Dampening agents....

[Nick Allen]

Hey y'all,

I've been pondering lately, just if there are any materials or additives that may be known or used specifically for plate dampening? 

I've observed (personally) that some of the best sounding violins that, when I've tapped the free plates during repairs, tend to make more of a thud, rather than a ring. 

It feels to me that there is something in the wood, or on the wood, or is intrinsic to the wood that is causing some kind of desirable effect that results in superb sound. 

I've noticed as well, that a lot of great sounding fiddles have a sort of percussive sound to their plucked open G string that doesn't seem to be overly resonant or full of unnecessary overtones. The result seems to be a sound that is exactly what it needs to be, free of flyaways and fluff. Basically, the core of the sound is strong, with very little interruptions from the marginal overtones. 

Has anyone here experimented with adding or processing plates in order to dampen them at specific frequency bands? 

Any input would be greatly appreciated. 

 

[Don Noon]

Linseed oil and oil varnish add damping, which smooths out the distinctive harsh, fuzzy sound of an unvarnished violin.  I think it's mostly attenuating the highest frequencies.  I have experimented a bit with this, with the conclusion that a minimal thickness of varnish is good, and more is too much.

I have not done much in the way of repairs, and have no personal experience with thuddy plates from superior violins.  I would hesitate to attribute the thuddy taptones to any kind of beneficial damping that can be added in some way.  There could be other things going on that would make for a non-ringy free plate.  Micro-cracking at the edges, hemicellulose degradation that would affect the crossgrain stiffness, or free plate mode energy transfer from the taptone to some other twisting or flapping mode.

For the thuddy plates of good violins, I'd want to know things like... new or old?  normal taptone frequencies?  unusual relationship between taptone frequencies?  how much varnish is there?  antiqued?  

[Nick Allen]

1 hour ago, Don Noon said:

Linseed oil and oil varnish add damping, which smooths out the distinctive harsh, fuzzy sound of an unvarnished violin.  I think it's mostly attenuating the highest frequencies.  I have experimented a bit with this, with the conclusion that a minimal thickness of varnish is good, and more is too much.

I have not done much in the way of repairs, and have no personal experience with thuddy plates from superior violins.  I would hesitate to attribute the thuddy taptones to any kind of beneficial damping that can be added in some way.  There could be other things going on that would make for a non-ringy free plate.  Micro-cracking at the edges, hemicellulose degradation that would affect the crossgrain stiffness, or free plate mode energy transfer from the taptone to some other twisting or flapping mode.

For the thuddy plates of good violins, I'd want to know things like... new or old?  normal taptone frequencies?  unusual relationship between taptone frequencies?  how much varnish is there?  antiqued?  

Yeah. There could be so much going on. 

But I've noticed it in both new and old instruments. But more in old instruments. 

I think that a ringy plate is usually not indicative of good sound, and have observed that.  

[Don Noon]

1 hour ago, Nick Allen said:

I think that a ringy plate is usually not indicative of good sound, and have observed that.  

It seems to me that thicker plates tend to ring more than thinner ones, at least for top plates.  I'd guess that thinner plates would have the free plate mode shapes messed up more by the bass bar than if the plate was thicker.

These are just vaguely recalled things, and could be wrong.  I have even less recollection about top plates without a bass bar.

[Andreas Preuss]

The only thing I could add here is that the top of my experimental violin came at the end to the point of having literally no tap tone but I could make it work most satisfactory. The top was at that stage below average thicknesses but definitely needed a very strong bass bar where the x shape of the bar and other adjustments helped. 
 

 

[Dr. Mark]

Nitric acid.  Although I have only on example, I would bet that any rotted out and/or decayed plate would tend to 'thud'.

[Don Noon]

Fire.  You will never get any taptone out of a pile of ashes.

[Michael Darnton]

@Nick Allen I know exactly the sound you mean. It's exciting to thump the strings on a new setup and hear this. Though these points don't address the wood issue, I've noticed that violins with round, higher arching in the center and the same type of arch carried out into be bouts can show this more often. Also, post pressure appears to be able to bring it out a bit. But of course there are violins that just have it, without those features.

I've heard the dead plate thing on good old violins many times, but I do think that this contributes more to other features rather than that punch characteristic. But I guess it could play a part. I don't think it's the deadness, per se, that does it. . .  more like that it's an allied characteristic.

[Deo Lawson]

Linseed oil and oil based varnishes will introduce noticeable damping to a plate. In a thin layer, this will give you a pleasantly warm and controlled sound.

The trade-off is pleasant sound under the ear versus being heard from far away. A little bit goes a long way and you should be careful not to overdo it, because once you load the plate with sludge you can't get it out again.

 

Obviously there are other factors which have been mentioned above.

[David Burgess]

I haven't noticed that dull-thump sounding plates produce better sound. While there are some Strads like that, I've spent nearly endless amounts of time trying to get these instrument to live up to their "Strad-sound" reputation.

There are Strads which are more easily sold to collectors, than to professional players.

Linseed oil can eventually get quite hard and brittle, so it might not be the ideal damping agent, unless the hardening of the linseed oil happens at about the same rate as the degradation of the wood.

[Victor Roman]

2 hours ago, David Burgess said:

While there are some Strads like that, I've spent nearly endless amounts of time trying to get these instrument to live up to their "Strad-sound" reputation.

I always thought that there is nothing really that "ultimately special" about Strads but the fact the best experts work on them and adjust / "tune" them to their utmost best. Add to that that we are listening to Strads being played by the best players. 

By the way, that is just my opinion, I do not expect anybody on MN to agree with me. But I hope young players will start giving more of a chance to new violins and leave antiques where they belong : the museums.

[Andreas Preuss]

2 hours ago, Victor Roman said:

I always thought that there is nothing really that "ultimately special" about Strads but the fact the best experts work on them and adjust / "tune" them to their utmost best. Add to that that we are listening to Strads being played by the best players. 

By the way, that is just my opinion, I do not expect anybody on MN to agree with me. But I hope young players will start giving more of a chance to new violins and leave antiques where they belong : the museums.

 

Regardless it seems that the history of those famed fiddles seems to defend 6 digit price tags. Or as a famous player put it: ‘My violin has seen Beethoven!’

[Andreas Preuss]

5 hours ago, David Burgess said:

Linseed oil can eventually get quite hard and brittle

?

Then all old master paintings which were made with linseed oil media couldn’t be rolled up.

[Deo Lawson]

I tread carefully questioning the great Mr. Burgess but I don't know if that is entirely accurate. At least compared to hard resins such as shellac.

[Andreas Preuss]

2 hours ago, Deo Lawson said:

I tread carefully questioning the great Mr. Burgess but I don't know if that is entirely accurate. At least compared to hard resins such as shellac.

Well, I have dried linseed oil several times and alone it forms a rubber like mass. 
 
In connection with resins this is a different story.

The only oil which seems to become ‘glass hard’ is Chinese tung oil but I don’t know how ‘glass hard’ it is because I never worked with it.

[David Burgess]

4 hours ago, Andreas Preuss said:

Then all old master paintings which were made with linseed oil media couldn’t be rolled up.

Rolling up one of these paintings is not something I would do or recommend.

2 minutes ago, Andreas Preuss said:

Well, I have dried linseed oil several times and alone it forms a rubber like mass.

Yes, that is what it does, at first.

[Dr. Mark]

6 hours ago, Victor Roman said:

I always thought that there is nothing really that "ultimately special" about Strads

I wrote a fairly long reply before I realized there's nothing to be said.

[Claudius]

4 hours ago, Andreas Preuss said:

Well, I have dried linseed oil several times and alone it forms a rubber like mass. 

the dried linseed oil becomes brittle and dark in a relatively short time, but things change when you add a resin in a so called "varnish", this is a completely different business (there are important original instruments out there showing  beautiful varnishes after centuries). And when you are using just a good linseed oil with pigments, it's another business again, as we can see in the world of the old and modern pictorial tradition.

But my problem now is that in this topic I'm reading something new about the classic violins: there are no more 'Stradivari secrets', after more than 300 years, finally few living luthiers are making better instruments (copying their Strad moulds from The Strad posters?).

But my experience is different: I have been going to concert halls for 50 years because I'm a music lover above all, and I listened to thousands of stringed instruments, and yes: the Guarneris and the Strads rule, but the Guadagnini, the Bergonzis, the Stainers, the Amatis, rule for their tone properties. In these last years I'm loving the Francesco Ruggieri violin played by Francesca Dego, it sounds better than the Ansaldo Poggi violins to my ears, but it's not because Poggi was a bad violinmaker, simply he followed different methods to achieve his tone.

Back to the topic: a very old belly compared to a new one has a different tone when you knock it with your knuckles, and it's much less permeable to the light, it has nothing to do with the varnishes because many old instruments are almost "peeled".

[Davide Sora]

14 hours ago, David Burgess said:

I haven't noticed that dull-thump sounding plates produce better sound. While there are some Strads like that, I've spent nearly endless amounts of time trying to get these instrument to live up to their "Strad-sound" reputation.

There are Strads which are more easily sold to collectors, than to professional players.

Linseed oil can eventually get quite hard and brittle, so it might not be the ideal damping agent, unless the hardening of the linseed oil happens at about the same rate as the degradation of the wood.

 

7 hours ago, Deo Lawson said:

I tread carefully questioning the great Mr. Burgess but I don't know if that is entirely accurate. At least compared to hard resins such as shellac.

 

5 hours ago, Andreas Preuss said:

Well, I have dried linseed oil several times and alone it forms a rubber like mass.
In connection with resins this is a different story.

 

5 hours ago, David Burgess said:

Yes, that is what it does, at first.

I agree with Mr. Burgess and support what he says about linseed oil and oil varnishes, which can be very soft in the early years and become hard and brittle over time. Yes, even linseed oil alone, if applied and left to age in very thin layers. Of course, the phenomenon will be accentuated by the presence of hard resins.

I don't think that too elastic a varnish is good for the sound, just as it would not be a good idea to try to make plates with a high damping ('thud'). Maybe a little bit would be okay, who knows, but how can you know how much, predict the effects in the finished violin, and keep the situation under control?

[Claudius]

26 minutes ago, Davide Sora said:

agree with Mr. Burgess and support what he says about linseed oil and oil varnishes, which can be very soft in the early years and become hard and brittle over time.

This is due to the quality of the oil varnish, not to the linseed oil itself.

[David Burgess]

2 hours ago, Claudio Rampini said:

This is due to the quality of the oil varnish, not to the linseed oil itself.

Have you not done accelerated aging tests? These can be quite an eye-opener!

Have you not noticed the differences between the older, highly-experienced accounts of how Stradivari's varnish behaves, and the way it behaves today?

[Claudius]

12 minutes ago, David Burgess said:

Have you not done accelerated aging tests? These can be quite an eye-opener!

Have you not noticed the differences between the older accounts of how Stradivari's varnish behaves, and the way it behaves today?

I don't have a professional lab where I can do accelerate aging tests, but I'm using my windows at home to do it, it's not the same thing but after few decades I thinks that my samples are aged enough. My tests on the glasses and on the instruments show no brittling or similar problems, but a new fragile varnish will become a fragile one in the future, this is one of the qualities of the varnish I mean.

Regarding the original instruments, Stradivari made very different varnishes in his career, not all of the same quality. But what you can judge as "brittle"? an original instrument who has experienced floodings, wars and fires in 300 and more years, has a brittle or a ruined/peeled/scratched varnish? Also, the siccative agents and how the varnish was prepared and applied is important, a brittle varnish at the beginning will be brittler in the future.

A Nicolò Amati violin made in the year 1654 (IIRC), ex Peterlongo, has a beautiful soft varnish, that someone here badly polished leaving horrible tracks on the back surface. It isn't brittle at all, and it's original I think. The varnish you can see in the attached photo on the il Toscano 1690 is harder compared to the Amatis varnishes, it could be brittler today than the old times, but it's magnificent.

In the other attached photo you can see a Madonna con il bambino made by a friend when I was studying the Cennino Cennini's book more than 30 years ago, I was experimenting the "vernice liquida" starting from the paintings. The varnish was made with colophony and linseed oil 1:1 and I applied it on the painting following the Cennini's guidelines (although Cennini was talking about "ancone" and not canvas). Today this my old varnish on the painting is perfect as the first day, but I don't know what will happens between 200 years.

The varnishes I made following 1500 and 1600 recipes give us extraordinarily durable varnishes, not the same thing with the varnishes made in the IX cent.

 

[David Burgess]

19 minutes ago, Claudio Rampini said:

I don't have a professional lab where I can do accelerate aging tests...

There are commercial labs which will perform such tests on samples you send them.

[Claudius]

4 minutes ago, David Burgess said:

There are commercial labs which will perform such tests on samples you send them.

It's a forced aging, it's not the same thing of the natural aging. I think that all kind of varnishes will be destroyed in an artificial aging, because the target is to verify the limits of the analyzed things.

[Marty Kasprzyk]

On 8/3/2024 at 8:14 PM, Don Noon said:

Linseed oil and oil varnish add damping, which smooths out the distinctive harsh, fuzzy sound of an unvarnished violin.  I think it's mostly attenuating the highest frequencies.  I have experimented a bit with this, with the conclusion that a minimal thickness of varnish is good, and more is too much.

I have not done much in the way of repairs, and have no personal experience with thuddy plates from superior violins.  I would hesitate to attribute the thuddy taptones to any kind of beneficial damping that can be added in some way.  There could be other things going on that would make for a non-ringy free plate.  Micro-cracking at the edges, hemicellulose degradation that would affect the crossgrain stiffness, or free plate mode energy transfer from the taptone to some other twisting or flapping mode.

For the thuddy plates of good violins, I'd want to know things like... new or old?  normal taptone frequencies?  unusual relationship between taptone frequencies?  how much varnish is there?  antiqued?  

It's difficult to add damping without adding some mass and stiffness which also affect the sound character.  If you just wanted to increase damping micro-cracking could produce this.

Water expands about 9% when it freezes which may stress the wood's structure enough to cause micro-cracking. Repeated soaking, freezing, thawing and drying of the wood might work.

One variation would be to soak the wood, freeze it and then use vacuum freeze drying to remove the water. I might try this on one of the violas I built.