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Why new Instrument sounds better after play??


Mudoe

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I will start off by saying that I believe in the break-in effect. I have noticed it quite a few times. On two occasions over the last three or four years, I was stuck with no viola to play in orchestra except inexpensive Chinese instruments. The recent one is a white instrument I bought as part of a line of instruments used to test varnishes. I did no other work to it. It has become much more responsive and flexible for me. This again may simply be my own learning curve, but I am willing to admit it MAY have broken in. It has opened up, at least to my perception. I have no way to give measurments because I took none.

Now as to the statements of xyz1000 and this most recent one of GlennPark Pa: XYZ says creep may be involved but does not say why this should be involved with "opening up". If there is fatigue and increased flexibility, any fatigue invloving damping should broaden and lower a resonance, contrary to what XYZ implies. (If there is no damping, the resonance just shifts in frequency) If the loosening up involves some lowering of stiffness or increasing of damping that should be discussed. Lowering the frequency of a mode with no change of damping is not likely to be relevant. One could have anticipated that in graduations of the wood. If there may be increased damping, its possible role is not discussed.

To summarize, if it is a simple matter of lowering stiffness, one should see mode frequencies lower, and the shape of resonance curves stay the same. If damping is increased, resonances should broaden and be lowered. That is elementary physics.

What I do not understand are all the plaudits to scientistic restatements about the old intuitive notion of "loosening up". That is subjectively what happens, but the models and their suggested implications are not born out by the physics. It is just old wine in new bottles. The new bottles are pseudoscience, and careless statements, but not legitimate physical statements. Again, I repeat that I sense truth in the breaking-in observations, but this thread has done nothing to suggest a mechanism for this effect.

The power of a re-stated prejudice is best reflected by the posting of Mr. Coggins who writes, "Thanks xyz! - speaking as someone who's eyes glaze over and thoughts turn to bottles of red wine at the mere mention of words like "eigenmodes", I found your explanation to be the clearest and most understandable I have ever seen. "

And XYZ1000, you never did discuss creep and how it may lead to damping or in fact the simple shift of resonances, and how that would affect the perceptions of sound. All the tag words you listed for researching on the net...... they are all quite familiar to me, and I have looked into this a good deal. And for quite a long time.

Somebody else, a person I may not wish to offend, has put 5 stars on this thread. I cannot understand why. The thread contains almost nothing of worth...... It is simply a rehash of what people have always believed. There is no physically relevant material that I can see.

I notice that one of our posters is a retired physicist. I wish he would weigh in on this one.

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The 'science types' answered this question years ago. Strips of spruce taken from violin tops were mechanically excited to resonance at their fundamental vibrations and it was found that the amplitude of vibration increased steadily over an hour or two. Leaving them for a day or two allowed them to revert to their original stiffness. In other words, the fibers of the belly really do loosen up with playing but the playing needs to be regular otherwise you are back to square one.


From theory to experimental verification all within a matter of days – that’s pretty good . The experiment you describe is a good one since it separates the two regimes I was thinking about. This one is involved only with the wood stiffness and not the stick-slips associated with joints. References would be good, although it’s unlikely I’d ever take the time to find a library that carries Catgut Association Society Journal or an equivalent one. What I’m surprised about is the time involved – that the amplitude increased after an hour or two. Perhaps the testing was done with accelerating the effect in mind. The posters here describe a longer-time effect. Thanks for the info, GlennYork.

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Dear XYZ1000,

It will be sufficient for me if you talk about creep, hysteresis, and resonances in general. Undamped ones or ones whose damping may eiher increase or decrease. But please say something about the physical processes, and which ones are most closely related to the effects discussed by the makers. (Hysteresis is what I called short time-scale visco-elastic creep in an early posting. This will be active in a single cycling of the material, and the time scale is a millisecond.)

I think you can assume without much trouble that that the cell-walls are cemented with lignin, and that the rest of the material strength comes from cellulose fibers that are hydrogen-bonded. There is also hydrogen bonded hemi-cellulose which is weaker than cellulose and also branches more randomly, with other than glucose molecules in the polymer. Xylose for example. This can bind to the cellulose and lignin, also. I do not know how this will affect your picture of such a polymer.

Also keep in mind that the substance is not just a polymer. It is cellular: hollow boxes of primarily cellulose and hemicellulose fibers are stacked and glued with lignin. It may even be that the word "cellulose" comes from this common appearance in nature.

If you mean to say that the flexing decreases the hysteresis of such a structure, please say so. It is not necessary to explain why, because this is likely to be an adressable problem. In fact, it may very well be what underlines all of this effect you are trying to describe.

So, as to the materials you are familiar with, do you find that hysteretic losses become less when they are vibrated for a while? That is, when they are cycled through many cyles of a normal mode by being excited or vibrated ? (Please answer at least this one for the record. That seems to be your area of expertise.)

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Somebody else, a person I may not wish to offend, has put 5 stars on this thread. I cannot understand why. The thread contains almost nothing of worth...... It is simply a rehash of what people have always believed. There is no physically relevant material that I can see.


In my opinion, about 98% of what's been discussed within this forum has already been discussed, at some point in time, but that doesn't mean that some, or even a lot of it isn't new information to "somebody". That's kind of what these internet newsgroups, not to mention 98% of anything discussed or published is all about. Within this forum alone there are a lot of the same questions and discussions repeated over and over again, but I see nothing wrong with that since not only does active discussion spawn new ideas, but it is also useful to those who are new to the topics and ideas being discussed.

Concerning those stars, I'm not sure, but I think they are now put there automatically by the script running the forum based on the number of replies. Even if they aren't, if someone actually put them there then it's likely that the subject was of interest to them, and typically if a subject is of interest to one person, it's also of interest to at least one or more others. If someone who thinks they contributed some extremely bright ideas added the stars to either aid in gaining further recognition for their ideas, or in hopes of getting more feedback on their ideas, I don't see anything wrong with that either, do you?

If you find something worthwhile in this forum take it and leave the rest alone. Likewise if you think you have something worthwhile to share, then by all means share it and hopefully others will appreciate, rather than criticize you for having done so.

Tim

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It will be sufficient for me if you talk about creep, hysteresis, and resonances in general. Undamped ones or ones whose damping may eiher increase or decrease. But please say something about the physical processes, and which ones are most closely related to the effects discussed by the makers.


Let me state a second time that I am no expert when it comes to polymer science and I’ve never studied wood or violin (or any instrument) sound scientifically. So talking in general is really all I can do. I’m intrigued about the interplay between violin making and science. If you’re looking for expert explanation, I ain’t it.

Creep is the change in strain (length) over time for a given stress (force). If you put a 10 pound weight on top of a piece of wood, the wood length will change. If the weight remains there for one year, the length will change more compared to when the weight was there for only one second. It’s not a far extension that this same phenomenon (not necessarily called creep, but the same phenomenon) applies to how the violin might sound after playing it continuously from when new. When playing the violin, the back vibrates to some amplitude. The vibration is the equivalent of the stress. Over time, the amplitude increases. If a player plays a note the same was as when the violin was new, but this time the violin vibrates with increased amplitude, then certainly the sound will be different. And that is where I think there is a connection between creep and the violin opening up.

Of all the effects discussed by makers, I believe that this and the stick-slip ones are the most dominant. On a microscopic level (cells and bonding), I will have to defer that to experts.

Quote:

So, as to the materials you are familiar with, do you find that hysteretic losses become less when they are vibrated for a while? That is, when they are cycled through many cyles of a normal mode by being excited or vibrated ? (Please answer at least this one for the record. That seems to be your area of expertise.)


I am familiar with metals, but I’ve never vibrated them nor have I looked into the “cold flow” described by a previous poster.

Okay, where's the wine? Don't leave me hanging here.

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Creep is very close to what the word would suggest.

Your statements don't really enlighten at all. Vibration equivalent to stress? Vibration involves inertial mass and a force. These are distributed per volume in a continuous body, and stress is now different from "force" of course. Yes, but everybody knows that. Where this is related to breaking in of a violin is not apparent to me.

" If a player plays a note the same was as when the violin was new, but this time the violin vibrates with increased amplitude, then certainly the sound will be different. And that is where I think there is a connection between creep and the violin opening up. "

Maybe a connection ... what is it and why ? You are repeating yourself. In other words, you are not saying anything at all about what is going on.

You will have to talk to the others if you want anyone to buy you drinks.

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Tim2,

" If you find something worthwhile in this forum take it and leave the rest alone. Likewise if you think you have something worthwhile to share, then by all means share it and hopefully others will appreciate, rather than criticize you for having done so. "

That is what I have tried to do. That includes questioning questionable postings. If others are "getting something" I don't mind at all. If they think they are getting something and are actually not, that is also fine with me.

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Nope, Stradivari had no notion of any kind of dynamics. All of that started with Newton who died about the time of Tony's birth. Further developments were slow. Also, it takes a LONG time for any academic discipline to filter down to the masses. The business of materials science is modern.

Besides, the discussion is about things that happen AFTER the violin is made. That should be pretty clear by now.

By the way, are people here offended by controversy? To call one's bluff.... is that even controversy ?

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Alan, Michael, and others

I'll join you in your vigil. Wine at 6:00. Oh-oh, it's 6:00 now. We could take three 8-hour shifts. Michael, do you want the daytime or evening shift?

The $64 question

I think we have a fundamental question here. Michael's violins and the Strad he mentioned got less bright, or at least less noisy as they were played. One recently made violin that I played severely lacked brightness, richness and power when it was new, but has matured into a somewhat dark, yet fairly rich and powerful violin, with a great increase in the treble sound. So one got brighter, and the other one darker. The question is, are we increasing or decreasing the damping? If we can't agree on that, we won't get far.

I think we are decreasing the damping in the middle and low frequencies. I think that would explain all the observations. By "loosening up", I suspect that the material or structures that cause damping in the wood are broken down a bit. Older violins just sound a little more resonant to me than new violins.

GlennYorkPA,

Finally, we have the results of a simple, hopefully definitive experiment. Now if we can only figure out where you saw it. We're counting on you.

That wood experiment appears to confirm my hypothesis that playing in is caused by a decrease in damping. Assuming that the results are as you said, the only possible explanation is that the Q of the wood increased. [Q is explained below.] Since the wood was excited at the resonant frequency, a change in stiffness could not have caused the increase in amplitude. That would have shifted the resonant frequency and reduced the amplitude instead of increasing it. Since the mass didn't change in a couple of hours, the damping coefficient must have decreased and the Q increased.

Assuming the experiment was done correctly, it is now established that wood becomes less damped with vibration. We don't know about the purfling and glue and all the other stuff, but the wood does undergo a change that could account for improvement of violins with playing. The change is partly reversible, in agreement with our observations on real violins!

Some remaining questions

In which direction was the wood excited? Is there a long-term change? Is there a really long-term change? How does static stress affect the Q and resonant frequency? How much of the change is reversible? How does old wood react? Can old violins really get "played out"? Now the big questions. What causes the decrease in damping? What have we been smoking? What wood treatment will enhance this effect to just the right extent?

Summary

About all we seem to know for sure is that violins get more resonant as they are played (think higher Q). Drat. We knew that already. But at least we now have some evidence on the mechanism.

GlennYorkPA and other amateur and professional wood types, you're on. Time to shine. Now is definitely the time to review what we know about aging and torturing wood.

==================================

Footnote: Explanation of Q

The Q factor, which is inversely proportional to the damping coefficient or the damping force, is the "quality" factor of a resonating body. Left alone to vibrate, a harmonic oscillator will vibrate at its own resonant frequency. An undamped harmonic oscillator is hard to get vibrating except at the resonant frequency, where it vibrates vigorously out of control. If you add a damping force, it can be more easily excited at other frequencies. The amplitude is still greatest at the resonant frequency, but the peak response is smaller than without damping. In other words, the peak is lower and broader. In a violin, you need some damping. Otherwise one note would be very strong, while other notes would be very weak. But too much damping will smother the sound.

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Did I say "apparently" darker? If not, I guess I should have. The lack of high frequency noise isn't really darker. And the loosening up I sense could encourage the idea of brighter. I often find that my words don't mesh with those of violinists. :-) How about if we say they get darker and brighter at the same time. Or maybe we should say they get better, unless I didn't make them, in which case the same thing means "worse". Language; ain't it great!

There's another thread similar to this one on the yahoo "Luthiers" board, about vibration de-damping, which is the violent way to do what we're talking about (get one of those bed vibrating motors and hook it to your bridge, essentially).

I'st 6:45 here, and I'm about to start the wine. Don't let me stop anyone. I suspect that we'll all want to cover the evening shift, wherever we are. . . I hope. :-)

---Later: sorry, it's not the "Luthiers" board I should have pointed to; it's "Leftbrain Lutherie".

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My personal observations imbibe from experiences attributed to neither of the foregoing; rather, an extreme desire to examine those pre-existing sequences which have been extricated beyond the practical limits for which they were designed. No matter, the flow of wood being first observed by ancient loggers on their way to the mills down-river. Space here, being limited, allows none of the parameters required for ample exposure. Sorry for this "pared-down" version, but sincerely hope it clarifies the fundamental questions put forth.

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I don't really relate to any of the talk of creep as it applies to the wood of the violin. At one point in my life I spent the days rolling metal with an english wheel, as well as with moving it around with dolly and hammer and changing it from one state to another with heat, but I don't think any of those principles apply to the wood, and if so it's so minimal that it can probably be ignored.

I think the process is simply a matter of what's happening within the cells of the wood, and I think the most effect occurs across the width of the instrument rather than longitudinally. I wonder if perhaps the vibrations across the width causes the material within the cell structures to be forced against the opposing grain and then in a period of time of no vibrations, the cell structure simply returns to it's original state.

There are a lot of variables to also concider. Wood that's cut from the same stand at different times of the day would have a different cell structure from one to the next. How about wood that's split and left standing upright rather than laying horizontal over a period of time? Would two violin tops cut from the length of a aged split log (cut end to end) produce a different result than two tops that were cut from a split log that was originally cut to about the length of the top? I can see by the pic of the top plate of the viola that michael is working on (marking the plate thickness) that the grain pattern is tilted slightly towards the center of the instrument and wonder what the difference would be between the play-in of a plate with that grain orientation versus one that was more vertical.

Tim

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I have been following - reading - this thread with interest since I have experienced the effect on an older violin being returned to service and well I'm a bit of a technophile. On my violin the effect was similar to the removal of a mute, the overall tone be came fuller and more complex. Am I right in thinking that part of the descriptive nomemclature problem is that the result of the effect is expressed differently in each violin due to the individuality of the structure of the wood and the carving?

Of course when you all loose me, I just want to ask, what's in that bottle of red over there? I'll take a glass.

(spelling damn spelling)

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