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I was just curious now that Ervin's books have been out for a few months if anyone cared to render any opinions or comments on what they think, now that there's been a little more time to settle into it all.

I'm particularly interested in hearing from those that actually own or have read the books, and not so much in complaints about price, marketing, or who's drinking how much kool-aid. Any particular likes or dislikes? Was the content more or less than what you expected? I'm hoping people can feel free to be honestly critical without fear of lots of folks jumping to Ervin's defense.

I'd also like some more comments on the "Making of the..." book as most of the reviews I've read speak of the voicing-intensive one. I'm fairly well tooled and jigged-up already, but I'm still a relative newbie and it's always interesting to see other ideas and methods.

I also wanted to ask about the DVD... I honestly liked the production (particularly the audio) a lot better on the Gourmet Guitars video than I've seen on the online sample of the LMI DVD. I'm somewhat familiar with some of the more general concepts (cube rule, top vibration modes, etc..) so I'm leaning towards not picking this up anyway.

I am pretty close to picking up the books, just thought it'd be interesting to hear your thoughts. The price is not much more than I laid out for engineering textbooks that I used for 4 months, so I don't feel too bad about that. I've read enough of Ervin's articles and whatnot to know that I enjoy his writing style and I'll probably like the books.

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Jonathan Kendall, Siloam Springs AR

Check out the ANZLF forum on The Responsive Guitar, if you haven't already done so.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Yup, I've got that section of the forum bookmarked.

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Jonathan Kendall, Siloam Springs AR

I recently received The Responsive Guitar. I've read most of it and browsed the rest, so need more time to form a solid view. But I can give some preliminary thoughts, acknowledging they are just that.

First, as others have said, there is a great wealth of information and know-how in it, and much of it I've not seen anywhere else. It's very rare to find a luthier of his standing who is sharing so much acquired knowledge, so from a certain perspective, the book is priceless. The pedagogy of the book is to empower luthiers to be independent thinkers, not to 'train'--so there is very little guidance on how thick or thin a certain brace 'should' be, or if it should be there at all, for example. So it helps to read it with consistent expectations.

But, considering the cost, I'm also feeling a little disappointed in some of the content and editing (some of that is normal for a first edition). I'm finding that some of the mechanical concepts presented are hard to reconcile with mechanical engineering and some physical experiments. For me, this raises questions about the accuracy/reliability of information in other parts of the book. I.e., while the book as a whole is clearly valuable towards building great guitars, I'm confused about which info may be a 'useful way to think', and which info is also physically/mechanically true. 2 examples:

On p. 28, the steel string bridge is said to be superior to the lute bridge because the string angle over the saddle creates a downward force which more effectively drives a vibrating plate. But from Statics, a free-body diagram of a bridge+saddle (a pinless bridge is simplest to understand) shows that this downward force is canceled by the upward force at the string's ball-end anchor, so the net up/down force on the top plate is ~zero (assuming strings are ~parallel to the top). (Maybe the steel string bridge is superior because the downward force on the saddle creates a more defined end-point for the string, vs. the lute string's knot in front and travel through a small hole before getting to the rear anchor?)

p. 120 discusses the resonance of the air cavity / air mass (which the book refers to as the Helmholtz resonance, though according to Alan Carruth, "Helmholtz" applies only to a cavity with rigid walls, and a better term is 'main air' resonance. I'm assuming that the book is using 'Helmholtz' synonymously with the air cavity resonance of a real guitar, as many people do, especially since the rigid wall resonance is not very relevant to guitarmakers). The book says the resonance of this air mass cannot be changed by adding or removing wood, but, there are experiments from others and myself that have found different results. It does seem to be true that adding/shaving wood has _less_ effect on the main air resonance than the other resonances.

I don't mean to exaggerate potential weaknesses in the book. It's definitely very valuable: it has a lot of perspective and experience, it gives some very interesting history, it raises a lot of good questions on how to think about the guitar, it gives both empowering and some specific guidance, and it helps me start to notice many things I haven't seen or heard before. For me, so far, the weaknesses raise a whole new set of questions about which info I can rely on, but as that could be ultimately empowering, I'm guessing that Mr. Somogyi might be quite ok with that.

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David Malicky

You should post your points on the ANZLF "Responsive Guitar" Forum, which Ervin frequents from time to time to answer questions on the book.

My perspective on the downward force on the saddle is that in comparison to a lute bridge, which has no saddle, you only get the upward twist of the strings at the stop, which is an ineffecient transfer of string energy to the top. When you add a saddle, and have downward pressure on the saddle, the string energy is transferred to the top more efficiently. I get the cancellation of the forces you are talking about, but it becomes a rotational force on a pinless bridge, or any other bridge for that matter, does it not, which in turn puts an upward lift below the bridge and a downward push on the saddle, producing a dip in front of the bridge. It is, in my perception, this downward force which makes it better. I may be all wet, and I am not an engineer, but I can spell it!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I actually just put in my order for the books from LMI, so maybe in a couple months I'll come back and revive this thread so I can let myself know what I think about it. I'm pretty excited to dig into the books.

Thanks for your review and comments, David. I kind of gathered from the videos I've seen and some of Ervin's writings available online that he occasionally played a little loose with the engineering/physics terms (I'm an engineer). I can't really remember any specifics in that regard, just that I've felt that way while reading/watching. But for the most part I usually knew what he was getting at, so I don't think that'll bug me too much.

Obviously hard to say without reading the book, but I may side with Ervin on the bridge issue, or I might disagree with both of you depending on what Ervin said. I'm not that familiar with lute construction, so I can't really make any comparisons. That's probably for another thread, though. There actually have been a few pretty long threads talking about the forces acting on the saddle, bridge, etc...

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Jonathan Kendall, Siloam Springs AR

For a pinless bridge, a free body diagram enclosing the entire bridge would have a horizontal force exerted by the strings, a horizontal force representing shear at the bridge/top joint, and a distribution of vertical force on the bottom of the bridge. In the static case, the vertical distribution would have to sum to zero, and the tangential shear stress would have to balance the stress in the strings. This is modified slightly if there is some angle between the strings and the top. The action of the strings at a distance above the top also exerts a moment about the base of the bridge, and it is this torque that must be balanced by the distribution of the vertical force on the bottom of the bridge. Hence, as Waddy says, downward load at the front of the bridge, and pulling up at the back side.

I don't see, however, how a lute bridge would not be doing the same thing.

This picture is more complicated for a pin bridge, where tension in the string can be carried to the ball end in a vertical sense across any free body enclosing the bridge but not the top. Moments would still have to balance, though.

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Jim Kirby
kirby@udel.edu

I think the disadvantage of the lute bridge is the strings are just coming straight out of a hole in a tie block type bridge, with no break angle to assist in the transfer of energy.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I looked up some pics of lute bridges and I'd agree it's going to be loaded differently than a pinned steel string bridge. There's going to be a small downward load on the front of the lute bridge from the string's moment on the bridge (bridge will want to rotate towards the neck, same as a pinned bridge), but there's no additional force from trying to change the direction of the tensioned string like on a pinned bridge with saddle.

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Jonathan Kendall, Siloam Springs AR

Jim, Thanks for your lucid description. For those interested, I sketched a few FBDs, below. Both follow Jim's definition for the free-body: (a pinless bridge)+(a saddle)+(the bit of string from the ball end to just to the left of the saddle). This choice of free-body makes all the complex saddle and string loads internal; internal loads don't show up on a FBD. If the free-body were defined as only (a pinless bridge)+(a saddle), then the FBD and sum of forces and moments are more complex due to all the string loads, but the shear and normal stresses/loads on the top would be the same. The left one is like Jim's description with pressures (I assumed a linear distribution of normal pressure for drawing purposes). The right one replaces the pressures with forces for simpler math.

Jonathan, Glad the notes were helpful.

On lutes, here's a pic of the knot (cleverly used for tuning):
http://pellegrinlowend.com/tieit3.jpg
Waddy, yeah, the lack of a firm/defined contact point for the vibrating-string-end in lute bridges might inhibit vibration transfer to the top. And/or, the knot might dampen vibs via micro-slippage (how is the sustain on lutes?) The upper right pic shows the string does have a break-angle similar to a steel string, but the required diagonal force is applied to a flexible string that wraps around the bridge, as opposed to direct application to a rigid saddle. So, same force but very different paths. Some hypotheses.

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David Malicky

I could be incorrectly paraphrasing Ervin' book already, but he argues there (I think) that the difficulty with the lute is that the bridge is not exciting the sweet spot of the top, not necessarily with any deficiency of hte bridge itself. (There are old guitars with tied string bridges and no saddles as well, including some by Torres. The problems would mainly be with intonation, I would think.

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Jim Kirby
kirby@udel.edu

David - Thanks for the illustration. I need to learn how to do that efficiently some day.

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Jim Kirby
kirby@udel.edu

I think all that is great, and I may have been wrong about Ervin's perspective, but, the above drawings seem to ignore string pressure on the bridge saddle, and only deal with the pressure of the bridge on the top, which, IMO, isn't where the energy of the string is channeled.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Waddy- Trying to figure out what forces are at play is a non-trivial problem. What a free-body diagram (FBD) does is to help sort this out. For a guitar bridge, we could select many different diagrams depending on what we want to illuminate. In the case at hand, the issue is how the force (tension) in the string excites the top. The appropriate FBD cuts through the string and encloses the entire bridge (in cross-section) & exposes the forces at the bridge-top interface, as shown in David's FBD above. The downward force of the string on the saddle is internal to this diagram &, hence, does not appear. From this, I conclude that the "break-angle force" does not play a (direct) role in exciting the top. The break angle & the downward force on the bridge does keep the string seated on the saddle, which, of course, is important. A different free-body diagram cutting through the saddle & both ends of the string would show that force. I think David's FBD is the correct way to look at how the force in the string relates to forces in the top. I've played with a few FBDs to try & understand the forces involved, including the downward component associated with the string break angle, & came to the same conclusion as David. Hope this helps.

I see, then that would explain why, when you change the break angle, you change the sound of the guitar!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Hello John, Dave, Steve, Jim Kirby, Waddy, and all:

Thank you for your comments. Each of your comments deserves a separate response but I don't have that many hours to spare. Suffice it to say that I appreciate your perceptiveness and questions about how the bridge and saddle work -- as described in my books. To the extent that I've aspired to get people to think, argue, and debate, I think it's working.

I do have a few specific responses, though. For instance, one of you wrote:

"On p. 28, the steel string bridge is said to be superior to the lute bridge because the string angle over the saddle creates a downward force which more effectively drives a vibrating plate. But from Statics, a free-body diagram of a bridge+saddle (a pinless bridge is simplest to understand) shows that this downward force is canceled by the upward force at the string's ball-end anchor, so the net up/down force on the top plate is ~zero (assuming strings are ~parallel to the top). (Maybe the steel string bridge is superior because the downward force on the saddle creates a more defined end-point for the string, vs. the lute string's knot in front and travel through a small hole before getting to the rear anchor?)".

This may be correct, in theory. In fact, it probably is, as the writer seems well versed in the language of engineering. But I think that I'm saying something a bit different. I'm saying that the addition of the saddle to the earlier bridge design (the tie-block only version) adds a downward force that activates the top in a different way -- regardless of what technical language one brings to this dynamic. The fact is, you can audibly change the sound that comes out of a guitar by simply changing the angle at which the strings rest on the saddle and without changing anything else on the guitar at all: bracing, wood thickness, etc. The best way that I know of to do this is to string an average guitar up, play it for a while, and then come back and simply undercut the path of the strings between the saddle and the bridge pin holes. That way you remove minimal mass, don't change the torque, or the distance between the saddle and the strings' end points, or any other dynamic except the pressure that the strings rest on the saddle with. You'll hear the difference. Try it and you'll see. I might be that, technically, no extra downward force is created but that there's an increase in coupling between the strings and the saddle. This may be a semantic difference then; but the proof is in the pudding, and the sound will change.

You can then go back again and re-establish the former break angle of strings-over-saddle by jamming some hardwood wedges into the behind-the-saddle slots that you've just made. The guitar's sound will be as it was before. As I said, try it and you'll hear the changes.

There's a second comment that caught my eye:

"p. 120 discusses the resonance of the air cavity / air mass (which the book refers to as the Helmholtz resonance, though according to Alan Carruth, "Helmholtz" applies only to a cavity with rigid walls, and a better term is 'main air' resonance. I'm assuming that the book is using 'Helmholtz' synonymously with the air cavity resonance of a real guitar, as many people do, especially since the rigid wall resonance is not very relevant to guitarmakers). The book says the resonance of this air mass cannot be changed by adding or removing wood, but, there are experiments from others and myself that have found different results. It does seem to be true that adding/shaving wood has _less_ effect on the main air resonance than the other resonances."

I'm o.k. with the notion that "Helmholtz resonance" is properly applied only to a cavity with rigid walls instead of the air inside a guitar soundbox, and that the proper phrase for such an air mass -- and which phrase I ought to have used instead -- is the 'main air resonance'. But I am a bit hazy on the quibble with the books' statement that the main air resonance cannot be changed . . . or can only be changed a little bit. It seems self-evident that (if we are talking about the resonance of an air mass the size of a guitar soundbox) one would need to add or cut out A WHOLE LOT of bracing to change the air mass sufficiently to make enough difference so as to audibly change its resonant frequency. But, are we really arguing about such minutiae?

This may go to another comment on the thread, about my "playing loose with engineering jargon". From a strictly technical standpoint, I guess that I can accept that. I had a discussion similar to this one with another gentleman, on a different lutherie discussion forum: he 'strongly disagreed' with my formulation that the guitar is an air pump. I pointed out that I had not written a text for engineers, but rather a text that is directed to (mostly) non-technically-educated people. In writing my books I sought to illustrate my own learning curve, through use of ordinary and everyday language, in order to communicate intuitive concepts that bear on lutherie. I might rephrase this to read that I chose my words and phrases tactically, rather than academically correctly, toward such an educational end. Mainly, I want to get a point across more than I want to sound like a technical expert -- without, of course, giving misinformation. And this is quite appropriate, as I am not a technical expert. And certainly not in the way that Jim Kirby appears to be (please read his statement and compare the language with anything I've written).

Overall, in reading through this discussion thread I get the sense from your postings that, quibbles aside, you are all able to pretty much figure out what I'm saying to your own satisfaction, can use whatever part of this material you deem useful in the formulation of your own thinking, and ignoring what you can't use. This is as it should be.

Finally, I wanted to add another experience I'm having through the Australia/New Zealand Luthiers Forum. A month ago the administrators of that discussion forum were nice enough to invite me to preside/host a thread devoted to discussion of my books. They assumed that there'd be considerable interest in discussing this or that point presented in my writings. To all of our surprise, though, there has been rather little activity in that thread outside of people saying how glad they are to have me participate in such a thing. The flood of questions has not yet materialized.

I am sure that this is in part because rather few people in Australia and New Zealand have yet obtained my books, and also that others who have obtained them have not had time to read them fully yet. But there have been a few comments about how reading the books has produced 'ah-hah!' experiences that have answered questions these folks have been puzzled by over time, and that they consequently have no need to ask about these things. Yay!

What sense all this makes to me is that the books are being useful, one way or another, despite the informal language that they are written in, and managing to get the important information out to people's awareness. A lot of questions may come later. I expect that a lot of reinterpretations, reformulations, alternative perspectives and re-wordings will come as well. This is o.k.; learning will be happening. Like Frank Sinatra's song, we all like to do things 'my way'. Now, me, I just wanted to write my books 'my way'; but people's learning processes . . . well, they gotta do it their own way, no?

Cheers, Ervin Somogyi

Dear Ervin

Just a quick question from a newbie builder - although with a scientific background and a reasonable understanding of the basic principles. The subject is facinating, if at times bewildering even for someone who can understand the basic physics, but obviously made incredibly complex by the variations in the properties of the materials from one piece to another. My question is that given these complexities, which in your opinion (and I appreciate this is a naive question), has a greater baring on acheiving the consistency in tone that we all desire (albeit different tones for different models and different woods...) - Should builders look more closely at the physics or should new builders aim for consistency through the 'old -school' tap and listen? (I told you it was naive!) - The reason I ask this is that for many hobbyists, we all come to this from slightly different approaches, some are non players, with solid woodworking craft skills who simply want to build something different... and get hooked, others are players who 'always wanted to give it a try'... and get hooked, and in my case I have no delusions of doing this professionally, but aim to produce the best possible results and enjoy the learning process and for those who have other 'careers'; the 'destressing' that building provides - seriously

I have to admit, that given I work in a very scientific enviromnment, I prefer not to have to think about the 'calculations' and physics behind a build - but rather use the ear and learn that way - but it would be interesting to hear your take on whether (and perhaps at what stage in the learning process) it would become perhaps more important to think about these very complex issues scientifically (if at all)? I guess for many in those wonderfully naive early stages such as myself, the question always arrises, as from what we understand, many of these scientific processes would not have been used by many of the early masters - afterall an experienced hand will bend a piece of wood, and assess its stiffness - which is a manual deflection test afterall, albeit without a figure to record and log for future reference.

I ask this from the perspective that in a book (apologies as I cant remember the title) I saw analysis of either a Hauser or a Torres, (apologies but I cant remember) in which they provided info on the top thickness which varied by some 0.4mm in what appeared to be a random fashion - what it did not or could not explain was whether this was deliberate or just typical - given the likely tinkering with the soundboard after bracing... It naively suggest to me that this is a result of this 'tuning' by ear, hense the random nature of the thickness of the top in question... so gin in a naive way its easy to conclude that the 'ear' is not a bad tool to use...if its good enough for.... etc.

Having that scientific background and therefore appreciating the benefits that accurate data from a large sample can provide, simply makes it more confusing!

...but its also what makes this craft so facinating!

I'm feeling, smugly , vindicated! .................... Now I'm ashamed of my smugness! oops: Now I'm not!

Frank, I probably can't answer most of your questions, but I think many of the variations on the thickness of tops is a result of thicknessing with hand tools, planes and scrapers. Now that's only an opinion, but I also think that is responsible for the differences in size on a lot of the Torres guitars where the differences were only a millimeter or two. Those are hand building variants, not measured variables, I believe. I don't believe Torres was a precision builder, making guitar parts to the nearest .001".

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Hi, Frank, and everyone:

Thank you for your comments and questions. I'll start with this one:

Q: "Just a quick question from a newbie builder: given these complexities, which in your opinion (and I appreciate this is a naive question), has a greater baring on acheiving the consistency in tone that we all desire (albeit different tones for different models and different woods...) - Should builders look more closely at the physics or should new builders aim for consistency through the 'old -school' tap and listen?"

A: Hooooooo, boy! I'm afraid that I'm going to be making a lot of postings that are going to disappoint people and this one is likely to be one of them. Mainly, I can't tell you what the right approach is for you. People are right-brained or left-brained or some combination (and a few no-brained, but let's not get into that), and each mindset 'captures' and processes information differently. For myself, I'm very comfortable with the hands-on, ears-on, eyes-on approach. Others require a different set of cues. For example, there's a new book out that is very largely about the same things I've been writing about -- what makes the guitar tick -- but from a rigorously scientific direction. It's titled "Engineering the Guitar". Some people will read it and wonder why Somogyi can't write as clearly and lucidly as that. And vice-versa.

Both the scientific and the intuitive method work. And they can both equally fail. The one thing that I think everyone can pretty much agree on, however, is that the proponents of one approach find the others' approach incomprehensible. I think this ultimately has to do with brain organization and the comfort/discomfort that these architectures-of-the-brain bring to human problem-solving.

Here's an example that is at once ludicrously inappropriate yet perfectly apt: what kind of woman should you or I marry? Or, better yet: how should you or I behave on a first date (not with one another, but with someone we've asked out)? Hmmmmm, yes indeed; see the difficulties?

The best answer is for me to suggest that you find/decide what works best for you and follow that out. It is true that the historical lutherie pioneers didn't have electronic equipment, or even any great amount of mechanical equipment. They had hand tools, and their skills. And they made instruments that have yet to be surpassed. The fact is that, for most of us, nature has equipped us with senses (touch, sight, hearing, and assorted subliminal stuff) that are capable of INSANELY FINE DISCRIMINATIONS and control. Especially when we are young. These days, most of those abilities are not readily available to most of us, but are merely latent, because we have grown up without much reason to attend to the manual arts and their respective skill sets. We've been taught all kinds of other things.

Q: "I saw an analysis of either a Hauser or a Torres, (apologies but I cant remember) in which they provided info on the top thickness which varied by some 0.4mm in what appeared to be a random fashion - what it did not or could not explain was whether this was deliberate or just typical - given the likely tinkering with the soundboard after bracing... It naively suggest to me that this is a result of this 'tuning' by ear, hense the random nature of the thickness of the top in question... so gin in a naive way its easy to conclude that the 'ear' is not a bad tool to use...if its good enough for.... etc."

A: We'll never know. My guess, however, is that both those gentlemen worked their woods down skilfully with well-sharpened planes and scrapers. I don't know whether the measurements you cite are where the luthier stopped, or what someone may have left after a repair or re-finishing procedure. Let's assume the wood to be original, o.k.? Torres and Hauser would have worked their woods systematically, consistently, and to their own criteria -- again, with the use of hand tools only. And they would have both measured and tapped their soundboxes to 'locate' the optimal places to stop, as their prior experience had taught them to do.

It's been noted that the early makers were indeed consistent in their thickness measurements, etc. (at least, as much as working with hand tools can do), and if they made changes they did so slowly and over time. That is, they didn't hack wood off randomly from guitar to guitar, but would have tracked their work and made a change every now and then.

They would have been able to do this in part because they really were skilled woodworkers. They would also have been able to do this because it was common -- and still is common in Europe (although not in the United States) -- for a luthier to buy a whole tree; or for several luthiers to buy a tree and split it up. This is not only economical, but that way they could have a long-term supply of wood with CONSISTENT QUALITIES. And they would have been consistent: they will have come from the same part of the same tree, guitar after guitar. The norm in the U.S. is for a luthier to buy three or five tops from one of the suppliers, and in a few months buy a few more. And even if he bought a large number of tops at one time, the supplier's stash would invariably be a mix of slices and planks from many trees that were cut from various spots at different altitudes and under different growing conditions, and some of the slices would have come from the north side of the trunk and some from the south side, and some from near the center and some from near the bark . . . and there goes a big part of your work's consistency.

Tapping by ear is not inconsistent with either regular or irregular top thickness, by the way. The purpose of the tap is to reveal the voice of the wood at a certain stage of construction. And one can not only get a sense of the voice of the whole topwood, but one can get a sense of the differential responsivity of different quadrants of a braced top. If consistency is your goal, this is important because you might be wanting to elicit consistent quadrant-tones (you know: tapping on the treble side, the bass side, near the soundhole, near the tail block, near the center, farther out from the center, etc.) from a top that is not only irregularly shaped, but irregularly braced insofar as the braces almost certainly being different heights and varying distances from each other at specific places on that same top. You can 'compensate' for variations in bracing mass and stiffness by removing a bit of extra wood, or leaving some extra here and there.

Eventually, you'll figure out your proprietary preferred methods.

The best way to save time in a learning process that may take years, as far as I know, is to find someone who's spent a lot of time doing the work and is willing to teach or show you their own method and explain what they're doing.

Anyway, I'm not sure this does much to answer your question about what mindset you should most rely on in your lutherie efforts. I'd say: do whichever is most satisfying to you, without worrying about whether the other method might be 'more right'. They're both 'right'.

cheers, Ervin Somogyi

Many thanks for taking the time to respond, its much appreciated, and If I am honest its actually the answer I was hoping for! - This forum is a fantatsic environment and i have to admit I was surprised how many pros and seriously experienced amateurs WERE happy to share their methods thoughts and ideas, with us mere mortals. This is naturally very positive and helps improve the standards as a whole... but it can be confusing at times, as some there is naturally quite a deal of variation and opinion in approach which makes it more difficult to navigate through!

I dont think short cuts is really the right word, as I think most of us beginners appreciate the reality is that nothing replaces experience, but even during the early parts of the journey, on those first few builds, being equiped with just a few of the more expert approaches and ideas can naturally improve those early instruments - and that is why so many of us newbies are hungry to pick those experienced brains!

Thanks for you time!

Cheers

Frank

Thanks very much, Ervin, for your comments! Yes, you are definitely getting us to think (and argue, and debate)--and this is indeed good.

I like your thoughts on the scientific and intuitive mindsets--very insightful, and they explain a lot of the misunderstandings that can happen in these dialogues, as well as some confusion on my part. Closely related, I think, is that both these frames of reference use the same English language, with many overlapping words, but also many different meanings for those overlapping words. While these mindsets can seem quite different, I'm hopeful that a continuing dialogue can help each side understand and learn from the other. To that end, I very much appreciate that you take time to respond so thoughtfullly in these forums. Hopefully, ever-better guitars could be made from the best understandings of both sides.

I appreciate your clarification for the "downward force" and its relationship to activating the top (on page 28), particularly the role of increasing break angle on tone. Your ideas on the increase in coupling between string and saddle (which definitely involves a downward force in the engineer's mindset) due to larger break angles is a nice explanation to reconcile this particular debate.

I'm realizing my original post was not very clear on how adding/shaving wood can affect the main air resonance. I didn't mean to imply that it was through changing the internal volume (cubic inches) of the air cavity itself -- yes, that would require a *lot* of wood! I'm not an expert on this, but my understanding is that since shaving braces increases the flexibility of the top (or back), the vibrating air column at the soundhole "sees" a more flexible cavern of air, which results in a lower frequency for the main air resonance. For example, as the vibrating air column (the 'mass') moves into the soundhole, it pushes on and compresses the 'spring' of air in the box, but this 'air spring' also pushes on the flexible top (and back). The 'air spring' and the 'top spring' make 2 springs in series, and the total stiffness of the pair-in-series is lower than either one alone. So a more flexible top (or back) can have an effect similar to more cubic inches of air inside the box. The mass of the top (and back) introduce technical complexities and coupling effects, but those are over my head right now. The overall effect is there but not super-dramatic... e.g., as a learning experiment (like your book suggests), I did a lot of shaving on an overbuilt import OOO and lowered the 'main air' from 117 Hz to 106 Hz. A substantially difference, but it was no jumbo. More typically, my own Dreads have dropped 4-7 Hz from moderate shaving. Sorry for the ambiguous post before. I'm interested in what you think.

With more time with your book, I'd like to add a few of my 'ah-hah' moments. First, your explanations of the principle top modes are very clear and helped me understand some effects of brace placements and profiles. The multiple sections on how the X-brace interacts with the waist and bridge have been very helpful to a current design I'm working on (an SJ that will hopefully retain a Dread's punch). The many subtle differences between Spanish and steel-string guitars have been eye-opening. I was particularly amazed at the proliferation of Golden Means in the Spanish guitar, and lacking in a Dread. I'm also excited to try out lighter-built designs than my prior attempts and I'm sure I wouldn't be doing that had I not read your book. One question I'm wondering about: could you give more guidance on how to understand how lightly built is too lightly built for longevity, particularly for the top + X-brace? E.g., how does one predict if a bridge will over-rotate many years from now?

Thanks again for your thoughtful replies on this forum!

David

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David Malicky

So after a long couple weeks with many late nights at the office to finish up a project due yesterday, I was pleased to walk up on my porch yesterday afternoon and find my new Responsive Guitar books waiting for me.

A couple first impressions:
- Book quality is fantastic. I would almost rather have a cheap paperback to throw around the shop. My wife was encouraging me to just go ahead and let them get well worn instead of treating it like a museum piece. I used to work in a bicycle shop in high school in the early 90's, and we had a 2-volume set of old Schwinn Service manuals from the early 60's of similar hardback construction that covered hubs and other bike parts from the 40's on up. I bought a set on ebay a few years ago and actually enjoy seeing the grease prints on the pages. Hopefully my TRG books will have worn corners, glue spots and rosewood fingerprints staining the pages a decade from now.

- I haven't read many comments on the Making Of TRG volume. As a novice I was interested in this volume but suspected it might be a little redundant given the wealth of instruction available in online forums and in other books/videos. I've only skimmed it, but did just read through the chapter on gluing the bindings which has been a problem area for me. I really appreciated the level of detail, as often it's the tiniest, most subtle things that can sabotage a seemingly simple step. A lot of your construction techniques are outside of the internet general consensus of how to do things (or IGCOHTDT as I like to call it), so it seems like it will be refreshing and valuable info.

Anyway, I'm definitely not one to be a cheerleader or only offer only positive comments, but I'm really impressed so far. No buyer's remorse here.

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Jonathan Kendall, Siloam Springs AR