Is There A Grain Of Truth?

[NursingDaBlues]

I recently A/B’d two new mandolins; same manufacturer, same model and style; same year; pretty identical set-ups. One had more bark; the other was a tad darker. Both nice sounds; just different. Made me think of other times when I’ve encountered differences in voice between the same models by other manufacturers.

So…

Somewhere along the way, I either read an article or saw a video about spruce tops on Martin Guitars. I seem to remember Dick Boak of CF Martin stating that Martin determined that placing the wide grain in the middle and the tight grain on the edges on mahogany guitars tended to add more bass response. On the other hand, placing the tight grain in the middle and wide grain on edges on rosewood guitars tended to add treble response.

Assuming that my memory in recalling this information is accurate, does something similar hold true for where you position the grain on maple-body mandolins with spruce tops? Just trying to find a rationale for markedly different sounding voices on the same model other than different tree, different luthier, different day-of-the-week that each was built, etc., etc.

[Joey Anchors]

First was there any real scientific tests done to prove Dick Boak's claims?

Personally I think it just comes down to how all the pieces of woods being used sounds together.

[JeffD]

I remember something about grain placement with guitars, but I don't remember the details. It doesn't sound implausible.

Just trying to find a rationale for markedly different sounding voices on the same model other than different tree, different luthier, different day-of-the-week that each was built, etc., etc.

Every piece of wood is different from every other piece of wood that has ever been.

A friend of mine makes violins. His violins have seen work in more than a few orchestras.

He told me that it is impossible for him, or anyone, to make two violins that sound exactly the same. (And he adds that if he ever managed it, it would be a total accidental confluence of factors that he could not have foreseen much less deliberately produced.)

That said, I know that there is a similarity in the sound of his fiddles, that has been reported by players and that sometimes I fancy even I can detect. (Probably wishful thinking.)

It might be possible to make identical sounding instruments with artificial materials whose properties can be controlled in all directions. But even then....

[Luna Pick]

First, I'm no luthier and defer to the pros, but I suspect it's more the variables you list, and variance, however slight, in how the tops were tuned and braced. The variables you list can be considerable when they occur in various combinations.

Re grain, my understanding is and observations have been that tighter grains in the middle under the bridge for strength, wider towards the edges to allow the tops to flex and respond to the playing, i.e. vibrate.

[fscotte]

Seems to be another one of those old luthier's tales.

[bratsche]

It might be possible to make identical sounding instruments with artificial materials whose properties can be controlled in all directions. But even then....

(But even then....) you have to consider the human element. Two random people playing the same instrument are very often capable of making it sound quite different. And two random pairs of ears hearing the same instrument played by the same person will perceive it differently. And so on.

bratsche

[Tobin]

Assuming that my memory in recalling this information is accurate, does something similar hold true for where you position the grain on maple-body mandolins with spruce tops?

I don't know if it would be similar to guitars, in terms of treble/bass response. But the answer in general is "yes", variations in wood grain thickness could have some effect on tonal response. I think that much is obvious. The cellular structure and density is different between tight grain and wide grain. It would seem to make sense that the stiffness would be affected between these different zones, which could affect how vibration waves travel through the sound board (and where they are in relation to braces, tone bars, edges, sound holes, bridges, etc.).

Demonstrating it, however, would likely be extremely difficult.

This thread, like so many others, will end up with Pavlovian-like calls for "double-blind studies!!!!!!!"

[Spruce]

Seems to be another one of those old luthier's tales.

Yep, it's all about the wood, and has nothing to do with the luthier whatsoever...

[JeffD]

My fiddle maker friend explained to me that to make two instruments sound the same you cannot do the same thing with each. That will guarantee a difference, because the wood is different. You would have to do with this wood here what will create a result that matches the result of what you did with that wood over there.

[fscotte]

I don't know if it would be similar to guitars, in terms of treble/bass response. But the answer in general is "yes", variations in wood grain thickness could have some effect on tonal response. I think that much is obvious. The cellular structure and density is different between tight grain and wide grain. It would seem to make sense that the stiffness would be affected between these different zones, which could affect how vibration waves travel through the sound board (and where they are in relation to braces, tone bars, edges, sound holes, bridges, etc.).

Demonstrating it, however, would likely be extremely difficult.

This thread, like so many others, will end up with Pavlovian-like calls for "double-blind studies!!!!!!!"

Sound waves do not travel through wood, so grain density doesn't apply to that notion. Stiffness and mass determine a great majority of the tonal response. Wide grain can be stiffer than close grain.

[Bill McCall]

Sound waves do not travel through wood, so grain density doesn't apply to that notion. Stiffness and mass determine a great majority of the tonal response. Wide grain can be stiffer than close grain.

I had no idea that wood was a perfect sound insulator. Learn something new every day.

[allenhopkins]

I had no idea that wood was a perfect sound insulator. Learn something new every day.

Yeah, wish I'd known that when the guy in the apartment below me, back in 1975 or so, put I Can See Clearly Now on infinite repeat for an entire afternoon. Must have found some non-wood material to transmit that bass line.

[Tobin]

Sound waves do not travel through wood, so grain density doesn't apply to that notion. Stiffness and mass determine a great majority of the tonal response. Wide grain can be stiffer than close grain.

Say what? Did you even read what I wrote when you quoted me?

I said vibration waves. Probably a poor choice of words, but the entire top plate vibrates. And vibration, by its very nature, is a wave. It travels through the wood.

I went on to say that density affects stiffness. You disagreed with me and said that stiffness and mass are more important. You do realize that density and mass are related, right? If one area of wood is more dense, that means it has more mass in the same volume as a less dense piece. Ergo, the density affects mass (and stiffness), which affects tone.

[fscotte]

Dave Cohen is missed in threads like this one. Visualizing sound waves traveling through wood is easy to think, but it doesn't happen that way. I recall a thread a while back where I mentioned that John Monteleone described sound waves as traveling from the bridge and coming to the tone bars. The tone bars then helped slow up the sound waves to even transmission of sound. It was pointed out that it just doesn't work that way.

Luthiers I found like to find a way to describe what works for them if it helps them build mandos. It certainly helps Monteleone no question. But sometimes, they are just old luthier's tales.

[fscotte]

Instead of getting into a scientific wrestling match, I'll just post one of Dr. Cohen's responses from a previous thread. The topic is easily searchable.

I've run out of patience and just hafta post something here. First, sound waves don't "travel" or "shuffle" through parts of an instrument to other parts of an instrument. The wave motion in instruments is much more analogous to standing waves than to traveling waves. The waveforms in strings don't travel through the bridge to the top plate, and etc. Each part of an instrument vibrates in its' own modes of motion, called normal modes of vibration, btw. What those string modes do is produce pulses of force, which are exerted on the top plate through the bridge. Each time the string near the bridge passes through zero amplitude (i.e., through its' equilibrium position), it exerts both a longitudinal force pulse which rocks the bridge slightly, and a normal or transverse force pulse which moves the bridge (and in turn the top plate) up and down. The sum of the force pulses from all of the string harmonics excites many different normal modes of motion in the top plate, back plate, and air cavity. Each of those modes of motion is characteristic only of the part that is undergoing the motion. Sound waves from the string(s) don't find their way into the top plate. The top plate has its own modes of motion; it does them only - no others. Now, to some extent, the motions from each part influence or "perturb" the motions from other parts, but that is a subtle effect, and has mostly to do with frequencies. The modes of motion of the top plate look substantially like the modes of a plate clamped at its' edges. You can see holographic images of those plate modes in my papers or in my chapter in the 2010 Rossing book.

[Charlieshafer]

I watched Dana Bourgeois voice a guitar top, and to do so, he took material in varying amounts off the bracing. Tapping around, finding dead spots, or notes tomes that were too old compared to others, he went back and shaved braces. Every top receives this procedure, tapping away, shaving, until all the tones sound equal in volume. This makes more sense than the grain of the wood. As everyone has mentioned, every piece of wood is different anyway, so treating them all as equals doesn't make much sense.

[Mandoplumb]

Come on guys, what Tobin was talking about was the vibration of the top and how that affects the sound waves. If there is nothing to that why do we talk of kinds of wood in mandolin tops and how they are carved and how they are braced and etc

[fscotte]

A further quote from Dave Cohen in regards to the very thing we are discussing - grain width. Summary, it doesn't have much bearing on stiffness, density, or internal losses. In other words, grain count is most useful for aesthetics.

With regard to the tight grain/wide grain question, anecdotes have been presented by several people in this thread which disprove the hypothesis that grain count is a major factor in either the quality or the characteristics of a resulting instrument. Does it play some role? Posssibly, but as Spruce pointed out, there are too many variables to unscramble to say with any confidence exactly what that role is. Further, the importance of stiffness (actually Young's modulus), density, and internal damping ("Q") are large. If you test numerous samples of instrument wood (as Haines has done), along with keeping track of the grain count, you will find that there is little if any correlation between grain count and any trend in those properties. What matters most in instrument top plate wood is the ratio of a product of the parallel and perpendicular Young's moduli to the density (see Haines). You will find that there is no correlation between the grain count and that ratio. There are stiff and light pieces of wood with tight grain, and stiff and light pieces of wood with wide grain. Same thing with Q; samples of wood with low Q and wide grain, as well as samples of wood with low Q and tight grain, and so on. Build those various pieces of wood into instruments, and the properties will remain, despite differences in construction. The wide variation in properties with grain count insures that grain count by itself will not be a major factor in either the perceived quality of the instrument or specific characteristics. If you want something more, you are looking for tone fairies or wood sprites. I can't help you with that.

[Mark Gunter]

To the OP, one displaced Louisiana boy to another - you can see here a very small hint of the trouble you can stir up by writing about such things. There are all kinds of beliefs and biases that luthiers have from differing traditions and experiences, and there are scientists who study acoustics, and physical properties of instruments who are quick to point out that a lot of what is believed by folk who do not base all knowledge on the scientific method is hogwash.

The science can teach you alot. First, though, we have to consider that science doesn't have all the answers. There is a search for understanding hopefully divorced from rumor, wishful thinking, tradition and superstition - but the knowledge or understanding gained from scientific research is still very limited. There is no way to address every factor, or even to know if we are asking just the right questions, making the best and most accurate tests, or focusing on the most important aspects. And for all the great knowledge and understanding that science has brought us, there still is no scientist who can tell you that the way to get the sound that you want from an instrument is to build it just so with just these materials.

Martin guitars are legendary for their success in guitardom by virtue of the improvements the company made to the guitar, the sound so widely endorsed from most of the guitars, and the marketing they've employed. Any of the successful Martin luthiers will have worked within a tradition, made some experimentation, gotten a lot of mileage (experience) in guitar lutherie and will have strong opinions about how things work with the instrument whether or not his beliefs about the why run contrary to scientific findings.

I'm only writing the above for the OP, to say that these types of threads are pretty common here. There is really no consensus on the beliefs of luthiers, no matter how great the luthier's reputation.

[Bill McCall]

But there is a consensus and scientific evidence that sound travels through gases (air), liquids (water) and solids (steel and instrument tops). That is a quite different statement than the notion that a sound wave travels (or doesn't travel) down the bridge and across the top of an instrument, which I believe is the statement addressed in the first Dr Cohen quote.

There isn't much in the physics or acoustics of instruments that's as simple as we might want to hope, except maybe that the more energy you put into the string, the louder the sound. Your pleasantness in hearing may vary.

[Mark Gunter]

Bill, there is consensus on how sound travels, is generated, etc.; there is general consensus on wave theory, i.e. standing waves, traveling waves, etc. The OP didn't get into all that, his question was about a Martin guitar luthier's opinion regarding grain patterns on guitar tops, and the relevance of that luthier's opinion as applied to mandolin construction by analogy.

I guess my point is that he probably didn't realize the volume of the can of worms such a question would open up here at the cafe. There is no consensus among luthiers about grain patterns for one, and for two, scientific evidence seems to negate what the Martin luthier propounded. That's not to say that the Martin luthier doesn't know how to build a great sounding guitar.

[Mark Gunter]

Yep, it's all about the wood, and has nothing to do with the luthier whatsoever...

A bit of sarcasm I think, and well put. No matter how science goes about explaining everything, there is definitely some "magic" having to do with the skill, instinct, craftsmanship and mileage of the luthier - and there is definitely some "magic" brought forth by the end user. If anyone balks at the term "magic" replace it with something else; the work of the luthier and of the musician make more difference in the end result than the materials.

[Ivan Kelsall]

JeffD - Many thanks for pointing out the obvious to us,& i'm not being sarcastic - many of us overlook exactly that !!.

I'm pretty sure that most luthiers, as does Jeff's Violin maker friend, say the same thing. Even making 2 'whatevers' from the same batch of wood,to the same dimensions as identically as you possibly can,will result in 2 (or more) instruments that will not sound 'exactly the same'. Their may be a family ressemblance,but that's as far as it goes. No 2 (or more) pieces of wood are identical & unless you could make all the wooden 'bits' identical to each other,then there will be differences - & most of us understand this.

I'll put a notion forward that i've been discussing with a few Cafe member e-mail friends in the US, to do with the 'arch' of a mandolin top. I suppose i should really put this in the builder's section but - my Weber "Fern's" top has more 'arch' to it than my Lebeda or Ellis. It's not huge,but it is there. The Weber also has a brighter tone than the Lebeda or Ellis -so,i'm supposing that as a result,the Weber top could be 'stiffer' & so produce a brighter tone - would that be correct,or am i barking up the wrong piece of top wood ?. I was wondering if any builders control (if that's the right word) the tone of their instruments by adjusting 'how much arch' their tops (backs ?) have & not just by the way they're graduated.

I had a look at my 3 mandolins yesterday & the Ellis & Lebeda seem very much the same,the Weber has a tad more 'hump' in it - is there any sense to this ?,
Ivan

[NursingDaBlues]

Hmmm…

Note To Self: Thank the Good Lord for the materials that go into the production of beautiful instruments. Be sure to thank the men and women who possess the knowledge and creativity to turn those materials into beautiful instruments. Play only those instruments that make me smile regardless of how they’re put together.

Note To Self #2: Don’t ask questions that can evolve into a hockey match.

[HoGo]

No one mentioned that there can be striking difference of both density and stiffness across one piece of wood. I remember someone cut a guitar top into strips 1" or so wide and measured density and stiffness of each and got quite random numbers... When you measure whole top you get more or less composite (or average) of the numbers but your piece can be denser or stiffer at any of the places (center or edges or somewhere in between...) so changing ceter to edges likely will produce different sounding instrument but it is impossible to tell which way the difference will go unless you measure somehow densities and stifnesses all across the wood...