Guitar woods? Bah humbug!

[redir]

Hmmm, I didn't know Jerry Garcia played a classical guitar.

[Alan Carruth]

I can attest to the fact that we hear a lot with our eyes, or, at least, have a strong tendency to hear what we want, or expect, to hear. That's the whole reason we need to rely on 'blind' tests.

[zmf]

Originally Posted by Alan Carruth

That's the whole reason we need to rely on 'blind' tests.

Alan's mention of the Leonardo Project prompted me to review some of it's results. The main purpose was to test preferences for tropical and alternative non-tropical tonewoods. Here's one test if you're interested:

https://sites.google.com/site/leonar...h-report-lgrp1

Some conclusions were that "blind" players were much more consistent in their preference for particular guitars than "blind" listeners, and players had a similar preference for tropical and non-tropical tonewoods.

So apparently there's something different about actually playing a guitar, as opposed to listening to it. I was hoping to be reassured of that.

[The Bard Rocks]

Originally Posted by zmf

...

Some conclusions were that "blind" players were much more consistent in their preference for particular guitars than "blind" listeners, and players had a similar preference for tropical and non-tropical tonewoods.

So apparently there's something different about actually playing a guitar, as opposed to listening to it. I was hoping to be reassured of that.

Sure, you hear it from a very different perspective - playing as opposed to listening.

[koolimy]

Originally Posted by zmf

Alan's mention of the Leonardo Project prompted me to review some of it's results. The main purpose was to test preferences for tropical and alternative non-tropical tonewoods. Here's one test if you're interested:

https://sites.google.com/site/leonar...h-report-lgrp1

Some conclusions were that "blind" players were much more consistent in their preference for particular guitars than "blind" listeners, and players had a similar preference for tropical and non-tropical tonewoods.

So apparently there's something different about actually playing a guitar, as opposed to listening to it. I was hoping to be reassured of that.

That kinda supports my hypothesis that we need all our senses to actually perceive minute differences!

Of course the sad thing about those results is that bias/prejudice seems to be the single most important factor in determining ones preference for tropical/non-tropical woods.

[FingahPickah]

Pretty wood is pretty. Tone and playability is more or less everything.

As a player since the seventies, I’ve heard and/or played many dozens of guitars and until a very recent few years, “species” of wood seemed to draw less attention or drive instrument purchase choices.

I know some great players with some great instruments who couldn’t tell you what “species” of spruce, etc they have.

To clarify, I do, in fact appreciate this and other threads on the subject. It supports ideas like:
that to many of us (maybe most) may prefer one guitar over another with the same specs. And quality construction using time tested, properly prepared, fitted and finished tone woods may be more critical to the resulting product. And then there’s the least controllable variable known as the player.
I have Sitka, Adirondack and Engelmann each of my (keeper) guitars suits me tonally very well.

[varve]

Originally Posted by Alan Carruth

An interesting take.

From my perspective, as a luthier who measures the properties of the wood I use, cedar and spruce differ in two ways, usually. Although there is a wide range of variation in properties within any species, and a lot of overlap between species, generally WRC is less dense than most spruces. What's interesting there is that if you choose pieces with the same density, they will tend to have the same stiffness along the grain at a given thickness. This tends to hold for all soft woods, regardless of species.

Where spruce and WRC differ most consistently is in their damping: you will seldom find a piece of cedar with damping as high as most spruce. Although low damping (a 'clear' tap tone with a long 'ring') is generally considered desirable, it's hard to say exactly how it affects the sound of the guitar. It's distressingly easy to make a bad guitar out of good wood, and part of that is the ease with which one can add damping to the structure by being careless in design, construction, or finishing.

So, for me, cedar (and redwood, which shares similar damping characteristics) are in one class, and spruce in another. I have a lot of trouble with the sort of wine-tasting language I see on line about different kinds of spruce. It's not just species that are compared, but local populations within a species: 'Italian' vs 'Swiss' spruce, and so on. So far I have been unable to measure any systematic differences between spruce species, once you control for density: spruce all looks like spruce. Maybe I just haven't figured out what to measure yet.

I sort of agree, Alan. We've measured thousands of pieces of spruce for Young's Modulus, density, and damping, under standardized conditions and 8% equilibrium moisture content, and we DO see generalized differences between Lutz, Sitka, and Adirondack as shown in this graph, which is a representative subset of the data... but the tremendous variability shown here underscores your point about the importance of measuring each piece, and incorporating that information into your build. You can only predict so much, if all you know is the species name. Adirondack will TEND to be dense, but there is huge variability in stiffness (these samples are a mix of Boucher wood and Hampton Brothers wood, BTW). Lutz will TEND to be light and stiff, with a smaller range of variability, but there are exceptions, and Sitka...Sitka is all over the place. By measuring these properties, for each piece of wood, we can take advantage of the tremendous diversity nature offers, instead of being stumped by it.


https://www.flickr.com/photos/188914...posted-public/

Cheers, Dave Olson
Pacific Rim Tonewoods

[mcduffnw]

[QUOTE=varve;7220457]I sort of agree, Alan. We've measured thousands of pieces of spruce for Young's Modulus, density, and damping, under standardized conditions and 8% equilibrium moisture content, and we DO see generalized differences between Lutz, Sitka, and Adirondack as shown in this graph, which is a representative subset of the data... but the tremendous variability shown here underscores your point about the importance of measuring each piece, and incorporating that information into your build. You can only predict so much, if all you know is the species name. Adirondack will TEND to be dense, but there is huge variability in stiffness (these samples are a mix of Boucher wood and Hampton Brothers wood, BTW). Lutz will TEND to be light and stiff, with a smaller range of variability, but there are exceptions, and Sitka...Sitka is all over the place. By measuring these properties, for each piece of wood, we can take advantage of the tremendous diversity nature offers, instead of being stumped by it.



So Dave, have you folks been able to make any forms of consistent correlation between stiffness and density measurements of a given spruce species top wood set and basic tonal properties of that set, and if so, was there or is there any consistency to it, or is it still all over the map?...and can you apply that to each species of spruce, with each species of spruce having a basic tone "footprint" at given size, density, and stiffness measurements?



duff
Be A Player...Not A Polisher

[zmf]

Originally Posted by The Bard Rocks

Sure, you hear it from a very different perspective - playing as opposed to listening.

Don't understand your point. Or maybe I'm not clear on what you mean by "perspective".

One is sitting in front of the guitar, and one is sitting behind. Yet the one sitting in front has more difficulty knowing it's the same guitar is being played twice, while the player knows much more often.

Perhaps, as koolimy suggested, the player is simply getting more information about the guitar.

[ewalling]

Originally Posted by FingahPickah

I know some great players with some great instruments who couldn’t tell you what “species” of spruce, etc they have.

Nit just great players. I think the whole tonewood fixation spread with internet forums. I bought a 000 cutaway in 1988 that was made by luthier John Hullah. I once called Hullah and took the guitar for a tune up with him around a year after buying it. It was a nice guitar, and I played it a lot, but I had no idea what woods it was made from until 2007 when I joined AGF and heard everyone banging on incessantly about wood types. I then found out that my guitar was, in fact, made out of cedar and mahogany. I also remember feeling just a whiff of disappointment that the mahogany was not walnut. 'Walnut' sounded prettier!

[donlyn]

Guitar woods? Bah humbug!

Originally Posted by brianmay

Didn't realise bah humbug was a wood . . . do you know its Latin name?

"cacas".

De gustibus non disputandum.

Bene et ludere bene,

Don
.

[k_russell]

Originally Posted by redir

Hmmm, I didn't know Jerry Garcia played a classical guitar.

Gerry Garcia, yes. Jerry Garcia, probably not.

[Alan Carruth]

duff asked:
"...have you folks been able to make any forms of consistent correlation between stiffness and density measurements..."


I have not measured as many tops as Dave has, but I've done enough to feel that I've gotten consistent results.

What I measure for 'stiffness' is actually the Young's modulus of the wood: how hard it is to stretch a piece of a given size. This differs according to th grain direction, of course, and is generally much higher along the grain than across. Generally speaking the Young's modulus provides most of the restoring force when you bend a piece of wood: one surface has to stretch and the other gets compressed. The thickness of the piece makes a difference, of course, but, in general, the Young's modulus predicts the bending stiffness of a piece of material well at a given thickness.

As it turns out, for softwoods the Young's modulus along the grain tracks the density pretty closely, especially when you consider that we're talking about a natural material here. In my tests about 2/3 of the samples I've measured have been within 10% of the Young's modulus along the grain that would be predicted on the basis of density. As far as I can tell, from measuring samples of a dozen or more different softwoods, all of the softwoods tend to fall on the same line. White pine works just like Red spruce in this regard.

The main things that throw that off are the ratio of hard latewood to softer early wood, and runout. Latewood adds stiffness, but it adds density even faster, to the ratio of Young's modulus (E) over density goes down when the latewood lines are heavier. Run out, of course, comes from the fibers in the wood not being parallel to the surface, and this reduces the E value. Note that grain count per se does not seem to be predictive.

Cross grain stiffness varies all over the place. It's mostly related, so far I can tell, to how well quartered the piece is. This, in turn, is a function of the stucture of thwe wood: the cells looklike little rectangular boxes if you slice along the end grain. When the wood is perfectly quartered the sides of the boxes have to get compressed/stretched, but as you go off quarter the boxes can deform into parallelograms, with much less effort. Hardwods tend to have more rounded cells, along with some other differences, so they don't lose cross grain stiffness as fast when cut off quarter. In both hard and soft woods the medullary rays can add a bit of cross stiffness, since they're bundles of cells running out along the radius of the tree.

Again, Dave has lots more data than I do, and may be able to refine this.

[varve]

Originally Posted by Alan Carruth

duff asked:
"...have you folks been able to make any forms of consistent correlation between stiffness and density measurements..."


I have not measured as many tops as Dave has, but I've done enough to feel that I've gotten consistent results.

What I measure for 'stiffness' is actually the Young's modulus of the wood: how hard it is to stretch a piece of a given size. This differs according to th grain direction, of course, and is generally much higher along the grain than across. Generally speaking the Young's modulus provides most of the restoring force when you bend a piece of wood: one surface has to stretch and the other gets compressed. The thickness of the piece makes a difference, of course, but, in general, the Young's modulus predicts the bending stiffness of a piece of material well at a given thickness.

As it turns out, for softwoods the Young's modulus along the grain tracks the density pretty closely, especially when you consider that we're talking about a natural material here. In my tests about 2/3 of the samples I've measured have been within 10% of the Young's modulus along the grain that would be predicted on the basis of density. As far as I can tell, from measuring samples of a dozen or more different softwoods, all of the softwoods tend to fall on the same line. White pine works just like Red spruce in this regard.

The main things that throw that off are the ratio of hard latewood to softer early wood, and runout. Latewood adds stiffness, but it adds density even faster, to the ratio of Young's modulus (E) over density goes down when the latewood lines are heavier. Run out, of course, comes from the fibers in the wood not being parallel to the surface, and this reduces the E value. Note that grain count per se does not seem to be predictive.

Cross grain stiffness varies all over the place. It's mostly related, so far I can tell, to how well quartered the piece is. This, in turn, is a function of the stucture of thwe wood: the cells looklike little rectangular boxes if you slice along the end grain. When the wood is perfectly quartered the sides of the boxes have to get compressed/stretched, but as you go off quarter the boxes can deform into parallelograms, with much less effort. Hardwods tend to have more rounded cells, along with some other differences, so they don't lose cross grain stiffness as fast when cut off quarter. In both hard and soft woods the medullary rays can add a bit of cross stiffness, since they're bundles of cells running out along the radius of the tree.

Again, Dave has lots more data than I do, and may be able to refine this.

This is great info, Alan, thank you - clearly explained as usual with your posts, which I always enjoy reading! Duff asks another great question in his earlier post - for a given design, is density and stiffness (Longitudinal Young's Modulus) important to the resulting tonal quality of the instrument? Our testing suggests that its very, very important. For those who take the Fretboard Journal, there is a readable summary of the first phase of our research in Issue 48 (starting on p 74), and I put up a searchable summary of this sometime ago that I won't repeat in the interests of my time (I'm typing this between ear surgeries today!). Or you can PM me for info.

The next phase of our research, now completed, examines another property that Alan brought up, damping, or the internal friction of the wood as it is compelled to vibrate. Low damping wood tends to ring when it is struck, and is at least a part of what we listen for when we do "tap testing". Again, hugely important for sound quality, in a fairly predictable way. With each experiment we do, using both listening tests and playing tests, the instruments with lower damping top wood are consistently preferred in terms of tonal quality.

back to work, Olson!

[Andyrondack]

Originally Posted by zmf

Alan's mention of the Leonardo Project prompted me to review some of it's results. The main purpose was to test preferences for tropical and alternative non-tropical tonewoods. Here's one test if you're interested:

https://sites.google.com/site/leonar...h-report-lgrp1

Some conclusions were that "blind" players were much more consistent in their preference for particular guitars than "blind" listeners, and players had a similar preference for tropical and non-tropical tonewoods.

So apparently there's something different about actually playing a guitar, as opposed to listening to it. I was hoping to be reassured of that.

Something that puzzles me about the results of these tests from the listeners perspective is this.
When they can see the guitars being played why would listeners say they prefer the sound of guitars made from tropical hardwoods ? Most people with no specialist interest would not be able to tell one wood from another, and if they could due to some other interest then they would be most unlikely to know that rosewood or mahogany is traditionally the most used wood for back and sides.
If listeners are making their choice heavily influenced by visual aesthetics then why should attractive looking guitars using birds eye maple, walnut, myrtle and others be rejected in favour of the usual mahogany/ rosewood?