
Added figure and corrected spelling errors

[Don Noon]

14 hours ago, Anders Buen said:

Furthermore higher arching and thinner border region of the back plates seem to go with higher values of the ACD-B (see Figure)....

I do think that good violins can have a strong mid frequency response, e.g. Boosting the fundamentals of one or some notes on the E-string. 

I have also noticed that higher arching tends to suppress the "B" frequency range, giving a more "old Italian" tone but less overall power.  I haven't gotten to the point where I can assign the effect to the top or back plate, though.

I agree that good violins don't necessarily have to have a low B frequency band, although I primarily like the strong overtones and punch it gives to the G and D string, and don't really like the offensive power and unevenness that usually shows up on the E string.  I know Curtin thinks that the "old Italian sound" character is not necessarily preferred these days  The real problem is excessive peaks in the B range, which are not that easy to control.

Anyway, thanks, Anders, for all this incredibly detailed real-world work, which I find far more useful that just theory.

[Advocatus Diaboli]

I’m always a little surprised by the focus on the fundamental frequency of the free plate modes.  The best sounding Italian instruments that I’ve handled taken apart had pretty distinctive qualities to the tone of the free plate modes and stuff like that. Kind of a complex thud and less like a clear tone.  The less amazing sounding ones don’t as often have the same quality. 

[Peter K-G]

We must be all in great need to repeat ourselves

 

For the record I'll repeat:

If you want them (M5/B1) to correlate it's possible up to R^2 1.0.

(Anders will say that there is something wrong if R^2 1.0 and I will say  My data and Wikipedia says that it's possible)

 

 

[Marty Kasprzyk]

8 hours ago, Advocatus Diaboli said:

I’m always a little surprised by the focus on the fundamental frequency of the free plate modes.  The best sounding Italian instruments that I’ve handled taken apart had pretty distinctive qualities to the tone of the free plate modes and stuff like that. Kind of a complex thud and less like a clear tone.  The less amazing sounding ones don’t as often have the same quality. 

Others have also mentioned the "thud" sound of old plates.  I interpret this to mean that they have highly damped wood.  

It can be shown that high damping reduces the transient time for establishing a steady string vibration during the start of a bowed note.  I'm guessing this might make for more articulate playing and help make music with fast passages sound more clear.

High damping also shortens the sustain time after the bowing stoops (plucked guitars too) so this also might be helpful for playing fast passages.  On the other hand some people like the carry-over ringing from one note into the next.  They describe this as a "carillon bell tower effect" that produces a chord.  This might be the "resonance" effect some people use as a descriptor.