Don Noon

300+ year old Spruce

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Don Noon   

Melvin Goldsmith was kind enough to send me some samples of very old Italian Spruce.  Unfortunately they weren't big enough to build into a fiddle, but they were big enough to test.  They were from two different trees.

 

Speed of sound was obtained by compression wave resonance, and damping by the free-free resonance decay time.  I also used one sample to test for speed of sound via the free-free resonant frequency and back-calculate speed of sound based on dimensions and weight.

 

I then cut some identically-sized samples (using just the one old wood sample dimensions) from some 30 year old Sitka I've had laying around, some old Engelmann, and ponded Sitka.  The results:

 

post-25192-0-09431100-1416629010_thumb.jpg

 

The Old Wood doesn't stand out as anything exceptional when viewed against my entire database of unprocessed wood measurements, although it does tend to lie in the mid to upper regions of speed of sound.  I'm not sure why my other samples, cut to the same dimensions as the one in the upper right, were so low in speed of sound.  I expected a bit more.

 

Damping isn't worth showing... it came out right about in the middle of the pack for all of the samples... old, ponded, whatever.

 

Visually there's nothing either, although the Engelmann sample (not shown) was much lighter, except for the fungus stains.

post-25192-0-76638900-1416629011_thumb.jpg

 

It would be so much more enlightening if I could test some new wood, then test it again every 10 or 20 years until it's 300 years old.  Wood is so variable that it's impossible to say what is natural variation and what is due to age.  However, there's is something here to say there might be a tendency for old wood to be higher modulus.  I think most people kinda believe that anyway.

 

It should be noted that there are other potential influences that are not tested here:

-Any effects due to vibration

-Any effects due to thickness (this wood spent most of its life fairly thick, so if oxidation or humidity cycling have to work their way through the wood, it might not show up well)

-Effects of small sample size (these might not be representative)

 

These unimpressive results don't mean I no longer have interest in old wood.  I still do.  So if there are any offcuts of ancient wood lying around, (maple too), I'd like to test them.  PM me.

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For a meaning result you have to compare a same wood when it was new and when it was 300 yrs old.

 

Or you have to have many more samples.

 

Each wood is so different in many ways,not just the speed of sound or density or damping,one old sample doesn't tell you much.

 

KY

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Don Noon   

Each wood is so different in many ways,not just the speed of sound or density or damping,one old sample doesn't tell you much.

 

At least, it tells you that 300 years doesn't convert all wood into something radically different.  The numbers are still on the chart, so it still mostly looks like wood.  Better to have one or two samples than none.

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jezzupe   

Don what is the smallest size you can use dimension wise? I have some very old spruce and redwood, to me it would be interesting to see how the redwood compares to the spruce.

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Don Noon   

Don what is the smallest size you can use dimension wise? I have some very old spruce and redwood, to me it would be interesting to see how the redwood compares to the spruce.

200mm long is great, but I can deal with 100mm long.  As long as it's at least a few mm in the other dimensions, I can get speed of sound pretty well.  For damping, I like to have it wider, 10mm or more.

 

Would it make a difference if used as sound post material?

I don't know that anyone has shown how soundpost wood properties influence anything, other than the mind of the person putting it in.

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mrbadger   

There is some contemporary research on how wood changes over time. This rheological research offers some insight into how wood behaves over time under bending and loading forces, and how the molecular bonds respond with differing behavior for cellulose, hemi-cellulose and lignin.

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Thank you for sharing your interesting research. 

 

I am trying to get a feel for the graph. To the left and up would be better for sound conduction?

 

Do you use this tool to decide which wood is worth using? 

Where can I read more about the heat treatments?

 

What about freezing?  

Here in Canada you can 'freeze-dry' some green wood outside in the winter, but I wonder if that is affecting the wood properties somehow.

 

Pentabass

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Don Noon   

I am trying to get a feel for the graph. To the left and up would be better for sound conduction?

 
For flat-plate bending, yes... in theory.  But violins are not flat plates.  In actual practice, I think going too far to the left (low density) has some drawbacks.
 

Do you use this tool to decide which wood is worth using? 

 
The chart is mostly for visualization, but I do tend to avoid wood that's too dense or if the speed of sound is too low.  I have a box of extremely dense wood with low speed of sound, and if I used a fireplace, that's where it would go.
 

Where can I read more about the heat treatments?

 
 Google "wood heat treatment"
 

What about freezing?  

 

I hope to never find out... that's why I'm in So. Cal.  B)

I would be a bit worried about ice expansion doing damage to the cells.

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With all due respect to you and the modern measuring methods au courant    What part of any of the Strads and Del Gesus, Guads, etc. that you have spent your entire luthier life emulating  have not been made out of 300 year old wood?

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What about freezing?  

Here in Canada you can 'freeze-dry' some green wood outside in the winter, but I wonder if that is affecting the wood properties somehow.

 

Pentabass

 

(for spruce)

 

It doesn't affect wood properties to freeze-dry it outside. That's what wood is designed to be capable of. However it dries better inside than outside when it's cold outside, because humidity drops even more inside when it's really cold outside.

 

When storing and seasoning wood outside for 10+ years, in a climate where you live, the cycling will break down the wood so that the crossgrain stiffness is lower compared to along grain.The wood will feel "soft" under gouges,but still be strong along grain.

When tuning the plates with this type of wood, it will have a M2 that is lower than normal, ~150 Hz.

 

Heat treatment to such wood does not make it creap in a normal way, it is not so sensitive to humidity changes, beacuse it will not retract much cross grain.

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How thick were these pieces of Italian spruce originally before you cut them ? I think they would need to  have been similar thickness to violin plate dimension(3mm or so) for the last 300 years  to have any meaningful result , as wood is affected by the atmosphere more than anything else and thick wood wouldn`t be affected the same. This is discounting any secret :) wood treatment the Italians used.

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I'll be interested in very old spruce or maple.(How the properties of wood changes over 300 yrs .)

 

Hope you get more samples.

 

Do you check Young's modulus too?

 

I'd like to know more about your set up for the speed of sound and damping.(diagrams or photos)

 

KY

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Don Noon   

There is some contemporary research on how wood changes over time. 

Links or references??

 

With all due respect to you and the modern measuring methods au courant    What part of any of the Strads and Del Gesus, Guads, etc. that you have spent your entire luthier life emulating  have not been made out of 300 year old wood?

I'm not sure what you're asking with this.  I'm simply trying to find out if old wood has any observably different properties.

 

How thick were these pieces of Italian spruce originally before you cut them ? I think they would need to  have been similar thickness to violin plate dimension(3mm or so) for the last 300 years  to have any meaningful result , as wood is affected by the atmosphere more than anything else and thick wood wouldn`t be affected the same. This is discounting any secret :) wood treatment the Italians used.

I don't know how thick the pieces were, but I think they were very thick for most of the time.  Come to think about it, the wood in trees can be extremely old (especially in the middle) even before they are cut down.

 

Do you check Young's modulus too?

 

I'd like to know more about your set up for the speed of sound and damping.(diagrams or photos)

Modulus can be calculated from speed of sound and density.

I usually use this method: http://www.maestronet.com/forum/index.php?/topic/321492-ridiculously-easy-way-to-measure-speed-of-sound/

Or the free-free frequency of a rectangular sample, back-calculating properties through the beam equations.

More info and photos here: http://jpschmidtviolins.com/What_You_Can_Find_Out_By_Hitting_Things.pdf

 

Did the pieces give a chance to measure crossgrain properties?

Perhaps they will be more affected by age.

There were one or two pieces where I could measure crossgrain, and it too was not anything out of the ordinary.

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I'd be interested in how you use the information when selecting the wood.

 

Do you match to similar wood?

 

Can you kind of  predict which'll have higher tap tone or lower tap tone etc using your test results?

 

KY

 

PS :What's your set up for measuring the speed of sound? Thanks.

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Don Noon   

I'd be interested in how you use the information when selecting the wood.

 

Do you match to similar wood?

 

Can you kind of  predict which'll have higher tap tone or lower tap tone etc using your test results?

 

KY

 

PS :What's your set up for measuring the speed of sound? Thanks.

 

I don't have any set formula for deciding what wood is good and what isn't.  But I do look for high speed of sound and high Q (low damping) in whatever density I might want to use, as that would seem to be more efficient at producing sound.  I'm still experimenting, with no firm answers, other than everything ends up sounding different.

 

As for tap tones... theoretically, high radiation ratio should give a higher frequency for a given plate weight (with some disturbance from arching), and that seems to hold true, mostly.  

 

PS:  see the links given in post #17

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Don, I know that this suggestion doesn't do much for you, but perhaps you should test and document some wood samples and pass the samples on to an interested young person to carry on with in the future. If they don't drop the ball at some point, the changes over time could be documented.

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Addie   

I don't know that anyone has shown how soundpost wood properties influence anything, other than the mind of the person putting it in.

I seem to recall a research paper that said wood properties don’t matter, other than weight.  Probably by McLennan?  

 

Older lit specifies close grain, and grain perpendicular to the top plate grain, to prevent imprinting of the harder rings of the post into the top.  The two may be related, or both could just be violin lore.

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Don Noon   

I seem to recall a research paper that said wood properties don’t matter, other than weight.  

 

I dare anyone to make a violin out of wood with zero modulus.

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Addie   

I dare anyone to make a violin out of wood with zero modulus.

In the context of sound posts made of spruce tone wood... wood properties don't matter.     

 

Please see   #8   for context, which I also included in my now misquoted post.   <_<

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