Hello William, I have this doubt I cannot wait for another month. Suppose we have two identical tops, same thickness, same rigidity. Let's say they are clone of each other. One you build flat or with a slight arch on the lower face brace (as described in your book), the other one is built on a concave dish (I started to use one). Do you think you need the same bracing? Or, in other words, if you use the same bracing on the two tops, do you think you will get the same results? I am asking because I started to use a concave dish. I like the result better, but I suspect that the top is much stiffer this way and using the same bracing as built flat, will inhibit vibrations. I am not sure, but this is an aspect where I notice a difference. It might be one of those macroscopic aspects you were telling me.
Grazie, Enrico
====================================
It is very hard to answer your question in a helpful way. You're presupposing that there is a "good" stiffness opposed to a "bad" stiffness. But how do you ascertain or quantify those two? How do you predict or evaluate the results of the two? How can you be certain that the difference in sound is the result of that particular difference in construction? Do you know precisely how much stiffer the top becomes when you impart a "slight" dome to it? How would you measure that? How would you evaluate the results in a way that can facilitate a clear choice? In practical terms, the question is moot, unanswerable. There is no "tipping point", but shades of gray. You have to be very careful of assuming you may ultimately be able to master the "science" of something which is essentially a cultural artifact, that ultimately is to be evaluated subjectively.
The universal consensus is that the lower transversal needs to be slightly arched. It is a matter of opinion, however about the value of imparting a "dome" to the area below. I don't do that, so I cannot advocate or dismiss that technique. I'm not even sure how gluing the fans against a hollow form actually succeeds in doming the soundboard. Does it? Does it dome it more than just the residual dome resulting from the curved transversal? Does glueing together two elastic components while both are pushed against a curved surface impart a permanent curve into the results? How permanent? You would imagine it does. But...does it? Then, what results when the entire elastic assembly is subjected to 43 kilograms of string tension? What happens to your minuscule dome then?
Assuming it actually succeeds in doming the soundboard, you would imagine that the bridge would then have to be hollowed to conform to the curve--closely. Then you would also have to curve the bridge block used temporarily underneath the top to clamp the bridge to it while it's glued, in order not to disturb that careful dome. That means the bridge is now sitting higher than it would be on a flatter top. the fretboard inclination would have to account for that.
I'm too lazy to do all this, especially since the advantage of the extra work is inconclusive, or unprovable, and when too many world class guitars just aren't made that way. My philosophy is, also, that the simplest solution is more often the best solution.
But if you believe that the domed workboard gave you better results---go with it!!! Perhaps the dome thus imparted is interacting synergistically with some other aspect of your sequence and design that you may not be (and perhaps will never be) aware of. All you have, really is your belief. Or, you can fritter away your concentration imagining impossible scientific experiments that perhaps may illuminate the quandary. But I think that is an illusion. Those thought experiments (two perfectly cloned tops, one made one way, the other made the other way...which would be "better?") I can't image to be ultimately very productive.
Go with your belief. That is what is called intuition: following the path which you cannot prove will be successful before hand. And my experience is that your intuition gets better the more you exercise it. If you domed your last top and didn't "compensate" with the stiffness of the bracing--and the results were clearly positive--assume it was because of what you did differently, or at least know that you did no harm, so keep doing it and be content and turn to something else on the agenda. It is the habit of modern man to want to KNOW before proceeding. But you often cannot Know. And must proceed.
All I know is that my guitars became consistently successful--by the responses I get from clients--after making many of them--and relying on my intuition. Your initial success evidenced by the acceptance of your last guitar by a discerning musician, is the product of your trusting your instincts and then following them with persistence.
Friday, July 3, 2009
Sunday, June 28, 2009
An imagined problem
I recently bought Guitarmaking Tradition and Technology, as I will be building my first classical guitar once I've tooled up for the job. The book is great...love it to bits! Thank you so much. :~)
Perhaps you would clarify something to do with the build process that is nagging at me a bit? It is to do with joining the back and top to the sides. In your book you show the sides/lining being sanded with a large flat board, giving a flat surface. Yet the top and back are radiused, meaning they will contact the sides at an angle. The thing that is nagging at me is that this would give a rather small joining surface between the sides and the back/top. Perhaps the effect of the radius over the distance of the side thickness and lining that serves as the gluing surface is so small that it doesn't matter? Am I on the right track?
I hope you will indulge an old fool with his silly questions.
====================
Smart people are the ones that ask the questions. Silly old fools think they know it all already.
I understand why you find a problem that ought to exist, in your mind's eye. But in practical real-world terms, it simply does not exist as a problem. Guitars have been made for eons without the elaborate CAD/CAM domed sanding shells that the suppliers would just love to sell you to satisfy those imagined "common sense" problems. If every thing on the guitar was rigid as glass there might be a problem. But wood is elastic and the offset from flat of a 1/4-inch segment of a 15 or 16-inch chord of a very, very large circle is next to negligible and what there is flexes under pressure to come together and adhere permanently. So my advice is to worry about other things, and put that to rest.
Perhaps you would clarify something to do with the build process that is nagging at me a bit? It is to do with joining the back and top to the sides. In your book you show the sides/lining being sanded with a large flat board, giving a flat surface. Yet the top and back are radiused, meaning they will contact the sides at an angle. The thing that is nagging at me is that this would give a rather small joining surface between the sides and the back/top. Perhaps the effect of the radius over the distance of the side thickness and lining that serves as the gluing surface is so small that it doesn't matter? Am I on the right track?
I hope you will indulge an old fool with his silly questions.
====================
Smart people are the ones that ask the questions. Silly old fools think they know it all already.
I understand why you find a problem that ought to exist, in your mind's eye. But in practical real-world terms, it simply does not exist as a problem. Guitars have been made for eons without the elaborate CAD/CAM domed sanding shells that the suppliers would just love to sell you to satisfy those imagined "common sense" problems. If every thing on the guitar was rigid as glass there might be a problem. But wood is elastic and the offset from flat of a 1/4-inch segment of a 15 or 16-inch chord of a very, very large circle is next to negligible and what there is flexes under pressure to come together and adhere permanently. So my advice is to worry about other things, and put that to rest.
Tuesday, March 3, 2009
Twelve-string setup
I have a question for you about 12 strings guitar set up.
I do not have much experience in playing and setting up 12 strings guitars.
I am setting up a 12 strings guitar and I have found that is difficult to
press two strings, on the same row, that have different diameter with the
same pressure. So I find that if I press the fifth row of strings (0,039 - 0,018) I am able
to press the 0,039 string well but the 0,018 not so well and it rattles
because it is not pressed well. This happens also for the third, fourth an sixth rows (less in the sixth). This guitar has good action (1/16 & 3/32 at 12 fret).
1. Is it possible to reduce this difficulty installing higher frets (this
guitar has 0,04" tall frets).
2. Is it possible to reduce it setting each string row more apart?
(each row is more or less 1/16 apart at the nut and 3/32 apart at the
saddle). Which distance do you recommend?
3. Do you think that it is better to cut nut slots with different height in
the same row to gain more comfortable action at the first fret?
That's all.
I Hope you will find the time to answer me.
========================================================
The greatest clarity of sound on a 12-string is the not the result of fret height, or in a difference of slot-depth at the nut for each member of the string-pairs. In your case I see the following difficulties:
1- There is no getting around that a 12 string player has to develop more grip strength than a 6-string player. A beginning 12-string player will have clarity problems no matter what the string spacing or string set up is, until the player realizes that more muscle pressure is necessary to press both strings down firmly for a clear sound. It takes specific hand skills to play a 12-string expertly. So be assured that a weaker player will undoubtedly complain about clarity no matter how expertly made or set up the 12 string is. So as a builder or repair man, you must be ready for that dilemma and not blame yourself exclusively.
2- Your strings are indeed too closely spaced at the nut, if they are 1/16 inch (1.6 mm). That can also contribute to a lack of clarity if the strings clash together, the smaller string being overpowered by the larger. At the nut, the optimum spacing is an average of 3/32, with the trebles a tiny bit less and the basses a tiny bit more. At the bridge, the diameter of the bridge pins is a limiting factor, since it is not good practice to cut grooves into the saddle. However if your pins are very fat, you may make a clearance notch in the bridge pins to insure that the optimum spacing between the pairs is 1/8 inch.
3- Your action height is too low. The thinner string will be the first to be dampened when it strikes the frets. So what is the optimum height? Optimum is the highest action possible, given the limits of the players strength, that is, not so low that the strings jangle and rattle on the frets, yet not so high that the player can't press them all the way down. That's the dilemma: a beginning player will complain of difficult action even at a very low setting, which then makes the strings easily contact the frets; then complain about the lack of clarity. Expert 12-string players have a well-developed grip, but also have developed an instinctive ability to press the strings appropriately and efficiently no matter what the string height. But given the choice, they prefer a high action to a low because they are strong enough to overcome it, and it gives them a better tone and a wider dynamic range.
So the 12 string is not an appropriate instrument for a weak or beginning 6-string guitarist. So don't let them blame you for their own lack of development. You learn to play the 12 string guitar AFTER you have become a competent 6-string player. If a weak beginner insists on playing with a very low action, they must accept a sizzly, jangly, unclear sound until they become strong enough to play with a raised action.
I do not have much experience in playing and setting up 12 strings guitars.
I am setting up a 12 strings guitar and I have found that is difficult to
press two strings, on the same row, that have different diameter with the
same pressure. So I find that if I press the fifth row of strings (0,039 - 0,018) I am able
to press the 0,039 string well but the 0,018 not so well and it rattles
because it is not pressed well. This happens also for the third, fourth an sixth rows (less in the sixth). This guitar has good action (1/16 & 3/32 at 12 fret).
1. Is it possible to reduce this difficulty installing higher frets (this
guitar has 0,04" tall frets).
2. Is it possible to reduce it setting each string row more apart?
(each row is more or less 1/16 apart at the nut and 3/32 apart at the
saddle). Which distance do you recommend?
3. Do you think that it is better to cut nut slots with different height in
the same row to gain more comfortable action at the first fret?
That's all.
I Hope you will find the time to answer me.
========================================================
The greatest clarity of sound on a 12-string is the not the result of fret height, or in a difference of slot-depth at the nut for each member of the string-pairs. In your case I see the following difficulties:
1- There is no getting around that a 12 string player has to develop more grip strength than a 6-string player. A beginning 12-string player will have clarity problems no matter what the string spacing or string set up is, until the player realizes that more muscle pressure is necessary to press both strings down firmly for a clear sound. It takes specific hand skills to play a 12-string expertly. So be assured that a weaker player will undoubtedly complain about clarity no matter how expertly made or set up the 12 string is. So as a builder or repair man, you must be ready for that dilemma and not blame yourself exclusively.
2- Your strings are indeed too closely spaced at the nut, if they are 1/16 inch (1.6 mm). That can also contribute to a lack of clarity if the strings clash together, the smaller string being overpowered by the larger. At the nut, the optimum spacing is an average of 3/32, with the trebles a tiny bit less and the basses a tiny bit more. At the bridge, the diameter of the bridge pins is a limiting factor, since it is not good practice to cut grooves into the saddle. However if your pins are very fat, you may make a clearance notch in the bridge pins to insure that the optimum spacing between the pairs is 1/8 inch.
3- Your action height is too low. The thinner string will be the first to be dampened when it strikes the frets. So what is the optimum height? Optimum is the highest action possible, given the limits of the players strength, that is, not so low that the strings jangle and rattle on the frets, yet not so high that the player can't press them all the way down. That's the dilemma: a beginning player will complain of difficult action even at a very low setting, which then makes the strings easily contact the frets; then complain about the lack of clarity. Expert 12-string players have a well-developed grip, but also have developed an instinctive ability to press the strings appropriately and efficiently no matter what the string height. But given the choice, they prefer a high action to a low because they are strong enough to overcome it, and it gives them a better tone and a wider dynamic range.
So the 12 string is not an appropriate instrument for a weak or beginning 6-string guitarist. So don't let them blame you for their own lack of development. You learn to play the 12 string guitar AFTER you have become a competent 6-string player. If a weak beginner insists on playing with a very low action, they must accept a sizzly, jangly, unclear sound until they become strong enough to play with a raised action.
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