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  #46  
Old 01-17-2019, 02:29 AM
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colins colins is offline
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Quote:
Originally Posted by ruby50 View Post
I have limited experience but am amazed at the tap of Osage Orange. It sounds like a piece of of steel. It is that bright yellow when fresh, but inside of a year it is toned down to a lovely honey color. I have built 2 in this wood and had no trouble finding good stuff. Here is a 13" guitar freshly sanded and finished, with a mahogany neck:

https://www.flickr.com/photos/ruby16...7641029319394/

And less than a year later:

https://www.flickr.com/photos/ruby16...7641029319394/

Ed
Thanks Ed, those are really interesting pics.

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Originally Posted by Alan Carruth View Post
..At any rate, if I were looking for the closest thing to the sound of BRW without the CITES/Lacey issues I'd go for Osage.
Thanks Alan. Do you have comments as to the differences/similarities between osage orange and wenge?

Col
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  #47  
Old 01-17-2019, 07:55 AM
psychojohn psychojohn is offline
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Originally Posted by John Arnold View Post
I have played too many guitars with slab cut or other less than straight-grained Brazilian RW that sounded stellar. And checking tap tones of wood sets blindfolded has taught me that there is little or no correlation between these aspects and the actual sound produced.
You also mention tight grain, like it makes a consistent difference. I have not found that to be an 'etched in stone' rule, either.
I am not saying that straight grain is not preferred, both by Martin and many enlightened luthiers (me included). But like I said before, that is because it is both easier to build with and is less likely to warp and crack, particularly if treated badly. That does not automatically translate to better sound, however.

Very fascinating ! the things we think we know and understand that turn out not to be the case. Looks like it's time for me to revise that mental template.
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  #48  
Old 01-17-2019, 02:35 PM
Alan Carruth Alan Carruth is offline
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I've never worked with wenge: the local guys that have, have been so unhappy with the way it cracks that I've steered clear. I'm also not much into the 'magic wood' meme. Really big differences in the properties might translate into differences in tone (there are some who question even that based on data): I'd expect a soft, light mahogany to sound somewhat different from a dense and hard piece of BRW, but as between wenge, osage, and BRW...? I suspect that's going to be more on the luthier and the build. I've tried to make 'matched' guitars that sound the same using 'identical' wood and the tightest quality controls I could, and failed. Would two guitars with very similar wood, built with equally careful controls, sound any more different? I'm not sure.
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  #49  
Old 01-17-2019, 09:10 PM
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The lumberyard I buy from had a pallet of Wenge shorts (4/4 wood) cut at every angle from flat sawn to full quartered. Given the same size of board the difference of cut did not change the ringing quality between different cuts.
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  #50  
Old 01-18-2019, 01:06 PM
Alan Carruth Alan Carruth is offline
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Ring angle, how well quartered the wood is, should not make any difference in the damping, which is what determines how a piece rings when tapped. What it does change is the cross grain stiffness, particularly in soft woods, and the stability of the piece. Generally speaking wood shrinks and swell more with changes in humidity 'tangentially' (parallel to the surface of the log) than it does 'radially'. One outcome of this is to cause it to cup across the grain when the ring angle changes as you go across the piece. Well quartered wood will have the rings at 90 degrees to the surface all the way across, which produces the least amount of cross grain shrinkage and the greatest stability. A 'perfectly' flat cut piece, with the ring lines exactly parallel to the surface all the way across should also be pretty stable, in terms of cupping. The problem is that the only way to get a piece like that is to start with a tree of infinite diameter. There's only one of those in the universe, and it would take forever to cut it down. Flat cut wood also shrinks more than quartered, and it is not as resistant to splitting as quartered wood, owing to the orientation of the medullary rays.

The 'best' orientation to avoid splitting is probably skew cut; with the ring lines at a 45 degree angle to the surface. On soft woods this will have the lowest possible cross gain stiffness, but the difference is not so great with hardwoods, and may be negligible depending on the species. If I had to make a wenge guitar I'd try to find skew cut wood, with the least amount of variation in the ring angle I could find, for the back. It would be difficult to tell looking at it that it was not quartered, and I'd trust it more.
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  #51  
Old 01-18-2019, 06:05 PM
SCVJ SCVJ is offline
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This is off the OP's question, but this occurred to me as I read the posts about the excellent tap tone of the various woods being discussed.

Would any of them be suitable/desirable as top woods? I'm not a luthier, but have spent many hours reading posts about guitar building and haven't seen an explanation of why spruce, cedar, mahogany and koa (?) are just about all that are used for tops. If mahogany makes a good top, why not rosewood, locust, wenge, etc.

I realize that spruce and cedar are softwoods, but are they not suitable for back/sides, which seem to always be some species of hardwood. The top, after all, is where the bridge with all its tension is attached. Well-braced and backed with a tough plate, of course. The neck, also well reinforced, is attached at the "side".

This probably seems like a dumb question to those who build, but an answer or reference to one would be greatly appreciated.
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  #52  
Old 01-18-2019, 06:31 PM
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The heavier the wood the more energy it needs to get it to produce the same volume. The midweight weight woods like mahogany and walnut can make for an acceptable top. I would like to make a guitar with a maple top one day. Along with the maple a walnut back and cherry neck might look good. I am guessing the guitar would have more of a fundamental sound.
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  #53  
Old 01-18-2019, 06:53 PM
John Arnold John Arnold is offline
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Quote:
What it does change is the cross grain stiffness, particularly in soft woods
Hardwoods are fundamentally different. The reason cross grain stiffness varies in softwoods is because of the rectangular cell structure. A slight angle of the grain alows the cells to distort into parallelograms when the wood is flexed. Hardwoods have cells that are basically circular, so the cross grain stiffness is not materially affected by the cut.
Quote:
If mahogany makes a good top, why not rosewood, locust, wenge, etc.
I have seen plenty of attempts to use dense woods for soundboards, and they all fail, particularly when it comes to volume.
The important qualities of a soundboard are stiff and light. While some hardwoods like locust or rosewood have similar stiffness/density ratios as spruce, being heavier, the top itself cannot have the same high stiffness/weight ratio.
OTOH, you can use softwoods for the back and sides.....you just won't get the characteristic 'rosewood sound' that comes from a dense, hard surface.
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  #54  
Old 01-19-2019, 03:33 PM
Alan Carruth Alan Carruth is offline
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Think of it this way: there's not much horsepower in a plucked string. If you want to make a car with a small engine, and you need to have good acceleration and top speed, you need to keep it light. Acceleration in a car corresponds with high frequency output in a guitar, and top speed is like output power.

The most important parameter in the top is the relationship between the density and the Young's modulus along the grain. Young's modulus (designated as E) is a measure of potential stiffness: two things with the same shape and the the same E value will have the same stiffness at a given thickness. There are fairly simple ways to measure the E values of materials to fair accuracy. If you measure a bunch of samples of different kinds of woods you'll find that softwoods and hardwoods tend to have similar long-grain E values, but the hardwoods are normally denser. Sitka spruce often has about the same E value along the grain as Indian rosewood, but the rosewood will be as much as twice as dense. That means that a rosewood top will tend to weigh about twice as much for the same stiffness, assuming it's built in the same way as a spruce top.

What's most interesting is that for most softwood samples you can predict the long-grain E value reasonably well if you know the density: about 60% of the samples I've tested fall within 10% of the same line on the graph if you plot it out. The relationship is very nearly linear in the normal range of densities. Pieces where the latewood lines are narrow relative to the early wood tend to have lower density for a given E value, while heavy latewood lines tend to add weight without adding commensurate stiffness. Run out reduces the E value. As John Arnold points out, the main thing that seems to correlate with cross grain stiffness is the degree of quarter, due to the cell structure. If grain count (lines per inch) does make a difference it's not much of one, IMO.

Since stiffness in a top goes as the Young's modulus and the cube of the thickness, you can usually make a lighter top by using a low density piece of wood and making it a bit thicker. Thus a low density piece of hardwood, such as balsa, which tends to have a lower E value at a given density than softwood, can still make a light weight top simply because the density is so low to begin with. You might have to leave it twice as thick to get the stiffness up, but if the density is 4#/cubic foot, instead of 20#, it's still going to be pretty light. Not many hardwoods are enough lower in density than most softwoods for that to work out very often, but all woods vary, and you might find something that works.
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  #55  
Old 04-02-2019, 08:36 AM
psychojohn psychojohn is offline
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Quote:
Originally Posted by Alan Carruth View Post
Think of it this way: there's not much horsepower in a plucked string. If you want to make a car with a small engine, and you need to have good acceleration and top speed, you need to keep it light. Acceleration in a car corresponds with high frequency output in a guitar, and top speed is like output power.

The most important parameter in the top is the relationship between the density and the Young's modulus along the grain. Young's modulus (designated as E) is a measure of potential stiffness: two things with the same shape and the the same E value will have the same stiffness at a given thickness. There are fairly simple ways to measure the E values of materials to fair accuracy. If you measure a bunch of samples of different kinds of woods you'll find that softwoods and hardwoods tend to have similar long-grain E values, but the hardwoods are normally denser. Sitka spruce often has about the same E value along the grain as Indian rosewood, but the rosewood will be as much as twice as dense. That means that a rosewood top will tend to weigh about twice as much for the same stiffness, assuming it's built in the same way as a spruce top.

What's most interesting is that for most softwood samples you can predict the long-grain E value reasonably well if you know the density: about 60% of the samples I've tested fall within 10% of the same line on the graph if you plot it out. The relationship is very nearly linear in the normal range of densities. Pieces where the latewood lines are narrow relative to the early wood tend to have lower density for a given E value, while heavy latewood lines tend to add weight without adding commensurate stiffness. Run out reduces the E value. As John Arnold points out, the main thing that seems to correlate with cross grain stiffness is the degree of quarter, due to the cell structure. If grain count (lines per inch) does make a difference it's not much of one, IMO.

Since stiffness in a top goes as the Young's modulus and the cube of the thickness, you can usually make a lighter top by using a low density piece of wood and making it a bit thicker. Thus a low density piece of hardwood, such as balsa, which tends to have a lower E value at a given density than softwood, can still make a light weight top simply because the density is so low to begin with. You might have to leave it twice as thick to get the stiffness up, but if the density is 4#/cubic foot, instead of 20#, it's still going to be pretty light. Not many hardwoods are enough lower in density than most softwoods for that to work out very often, but all woods vary, and you might find something that works.
Wow ! Thanks for that info. You know, I've come to think of guitar building as an art. You just gave it a healthy dose of science for me ! Thanks ! John
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  #56  
Old 04-02-2019, 09:13 AM
varmonter varmonter is offline
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Back in the 30s all Birch guitars were common.
I have a parlor all birch from the early 30.
It sounds pretty good. I dont think its the luthiers
that perpetuate the brazilian myth as much as
it is us players. BRW not unlike a Tortoise shell plectrum,
have been engrained in our upbringing as being some
kind if grail. This inability to accept other woods as substitutes
Is a bit silly to me. But unlike diamonds which are
common and cheap ( except for us end users) BRW is endangered.
We will kill the last rhino for its horn. Because
we beleive nothing else will do. Even though we have viagra..
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  #57  
Old 04-02-2019, 09:55 AM
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Of all the picks Ive used tortoise sounds and plays the best. Not because of my expectations but my experience as I was not expecting any particular. A species of wood has characteristics that allow the maximum of any characteristic but may not be achieved by a builder or may be or close to its potential. All woods are not the same nor do they sound the same but woods of the same species sound and look more similar to each other than different species. A mahogany guitar and a braz guitar by the same builder will not sound the same because they have different potentials. You may like one or the other or oak but they will not sound the same. You may find an oak guitar and a rosewood guitar that sound very similar by different builders due to their ability to bring out the best in that particular species and set but that doesnt mean that all oak guitars will sound similar to all rosewood guitars.
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  #58  
Old 04-02-2019, 11:46 AM
varmonter varmonter is offline
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Yes but if martin had made their 1937 guitar
out of bubinga instead of brazilian. If no one
had ever thought of useing rosewood for b&s
we would all now be lusting after bubinga.
Furniture aside ( which is really why its endangered)
Bubinga would be on the cites list. And folks
would be saying that this new BRW is nice but its no Bubinga.
We hold BRW as The mother of all tonewoods. Honestly
Its a sound we've all subjectivly agreed on. Again That
Subjective sound could have just as easily been
Bubinga. Grails arent made they are socially agreed upon.
That this is the sound by which everything else is compared to.
Again I compare it to diamonds. Deberes created the mkt for diamonds.
The status quo ( a myth created by deberes) says this is what you give 25% of your salary
to make your girl happy. They aren't rare not even particular
pretty compared to an opal,emerald, ruby. Society says a diamond
it is.

Last edited by varmonter; 04-02-2019 at 11:58 AM.
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  #59  
Old 04-02-2019, 12:01 PM
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Actually Bubinga is on appendix II of CITES

And the reason why is not because it's a true rosewood, it isn't, but that it looks enough like one and as such has become exploited too. I can attest taht Bubinga makes a fine guitar too.
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  #60  
Old 04-02-2019, 12:04 PM
Alan Carruth Alan Carruth is offline
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mercy wrote:
"A species of wood has characteristics that allow the maximum of any characteristic but may not be achieved by a builder or may be or close to its potential. All woods are not the same nor do they sound the same but woods of the same species sound and look more similar to each other than different species."

A piece of wood has certain characteristics. Within any species there will be quite a range of characteristics, and there can be a lot of overlap between pieces of different species.

Each piece of wood offers possibilities and sets limits. It's up to the luthier to realize the possibilities and approach the limits.

Factories work to the average for any species. They build guitars with a range of sounds, depending, in part, on the range of properties in the different pieces of wood that are all worked to the same thickness. The average tone of their products reflects the average properties of the wood. Luthiers tend to work 'to the wood', and 'toward a sound'. They will alter the thickness and other things to take advantage of what a particular piece has to offer, to the furtherance of the sound they're trying to make. Most luthiers have a characteristic sound, which is displayed by all of the instruments they make to at least some extent. Specifying the species might help you get a factory guitar that sounds the way you want it to. In the case of a luthier, you look for the person who makes that sort of sound, and let them pick the wood.
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