The effect of string quality on wood memory

Choice of classical guitar strings and technical issues connected with their use.
BellyDoc
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Re: The effect of string quality on wood memory

Post by BellyDoc » Fri May 12, 2017 3:55 pm

guitarrista wrote:
Thu May 11, 2017 4:19 pm
Apparently there are quasi-permanent changes in the wood nanostructure dependent on moisture, temperature and stress-loading. This is probably what is referred to a guitar "opening-up" - the formation of these frozen nanostructure strains - as a result of continuous loading from the strings and possibly due to some residual drying.

In other words, the influencing factors are the usual suspects - and they do not include vibration differences from old vs. new strings :-)

Here's an excerpt from a recent freely-available paper I found on "wood memory":


woodmemory.JPG
Reading the first line, they're describing a MODEL, i.e., a computational tool that reflects what they THINK is going on in the real world. It's used to make predictive calculations. Insofar as the model makes useful and accurate predictions, it adds indirect evidence to support the belief that the components of the model, (the assumptions about real world phenomena) are accurately described. I don't know how much weight to put on this as evidence that a guitar would retain some sort of behavior memory with regard to it's vibratory characteristics over string changes. My understanding is that the differences between the sounds of different strings is just which partial harmonic overtones are emphasized and how much. All of these partials are going to be present at some amount anyhow. The soundboard still has to vibrate with all of them.


That said, ship builders have known that wood has a form of memory for millennia. The tree flexes back and forth in the wind for hundreds of years before it's harvested. Expecting a board to survive flexing in the hull for a few decades is trivial by comparison. That's a sense in which wood has "memory". The point of describing this as memory, though, is to call out the OPPOSITE behavior to what is being discussed here with respect to soundboards. Memory, here, is the lack of change in the material, not the retention of change. The point is that unlike modern composites or metals, the properties of wood stay the SAME over millions of flex cycles. That's the memory. Metals fatigue as their crystal structures change and "work harden" to become stiffer, composite polymer matrices microfracture and become softer. Wood has this form of "memory" though and bounces back to where it's always been. It stays the same, longer.

My understanding is that one of the contributing factors is that the portion of wood most useful for us is "heartwood" which is no longer part of the circulatory system of the trunk. The hollow cellulose tubules that once carried water and nutrients have long since been filled in with a dense protein called lignin. Heartwood's main role for the tree is to be like a central bony support for the living tissues on the outer surface. Lignin is interesting because, like all proteins, it's a polymer of amino acids, and adjacent chains of amino acids are linked together into a network with disulfide bridges. Disulfide bridges aren't super strong molecular bonds, but they do have some interesting properties. They can break under strain and then reform spontaneously, like magnet latches or velcro. This is one of the reasons that cyclic flexing doesn't deteriorate the overall strength of the material. It's also why heating and bending and then cooling can be used to shape wood.

Personally, I've had nothing but excellent service from Strings by Mail and I'm certain to order from them again, so a bit of self serving advertisement on their part doesn't bother me at all. :)
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chrispeppler
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Re: The effect of string quality on wood memory

Post by chrispeppler » Fri May 12, 2017 5:15 pm

I have a 1970 Yairi classical guitar and decided to research its history. During this process I came across a report that Gi’ichi Yairi, the first in a line of Yairi luthiers, stored his finished instruments in a shed for months and ‘bathed’ them in quality musical performances. His belief was that the guitars would somehow absorb these sounds and become better instruments. At the time I took this to be the charming practice of a dedicated guitar maker, but no more than this. However, more recently, a scientist by the name of Rupert Sheldrake has proposed a ‘morphogenic resonance’ theory that holds that both organic and inorganic objects are influenced by unseen ‘energy’ fields’ that exist in some alternate dimension. Before the advent of Quantum Physics this would probably have been laughed at, but Quantum science makes allowance for other dimensions and non-Newtonian interactions. So, who knows, perhaps a guitar can be influenced by musical energy which effects its morphogenic field without changing the physical constitution of the wood in any way. This would be different to the ‘opening up’ that occurs when the wood and joints settle under string pressure and playing stresses, and would not be revealed by any known scientific tests. Just a thought 

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Re: The effect of string quality on wood memory

Post by BellyDoc » Fri May 12, 2017 5:26 pm

I'm going to have to give that a quantum chuckle. :)

I really like where this goes!

Fortunately for me, if the physical proximity of beautiful music is unrelated to the strength of it's unseen field effect in time and space, then I can sternly remind my guitar of this on my way to this afternoon's lesson. I will hope it complies with new found post Segovian resonance and get back to you with my result.
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guitarrista
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Re: The effect of string quality on wood memory

Post by guitarrista » Fri May 12, 2017 5:59 pm

BellyDoc wrote:
Fri May 12, 2017 3:55 pm
guitarrista wrote:
Thu May 11, 2017 4:19 pm
Apparently there are quasi-permanent changes in the wood nanostructure dependent on moisture, temperature and stress-loading. This is probably what is referred to a guitar "opening-up" - the formation of these frozen nanostructure strains - as a result of continuous loading from the strings and possibly due to some residual drying.

In other words, the influencing factors are the usual suspects - and they do not include vibration differences from old vs. new strings :-)

Here's an excerpt from a recent freely-available paper I found on "wood memory":


woodmemory.JPG
Reading the first line, they're describing a MODEL, i.e., a computational tool that reflects what they THINK is going on in the real world. It's used to make predictive calculations. Insofar as the model makes useful and accurate predictions, it adds indirect evidence to support the belief that the components of the model, (the assumptions about real world phenomena) are accurately described. I don't know how much weight to put on this as evidence that a guitar would retain some sort of behavior memory with regard to it's vibratory characteristics over string changes.
I would say none, since my point based on this paper was that "the influencing factors are the usual suspects - and they do not include vibration differences from old vs. new strings". Not sure how you interpreted this to mean the opposite - i.e. that I think the paper is evidence in favour of the SBM claim.
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Re: The effect of string quality on wood memory

Post by robin loops » Fri May 12, 2017 8:10 pm

While good vibrations make a guitar 'open up', the idea that bad vibrations will cause it to 'close up' (for lack of a better term) I personally find ludicrous. Sounds like a cheesy sales tactic to me.
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Re: The effect of string quality on wood memory

Post by Keith » Fri May 12, 2017 11:00 pm

robin loops wrote:
Fri May 12, 2017 8:10 pm
While good vibrations make a guitar 'open up', the idea that bad vibrations will cause it to 'close up' (for lack of a better term) I personally find ludicrous.
what about not opening up as fully and/or as quickly?
be true to the one you love but have many flings with different guitars

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Re: The effect of string quality on wood memory

Post by Bill B » Sat May 13, 2017 1:31 am

bwahahahahahaha!
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BellyDoc
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Re: The effect of string quality on wood memory

Post by BellyDoc » Sat May 13, 2017 1:33 am

guitarrista wrote:
Fri May 12, 2017 5:59 pm
BellyDoc wrote:
Fri May 12, 2017 3:55 pm
guitarrista wrote:
Thu May 11, 2017 4:19 pm
Apparently there are quasi-permanent changes in the wood nanostructure dependent on moisture, temperature and stress-loading. This is probably what is referred to a guitar "opening-up" - the formation of these frozen nanostructure strains - as a result of continuous loading from the strings and possibly due to some residual drying.

In other words, the influencing factors are the usual suspects - and they do not include vibration differences from old vs. new strings :-)

Here's an excerpt from a recent freely-available paper I found on "wood memory":


woodmemory.JPG
Reading the first line, they're describing a MODEL, i.e., a computational tool that reflects what they THINK is going on in the real world. It's used to make predictive calculations. Insofar as the model makes useful and accurate predictions, it adds indirect evidence to support the belief that the components of the model, (the assumptions about real world phenomena) are accurately described. I don't know how much weight to put on this as evidence that a guitar would retain some sort of behavior memory with regard to it's vibratory characteristics over string changes.
I would say none, since my point based on this paper was that "the influencing factors are the usual suspects - and they do not include vibration differences from old vs. new strings". Not sure how you interpreted this to mean the opposite - i.e. that I think the paper is evidence in favour of the SBM claim.

Apologies! I was unclear.

My point was to agree with that particular point of view, and identify where people are equivocating on the use of the term "memory". While it does mean something about structural integrity under cyclic load, or calls out a property of the material that allows it to be heated and bent, it certainly doesn't mean that there would be any changes in it's musical properties based on what it's recently listened to.

... or does it?

I listened to the Symphony Hall channel on Sirius XM on the way to my lesson just now, and turned it way up with my guitar right there in the back seat. Following that, I had one of the best sessions I've ever had. No joke. It really went well. I'm on cloud nine right now!

Coincidence?

:lol:
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Re: The effect of string quality on wood memory

Post by Keith » Sat May 13, 2017 10:13 am

I believe the Tone-Rite device, aka, marital aid for a guitar, is sold as a device to accelerate the change (opening up) process. Whether or not it does it is open to debate. That said, it seems reasonable that constant vibration via playing does change the structure of wood and over time cellular changes do occur. Of course vibration is not the only factor but one which has some possibilities for variance under players' control. Weak players or noodlers are not going to get a guitar moving as well as a good player and changes due to vibration is not going to happen or will happen slowly. Likewise, it seems reasonable that a string which does not vibrate close to its potential, that is, worn strings (primarily bass strings) will not get the vibrations to maximum potential.

The statement made by SBM might be a little over the top but it seems reasonable within the sphere of getting the maximum potential out of the guitar and fresh strings is a good way to "run on all 8 cylinders" and that is SBM bailiwick.
be true to the one you love but have many flings with different guitars

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Re: The effect of string quality on wood memory

Post by Beowulf » Sat May 13, 2017 1:12 pm

My tongue is out of my cheek now after the audio speaker analogy... :D

Wood is an organic material and our bodies are composed of organic materials (mostly...we hope!), so there are similarities. For example, a guitar's environmental humidity should be roughly the same as is preferred by the human body. When any of us sits down to play, our hands need to "warm up" and playing with cold hands is not that rewarding. Warming up improves flexibility, placement accuracy, fluidity, strength, control, etc. How do the hands warm up? Friction from movement. Do my hands retain a memory of the movements before they were warmed up and does this adversely affect my playing? I don't think so. The soundboard of the guitar vibrates in response to the vibratory movements of the strings which are transferred through the saddle and the bridge. This vibration of the soundboard results in friction as the soundboard flexes and creates...heat. Thus the soundboard does "warm up".

Spruce and cedar soundboards behave differently: cedar takes less time to reach its potential, whereas spruce will take years to "open up" and reach its potential. There are differences in the actual structure of the two woods: Spruce has a higher density/specific gravity than cedar (which is a lighter wood) and also contains more resin. Thus spruce takes a longer time to "warm up" and after being played for some time the structure retains a tendency (memory) to vibrate in particular patterns or modes. These modes are the vibration patterns that the soundboard is predisposed to exhibit due to density variations, resin variations and wood fibre patterns in the specific soundboard. Not having played a cedar top instrument over a long period of time, perhaps someone who has can comment on changes that occur with cedar.

After playing the same spruce top guitar for over 40 years, I can say from my experience that playing with old strings has resulted in no harm whatsoever to my instrument. Would it sound any different if I had never played with worn strings? I can only say, I doubt it. Does a guitar played by a very poor player result in damage to the instrument's sound that is "remembered"? I don't think so. A lovely little apocryphal story about Segovia: He once attended a dinner party and when asked, agreed to play for those present. His playing was wonderful and the sound was so good that the audience assumed he had brought his concert instrument with him. Not so, he was playing on a student guitar owned by his host.
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Re: The effect of string quality on wood memory

Post by ddray » Sat May 13, 2017 6:37 pm

Beowulf wrote:
Fri May 12, 2017 12:57 pm
I have learned to avoid playing poor recordings or poor performances through my audio system speakers so as to avoid harming my speakers' sound temporarily or permanently. The speakers remember the ugly sound and thereafter will become conditioned to sound terrible even with good recordings or performances. :lol:
I was thinking along the same lines. All the sour notes I've hit on my guitar have traumatized it beyond remedy :D

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Re: The effect of string quality on wood memory

Post by martinardo » Sun May 14, 2017 12:00 am

Basically if playing worn out strings influences the wood, then after some time with new strings the wood would have decided to stick to that time with old strings permanently? If so, since the guitar was built with new strings first, this structure would then be remembered even if strings are worn. Kinda paradox...
Clearly this is why there are so many wealthy "timber (or possibly timbre) based" psychiatrists

specializing in bi-polar and other disorders affecting our beloved instruments. One notably successful,

albeit expensive, treatment in many sad cases is a sojourn on the sand near a surfing beach to dispel

the bad vibrations. Unfortunately the salty air tends to quickly corrode the new strings; thus turning

them to old strings. So, for some wooden entities, the terrible cycle begins again . . .
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Re: The effect of string quality on wood memory

Post by Bill B » Sun May 21, 2017 1:40 am

Beowulf wrote:
Sat May 13, 2017 1:12 pm
....... This vibration of the soundboard results in friction as the soundboard flexes and creates...heat. Thus the soundboard does "warm up".
Ok, this sounds likely. But how much? Has anybody ever measured the amount of heat generated by a vibrating guitar top? Surely somebody?
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Beowulf
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Re: The effect of string quality on wood memory

Post by Beowulf » Sun May 21, 2017 3:13 am

Bill B wrote:
Sun May 21, 2017 1:40 am
Beowulf wrote:
Sat May 13, 2017 1:12 pm
....... This vibration of the soundboard results in friction as the soundboard flexes and creates...heat. Thus the soundboard does "warm up".
Ok, this sounds likely. But how much? Has anybody ever measured the amount of heat generated by a vibrating guitar top? Surely somebody?
This would take some very sensitive temperature probes attached to the soundboard. I doubt anyone has done it, though perhaps sensors placed just above the soundboard surface would do the trick. I wonder if anyone has measured the increase in hand temperature as one's hands warm up? Nevertheless, there is no doubt that friction from movement creates heat and the increased energy in the molecules of the wood will affect the vibration characteristics of the wood.
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Re: The effect of string quality on wood memory

Post by pogmoor » Sun May 21, 2017 10:30 am

Beowulf wrote:
Sun May 21, 2017 3:13 am
Nevertheless, there is no doubt that friction from movement creates heat and the increased energy in the molecules of the wood will affect the vibration characteristics of the wood.
An imperceptible rise in temperature will lead to an imperceptible change in the sound.
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