Myth's and Science (Full Version)

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Patrick -> Myth's and Science (Jul. 12 2010 21:23:42)

Thought the builders (and non) might find some of this guys ideas interesting.

Click on each heading and it takes you to another page with more info.

http://www.liutaiomottola.com/myth.htm



kovachian -> RE: Myth's and Science (Jul. 13 2010 0:45:46)

More than I'll ever need to know, but interesting nonetheless. Tank yee for the link.



estebanana -> RE: Myth's and Science (Jul. 13 2010 1:20:17)

He's interesting and I like his writing, I can relate to being a debunker.

You might even call me an Archie Debunker.

Mottola is cool because he cites Sun Ra as an influence on this choice of title for his essay. Sun Ra was a bad MuthaF, badder than Shaft. IMO. :)



krichards -> RE: Myth's and Science (Jul. 13 2010 7:58:02)

There have been lengthy debates on some of these myths here on the forum in the past.

So next time one of these myths crops up we can at least refer to this link and get a balanced summary of the main research.

really useful link thanks.

Please remind us of it next time something contentious turns up here



XXX -> RE: Myth's and Science (Jul. 13 2010 9:19:59)

quote:

The tension isn't identical mind you, but it is very close across strings in a set.


Daddario:
J4501 E 6.94
J4502 B 5.26

Difference: increase of 32% tension from B to E. And it doesnt say whether the smaller surface is included in the data, so it could be even more than 32%.

In the end its just a summary of his opinion, not science (at least i dont see any), but for documentation purposes it is good to have the main debatable points written in one page. Generally i think, that people who question the senses of musicians (or humans in general) on "what sounds good" should *logically* not spend any money on expensive or average guitars. If one really thinks that the perception is so vague that it is impossible to judge whether a guitar sounds good or not (for example in the broken in vs new debate) he can likewise buy the cheapest available guitar.



aarongreen -> RE: Myth's and Science (Jul. 13 2010 12:53:59)

Hi Guys,
I know RM, he's a good dude, an engineer I believe by his first profession. He assisted me when I wrote the pegs article for the GAL some years ago. Scientific proofs have to be taken within the context of the experiments that were conducted. There are way too many variables that exist in the real world so things get broken down into more manageable bites and within that context you can at least get part of the picture....which is not the whole picture. It's like a flashlight in the dark as it were.

I looked at his string tension page and my first thought is that he was using two fixed points to hold the string. Guitars vibrate, necks vibrate which makes them not quite as fixed as what I saw in the picture. However in the context of his experiment, I agree that the length of the string is not going to be a contributing factor to the "pulsasion".......in and of itself.



Patrick -> RE: Myth's and Science (Jul. 13 2010 17:37:40)

Aaron,

One other area he comments on that I thought was interesting is the "no treble-bass side" of a guitar. The guitars you have built for me have a transverse bar (I think that's what it's called), giving a smaller surface area on the treble side, versus the bass. From what he says you could string these guitars as left hand and they would sound exactly the same. What's your take on this?



Patrick -> RE: Myth's and Science (Jul. 13 2010 17:42:19)

quote:

I looked at his string tension page and my first thought is that he was using two fixed points to hold the string. Guitars vibrate, necks vibrate which makes them not quite as fixed as what I saw in the picture. However in the context of his experiment, I agree that the length of the string is not going to be a contributing factor to the "pulsasion".......in and of itself.


The other thing of interest is his thoughts that the string length goes all the way back to the tie point on the roller, as the string can stretch all the way back to that point. Makes sense.



Ron.M -> RE: Myth's and Science (Jul. 13 2010 18:42:49)

quote:

The other thing of interest is his thoughts that the string length goes all the way back to the tie point on the roller, as the string can stretch all the way back to that point. Makes sense.


Yeah Pat...

And the point I was trying to make in the "string tension" argument last year was that strings are NOT on rollers...but that the nut exercises considerable friction, especially to a momentary deflection force.
This is not the same as looking at things like the tension in long control cables (over rollers) versus shorter control cables as in manually operated aircraft flaps and elevators in slow, steady increases or decreases in tension etc..

http://www.foroflamenco.com/tm.asp?m=118746&mpage=1&p=&tmode=1&smode=1&key=


He states exactly the same thing...that it is NOT the same...as in the control cable example.

A guitar nut is NOT a low friction roller.

Also the "roller" and "string stretching right back to the machine head" theory is blown right out of the water once you introduce a capo into the equation.

Two equal strings stretched over a same fixed scale length and at the same pitch, have the SAME tension and have the SAME stiffness (or resistance to momentary deflection.)

cheers,

Ron



Ramon Amira -> RE: Myth's and Science (Jul. 13 2010 19:37:52)

quote:

The other thing of interest is his thoughts that the string length goes all the way back to the tie point on the roller, as the string can stretch all the way back to that point. Makes sense.


For whatever it may contribute to this - Manuel Reyes said "Sound starts at the hueso cejilla" - the nut.



Ron.M -> RE: Myth's and Science (Jul. 13 2010 19:46:23)

quote:

Manuel Reyes said "Sound starts at the hueso cejilla" - the nut.


And James Brown said.."Take it to the bridge..." [:D]

cheers,

Ron



estebanana -> RE: Myth's and Science (Jul. 13 2010 21:39:14)

I made two guitars where I reversed the lower transverse bar to make the treble side more open and close the bass side. You know how you do that? You forget that the plan is a mirror image and you build the top inside up. then when you flip the top over the braces are backwards.

I wonder how many guitars makers have made that mistake? Or will admit to it. Lot's of guitar makers like to act like they are perfect all the time and it's .........well not true. You just have to rework your mistakes and your skill comes in by making it look like you nailed it the first time around.

Anyway I did that once by mistake and once by intention. Each guitar sounded good. But one was much, much better than the other. Why? Because they were built eight years apart and I had gotten better in general over that time. It's curious to muse about the treble/ bass side effects of sanding under the top, but I bet there a lot of things guitar makers do that will work not because they intend to make a design based on logic, but because they can make anything work by intuition.

I prefer to discuss conceptual and historical issues over things that are tactile and based in muscle memory and intuition. Each builder develops a sense for that stuff and it's really hard to talk about. It's more of an internal, non verbal logic. If each person trusts themselves that stuff naturally develops.

The short essay I like the best is the one about the violin scroll. it show just how many different kinds if spirals and volutes there are.



Andy Culpepper -> RE: Myth's and Science (Jul. 13 2010 22:18:51)

Aaron may correct me but the way I understand the angled transverse bar or any asymmetrical top construction, is basically that it's supposed to pump more sound out front instead of just having it churning around the guitar.
When the bridge is rocking side to side in a dipole fashion, if the top is totally symmetrical, each side is sucking in and pushing out air at the same rate. having an asymmetrical top might cause some or all notes to project out more away from the player....



Patrick -> RE: Myth's and Science (Jul. 13 2010 22:29:20)

quote:

I made two guitars where I reversed the lower transverse bar to make the treble side more open and close the bass side. You know how you do that? You forget that the plan is a mirror image and you build the top inside up. then when you flip the top over the braces are backwards.
[:D][8D]



aarongreen -> RE: Myth's and Science (Jul. 14 2010 4:13:32)

Hi Pat and Greg,

In talking about top design you have to consider that a plate will vibrate in a multitude of ways through out a set frequency spectrum. Anything you do to the plate will affect how (and where) those vibrational patterns form, relate to each other and how efficient they are. Those are called modes for sake of having a term. Anyways the lower frequency modes are the ones we have the most independant control over, through how stiff the bracing is and how well matched it is to the top. Once the guitar is assembled you can work with the top thickness and graduations if you want to bring things into focus. Working the interior braces is also a method that can be employed, which is what Tom Blackshear is doing for his fine tuning. Everyone decides for themselves what needs to be done in the moment.

As you go up in frequency you quickly lose the ability to do anything to one mode without drastically affecting all the others. The lowest wood mode (as opposed to air mode) forms a ring shape.....called the ring mode. That is when the top is pumping in and out in it's most straight forward fashion. No matter how you brace your top that mode will be there and that's what it will be doing. The next in line is the top dipole and once again, it does what it does. Both can be a bit asymmetric, it's true, but I have never had a top do that where I felt it was tuned as well as it should be.

What I think Old Greg is referring to is about how the top interacts with the air modes in the guitar. The top vibrates, causes the air to vibrate, (how and at what frequency is determined by it's volume, shape, size, depth of the guitar. the compliance of the sides, top and back and the size and location of the soundhole,) Anyways then the back vibrates, which in turn moves the air ...on down the line. Losses are inevitable but how well "tuned' the system is determines to what degree those losses are and where they manifest. So all of this is but to say that there are many variables that determine how efficient a guitar is. I have yet to find a direct correlation between the success of a guitar and whether or not I use an asymmetric or symmetric pattern. I build both depending on what I want the character of the guitar to be and the wood I have to work with.

In terms of the angled waist brace......Anything you do to a guitar top, symmetric or asymmetric will have an affect or more to the point, will be part of the recipe for why a specific guitar sounds the way it does. Whatever the guitar is doing, the whole guitar is doing it. I don't believe that a guitar will sound different if you were to switch the strings around. Feel different, most definitely but not sound different. The only reason I would expect it to feel different is that necks are often asymmetric, but then how many of us can play both righty and lefty?

Hope this helps!
aaron



krichards -> RE: Myth's and Science (Jul. 14 2010 8:00:50)

quote:

One other area he comments on that I thought was interesting is the "no treble-bass side" of a guitar.


It seems to me that the important thing is to have areas of thre soundboard with different stiffness and therefore these areas will repond strongly to different frequencies (they will have different resonant frequencies)
Of course, they are not separate areas, its a continuum.
But it really should make little difference which side the stiffer, 'treble' areas are on. The only factor that might affect this is that the bass E is about 6cm away from the treble E so there might be a small difference?

My anecdote for what its worth:
I know a beautiful Manuel Bellido that is the wrong way round inside: a mirror image of what you would expect. Its a very good guitar as we expect from Bellido.
My guess is that it was made for a left hander and then set up for a right hander or maybe it was an experiment or maybe a mistake?
The point is you just wouldn't know till you looked inside.



estebanana -> RE: Myth's and Science (Jul. 14 2010 18:13:58)

Manuel Bellido experimented with putting the braces diagonally. Antonio Moya has one like that and it's the best guitar I've ever heard. (my taste). Moya told me that and then traced the direction of the braces on the top. It was a motivation for me to try new things that do not fit the common practice or when I realized you can make darned near anything work.

The classic move of the transverse brace toward the treble side, for example in Santos, serves to close the top off and make the "drum head" part of the top smaller. So here is the question: What happens when you make the top 'smaller' by cutting down the drum head area with an asymmetrical transverse bar, but keep the whole box the same size?

Do you think perhaps the idea is misinterpreted and what was really going on is that it's not a special treatment for trebles, but a way of getting at small top efficiency coupled with bigger box performance?



keith -> RE: Myth's and Science (Jul. 15 2010 0:26:56)

a question then about that transverse strut. as i understand it santos and ramirez use the transverse strut, located on the "treble" side to increase the treble (i guess to increase the frequency). if the transverse bar were on the "bass" side would the guitar, all things considered equal, produce a less treble response? a more bass response?

or have i sheepishly bought into the myth? if so, the wolf has enjoyed a nice meal. if not, then there is the question about making a "righty" guitar into a "lefty" guitar. the bass strings would be over the transverse strut. would the guitar produces less treble? more bass? if not, why add a transvere bar?



estebanana -> RE: Myth's and Science (Jul. 15 2010 2:09:01)

See what a can of worms it is? :)

Even though I really like the writing and the title of the Myth and Science essays, guitar making is not really about science vs. myth as strict binary opposition. It's more about common sense, everyday practice and personal observation.

The guitar is a whole system and breaking it down so you isolate one part without thinking going to effect other parts is, at least to me, a mistake. So I never really took it for granted that the slanted transverse bar is for treble enhancement and nothing more because I did not know Santos or Ramirez. When Santos and Ramirez are cited as saying the asymmetric transverse bar it's for the trebles it is received wisdom. How can you trust that? i have difficulty with received wisdom, which is different from myth. Myth implies something more outrageous like a violinist saying the build up of rosin around his bridge is making his tone better. ( yes I heard that form someone.)

Received wisdom says it is for the trebles, but if you start thinking about it there are other things that it could do. And lots of variables come into play, top thickness, brace size, plantilla width....and on and on. I can't say unequivocally it is for trebles, but I can say I look at the most basic guitar design, and think the transverse bar is for stopping the top at the waist and to strengthen the top from folding up. I ask the most basic questions first, before getting into the nitty gritty of modes and tap tones etc. and when I see the transverse brace being moved lower, I think, it's making the top smaller.

This is why I say I like a conceptual approach rather than an approach which starts with the minutae of whether or not you can tune it by shaving braces or other esoteric modifications. I think most guitar makers work this way, but something about bypassing these basics seems to often come up. Ervin Somogyi once told me talking about bracing is like talking about religion. That really makes sense to me because bracing and how you use it is so personal, like rasgeuados. So my effort is to not be specific in the beginning and work from the bigger general things I know to the details. Not details first. I'm kind of rambling, but I'm saying there are basic things to get like why we stop the top at the waist with a transverse bar and then after that understanding in place think about what happens to the whole structure when you move it.

Look at Fleta's brace layout, before we begin to think we can second guess his brace shaving, let's look at his overall architecture and establish some basic knowledge about it. He had a main transverse brace which bisects the top and then under that he added a second one which angles down on the treble side. If we move under the premise which Motolla brings up; many things are scientifically evident, like the idea that trebles don't manifest themselves in just one part of the top, yet if we in intuitively move the transverse brace down towards the trebles this can increase trebles. It is not about busting the science with intuition, it's about understanding we have manipulated a whole system. Maybe the trebles were effected as a byproduct of that structural change, but maybe several other things as well.

So with Fleta he has stopped the top at the waist and moved another bar down towards the trebles to make less surface area of fully active top. And he has that funny fat wide load trailer upper bout full of air. What was he up to? Was he using a smaller active top area to drive a bigger air column? I wish I knew. But we can think about it in terms of bigger picture structure first details second.



Ramon Amira -> RE: Myth's and Science (Jul. 15 2010 3:28:23)

quote:

guitar making is not really about science vs. myth as strict binary opposition. It's more about common sense, everyday practice and personal observation.


According to Jose Ramirez IIIs' own account of it, he decided early on that he wanted to not merely build a great guitar, but he wanted to know WHY it was great. So he said that he spent sixteen years studying physics, mathematics, acoustics, etc. and then spent years applying all that to his construction, making model after model utilizing all his theoretical knowledge. Finally after years of experimentation he arrived at his ultimate "scientifically" constructed guitar, which he was very happy with. To his astonishment he said it was almost identical to those made by his uncle Manuel fifty years before, made purely by instinct, intuition, and experience.

Ramon



Richard Jernigan -> RE: Myth's and Science (Jul. 15 2010 15:09:43)

quote:

According to Jose Ramirez IIIs' own account of it, he decided early on that he wanted to not merely build a great guitar, but he wanted to know WHY it was great. So he said that he spent sixteen years studying physics, mathematics, acoustics, etc. and then spent years applying all that to his construction, making model after model utilizing all his theoretical knowledge. Finally after years of experimentation he arrived at his ultimate "scientifically" constructed guitar, which he was very happy with. To his astonishment he said it was almost identical to those made by his uncle Manuel fifty years before, made purely by instinct, intuition, and experience.

Ramon


I have read Ramirez' book a few times in the original and in the English translation. I also spoke with him several times at the shop in Concepcion Jeronima while I bought instruments that I sold in the USA.

His 1a's, made famous by Segovia, differ in many important respects from the guitars of his great-uncle Manuel. The scale is longer, the body is larger, the bracing is different, the top is cedar on most of them. The two designs differ significantly, and the guitars sound different.

I have degrees in mathematics and physics. I had a successful career as an engineer for more than 40 years. I have played the guitar longer than that.

Jose III's excursions into mathematics and acoustics appeared to me to have little basis, and no strictly scientific support. He made no scientific measurements to support his theories, as does Al Carruth, for example.

Like most luthiers before and since, he tried his ideas by building guitars, or having them built by his very talented 'oficiales' like Contreras, Bernabe, Manzanero, Antonio Martinez and others. He arrived at a very successful design that made him wealthy. But I would contend that he operated like most luthiers of the past and present, by trial and error, not 'scientifically'. There is no fault in this. Even the most scientific of luthiers today, with all the benefits of modern measuring equipment and techniques, say that guitar making is an art, not science.

RNJ



aarongreen -> RE: Myth's and Science (Jul. 15 2010 16:20:23)

In my mind art and science are two sides of the same coin. And they are both mutually agreeable. In fact one serves to help verify the other. In practice that's not always the case. What you have then is one sidedness and in such cases the end result is not fully realized. So it's not perfect art or perfect science.



Richard Jernigan -> RE: Myth's and Science (Jul. 15 2010 18:09:05)

In saying "art not science" I was echoing some distinguished physicians I have known. While medicine has profited more by science than any of the non-scientific professions, with the possible exception of engineering, medicine still does not qualify as science in the minds of some of its most able practitioners.

In science, the ideal is to be able to say, "If A, then B" with no ifs, ands or buts. (Of course in quantum mechanics, "B" is often a statement of probabilities.) They tell me that in medicine, diagnosis and treatment sometimes proceed more from the experience and skill of the physician than from absolute scientific certainty. And there are conditions whose cause is unknown, but whose treatment is effective, as well as sizable areas of nearly complete lack of knowledge about either cause or treatment, though the symptoms have been known and described for decades, if not centuries.

I have read some of the most "scientific" luthiers who say the guitar is such a complex system that it is beyond the present capability of science to fully analyze it. Also I have read, "Science can distinguish good guitars from bad ones by measurement, but it can't distinguish good ones from great ones."

I agree with your far more expert opinion that luthiery can and does profit from science, but my observation has been that for most luthiers it is more of an art compared with, for example, engineering or medicine.

It's great to have such a range of expert players, aficionados and makers on this forum.

RNJ



Ramon Amira -> RE: Myth's and Science (Jul. 15 2010 20:44:47)

quote:


Jose III's excursions into mathematics and acoustics appeared to me to have little basis, and no strictly scientific support. He made no scientific measurements to support his theories, as does Al Carruth, for example.


If we accept what you say above about Jose Ramirez' 1As, then a logical conclusion would be that that model is after all not "scientifically" constructed. Consequently by default it was constructed, perhaps subconsciously, by instinct and intuition.



jshelton5040 -> RE: Myth's and Science (Jul. 15 2010 22:13:58)

quote:

ORIGINAL: Richard Jernigan



Jose III's excursions into mathematics and acoustics appeared to me to have little basis, and no strictly scientific support. He made no scientific measurements to support his theories, as does Al Carruth, for example.



Your point is very well taken. If Ramirez III had derived the formula for the perfect guitar how come the quality of his guitars varied so much?



Richard Jernigan -> RE: Myth's and Science (Jul. 15 2010 23:07:50)

quote:

how come the quality of his guitars varied so much?


According to both Contreras Sr and Manzanero, as well as Ramirez himself, Jose III insisted upon and enforced absolute adherence to his design. If this went so far as to insist on the same precise dimensions (and I don't know whether it did or not), then the 'oficiales' were prevented from compensating for the variability of the wood, as an experienced independent luthier would have.

Some believe that certain individual employees produced better instruments than others. In my experience of trying and buying a couple dozen 1a's, the quality of individual makers varied just about as much as the variation overall among all the makers.

All the same, I have been offered premium prices for my '67 cedar/cypress blanca just because it has Antonio Martinez' initials in it. It's not for sale. I've had it since it was new and I love it.

As to variable quality, Ramirez was fond of pointing out that certain instruments quickly rejected by respected professionals were praised and bought by other equally respected professionals. It felt and sounded like variable quality to me.

In his book, Ramirez wrote against the idea of voicing a guitar, or attempting to correct "wolf notes". He said that even if you did correct a "wolf note" it was likely to come back again later.

The independent luthiers I have talked to have mostly mentioned some philosophy and means of voicing instruments. Others have refused to discuss it. I often suspected they had a method, but regarded it as a trade secret.

RNJ



keith -> RE: Myth's and Science (Jul. 15 2010 23:10:15)

my take on ramirez's "science" is that he did a systematic trial and error and used his ears for the measuring device. given the technology available to him his ears were probably the best measuring device he could have used. as to variability of sound, i chalk that up to his understanding that wood has tremendous variabilty--and also an understanding that rent had to be paid and food had to be put on the table.



Richard Jernigan -> RE: Myth's and Science (Jul. 15 2010 23:18:36)

...but Ramirez was fond of pointing out that different people's ears arrived at different conclusions. There's nothing wrong with this, but it doesn't meet the definition of science.

By the mid-1960s Ramirez was well beyond putting food on the table. He was a prosperous businessman heading a large--on the scale of guitar making--enterprise. By the late 1970s he was wealthy, given the still-impoverished context of the Spanish economy.

Don't get me wrong. I enjoyed dealing with Ramirez, and came away with the greatest respect for him. He was a remarkable individual, combining artistry and taste with business ability in a way that perhaps only his great-uncle Manuel did.

Manuel Contreras Sr and Felix Manzanero both told stories of Jose III's dictatorial ways as boss. I made some comment to Contreras. He replied, "But he was a great man! Where would the guitar be without him? Where would we, Manzanero, Bernabe and I be without him?"

RNJ



Patrick -> RE: Myth's and Science (Jul. 15 2010 23:21:39)

Mr. Monttola also states flat sawn wood is stiffer versus quarter sawn. Isn’t stiffness desired in tops by builders? So if that’s the case, why are guitars not built with flat sawn wood? Like many aspects of life, has it been an issue of “well we have always done it that way”, or is it possibly aesthetics or some other reason?



Richard Jernigan -> RE: Myth's and Science (Jul. 15 2010 23:49:01)

Mottola surrounds the statement about flat sawn versus quarter sawn pieces with a cloud of caveats.

In December, 2006 when I ordered my Abel Garcia spruce/Brazilian, he showed me a few sets of Brazilian. I picked the straightest grain, most accurately quarter sawn one. I added, "You pick the top. You're the expert." He smiled and nodded. Then I asked which Brazilian set he would have picked. He indicated one of the slab sawn sets. I asked why.

"It's softer," he replied. The word I recollect is "blanda". Specifically, "less stiff" would have been "menos rigida". Garcia is a recognized expert on wood and its qualities, having published a book on the subject. We didn't pursue the subject further.

RNJ



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