Official Luthiers Forum!

[QUOTE=Brock Poling]
I think the objective of tap tuning is not necessarily the single goal of making a "great guitar" it is the process of getting predictable and repeatable results.

Clearly this is the great mystery of what we do. I am increasingly convinced that regardless of what camp you are in: science -- where you measure everything and use data to try to predict results, or "art" where you tap, listen, tap, listen etc. I think at the end of the day the really really really significant variable that determines proficency is ** experience **. Both approaches seem to yeild decent results but you need to have a (reasonably) sizable base of experience with your approach.

Again, not to say that your early guitars can't be very good, but I suspect that without a decent base of experience controlling or predicting the outcome will be very difficult.



[/QUOTE]


I think you are right Brock

As with the original article that Hesh posted to start the thread, I don't doubt for one minute that BC's method works perfectly for him he has honed it over many years, and knows exactly what he is looking for because of his experience.

Just as people whot Tap Tune or use Glitter Patterns have worked out their technique and it works for them.

The difficulty comes I guess when trying to hand that method to some one else, but then I think thats whats great about guitar making, you take all of these methods and techniques you learn from various places and blend bits of them with some of your own methods to create your own style.

[QUOTE=burbank] Where's Mario? [/QUOTE]

Canada RussellR38819.749849537

It could be that Cumpiano is right and everyone that taps is wrong, or Cumpiano just doesn't get it so he discounts it for his lack of understanding. There isn't much middle ground as I see it. I've completed 2 guitars and I have 2 more pretty close, so I am not trying to speak as an expert, but I'm trying to logically break down the comments to their logical conclusions.

When I read his statements about a year ago I thought he was right and what he said makes sense. After learning how many luthiers tap tune, I'm not inclined to say that they are fooling themselves. I own his book and I have a lot of respect for him, but no one is right about everything.

_________________
"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

I don't think there's any one way to do anything in building something as abstract as a guitar, especially when related to how it will sound. BC is a great treasure trove of information but just because something works for him does not mean it will work for other builders, I do agree that proper wood selection is the key fundamental. Let's face it, if the wood is floppy your going to be hard pressed to get anytype of consistent tone out of it.

I also think he's correct and it's something that Mario stated a long time ago that stuck with me, 'it takes time and lot's of building to know what your "sound is
'. But it's *my* personal belief that once the guitar is assembled and you've been consistent in your bracing that you can greatly effect the sound by 'bonking' it and using your senses to thin the top until you get the tone your looking for. Nothing scientific, it's all intuition and for me it seems to work (at least so far).

I honestly have learned more from the community of builders than I have any one individual, but that being said I would say that BC had a huge effect on how I build, if you look at his current work, he now uses a mold and heating blanket and has a new modified bracing pattern (with single fingers off the X), I'm tinkering with that on my next couple to see what that sounds like

Good topic...

-Paul-

_________________
-Paul-

Patriot Guitars

I'm reminded of the story of the fellow that was talking with an educated Irish woman, who kept mentioning the 'little people'. He asked her if she believed in them and she said: "No, but they're out there anyway."

Let's clear up one thing: there are at least two different kinds of 'tap tunung', which you could distinguish by the names 'free tap tuning', that is, with the top off the guitar, and 'assembled tap tuning', with the top on. If you're one of those folks who put the top on the rim first, you could also have 'open' and 'closed' assembled tap tuning. These are much different things.

Most things have a lot of different possible ways in which they can vibrate 'freely'. That is, with enough input power you can make anything vibrate some at any pitch you want, but here we're looking at what the thing 'wants' to do, based on it's own mass and stiffness distribution. When you tap on something, you're activating every possible way it can vibrate that is moving at the point where you tap it, and stationary at the place where your'e holding it. In addition, you're going to hear mostly those 'modes' of vibration that are moving at the place where your ear is.

From this you can see that there's room for a lot of confusion when you talk about 'tap tones'. How you hold, and where you tap and listen, can make a huge difference in what you hear. On top of that, there's the whole business of how you describe it when you talk to sombody; everybody uses those descriptive terms differently.

This is why I've always had trouble understanding all the different systems of tap tuning, and I suspect BC has the same issues. I will say that I understood Dana Bourgeois' system a lot better after he was able to demonstrate it to me at a GAL convention. I'd venture a guess that most of the poeple who use them either figured it out for themselves or else got a fair amount of hands on instruction. There's nothing wrong with that, except it's hard to spread the word very widely that way.

Assembled tap tuning is the easier system to justify on theoretical grounds; after all, you're looking at what the guitar is doing when it's all together. Even without theory you can, over time, learn what good guitars 'should' sound like when tapped. After all, it's those resonant frequencies and patterns of the aseembled box that give it it's timbre. With even a little understanding of what those modes look like you can often pick out the most important ones fairly quickly. I taught a kid to identify the 'main air' resonance of guitars via e-mail, and he used the technique to win a science fair by tabulating the air tones of all the guitars at one store in NYC. THere's a problem, though: I once built a 'match pair' of guitar that had the exact same assembled tap tones, and they still sounded a little different. I _think_ I know why, but....

Similarly, if you understand what a 'free' top is likely to do you can often pick out those modes by tapping. However, 'free' plate tuning is on much shakier theoretical grounds; after all, everything changes when you glue the top on the guitar, right?

Well, yes and no. I'm not saying we've made huge theoretical leaps of late, but I am pretty confident, based on a number of experiments, that the _shapes_ of some of the 'free' plate modes can be useful predictors of some aspects of tone quality in the assembled guitar. That's what was different on my 'matched pair. Sadly, of course, the shapes of the modes are not something you can hear very well.

There are three things to keep in mind, though:
1) Since the 'standard' guitar designs have been sweated over for so long they've gotten to be pretty nearly optimised. That means that if you build to 'standard' dimensions you'll likely have a pretty good instrument. It also means that the objective spread beween the 'best' and the 'average' is pretty small, and it can be worthwhile to put in the effort to get that last little bit.
2) The human mind is really good at drawing conclusions and extracting patterns from incomplete and fuzzy information. We're so good at it that we often see patterns that aren't there! That's where science comes in: it's a way of weeding out the 'fake' patterns.
3) To paraphrase Feynman; to be a good scientist you need to try very hard not to fool people, and the way to do that is first not to fool yourself. The problem there is that you are the easiest person for you to fool. It's entirely plausible that all of the folks who are 'tap tuning' are fooling themselves: they've gotten good at doing whatever it is that makes their guitars come out right, and they believe it's because of the tap tuning. Fine. OTOH, maybe the people who _don't_ tap tune are fooling themselves. After all, it's just about impossible to _not_ tap on, or otherwise cause a top to sound while you're working on it, and it would be perfectly natural to assimilate those signals subconsciously and do things that 'look right' based on them. I recently found, for example, that the sound of scraping or sanding can contain information about the modes that are active at that spot.

So, maybe I don't _believe_ in tap tones, but....   

The best part from a newbie point of view is, i think, being opened minded to all camps (feelers and scientists), i always thought that the guiarmaker-masters had to have long years of woodworking experience in different fields and that lutherie was some sort of an accomplishment or higher challenge they'd take because of all the tools a luthier needs to build an instrument!

I'm saying this because many of you, by pure kindness and generosity, will encourage a newbie from time to time in his new addiction by saying that he doesn't need so many tools to be able to build a guitar and to which i agree but, if you look at what it takes in terms of thinking, virtue, tooling, skills and material to build an awesome and truly great guitars, you can see that both camps come in handy together.

Sorry, my pocket change is all gone, will paypal the $0.02 later ok?

I don't know "sickum from come here" on this subject but have enjoyed the thread. I have the Cumpiano book as well and have done a fair amount of tapping and thumping, at this juncture, why, I am really not sure. I tip my hat to the folks who can make determinations on the final outcome off the plates, maybe in time I will better understand as well. They all sound good to me. Serge I do feel up my wood pretty regular so I might be a "feeler". I follow the same process, buy top quality woods, focus on the thicknessing, bracing and construction, (and the great tips from the OLF) put it all together and let the big dog eat.

Mike

We are not alone Mike! No We're not alone who feel like that!

UP a few SProcket mentions if your wood is floppy dont expeect any kind of consistant tone out of it. IMO opinion wood is what you make with it. I have made a fair number of guitars now, dont really tap tune at all, and have used sitka, engleman, adirondack, euro, bearclaw, redwood, curly redwood, cedar, koa and walnut as topwoods. I dont thickness any of them to a given number - its all by feel and flex, that works with my bracing pattern and sizes. Two of the most complex sounding guitars I have built have thick tops by anyones standards - my Dragonfly has a floppy sitka bearclaw top, used because the figure was intense, that ended up about .135 (compared to most sitka that I use at about 110 to 115). Another guitar, with red cedar on top, was about .145. I tend to build by strength of materials, not tones. My thoughts have always been that the wood will only give you what it can, nothing else.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

[QUOTE=Hesh1956]Then along came Bob Taylor who... produced some pallet guitars. Has any one ever heard/played these things? Were they any good?
[/QUOTE]
Yes, I heard the original, very briefly, at the 1995 ASIA Symposium. It wasn't available for general playing, but someone (can't remember who) picked it up in the theatre lobby and did some pickin'. It sounded pretty good, but certainly not great. Remember, this guitar was built with the same attention to detail and quality control as the best Taylors, so I don't think that just anyone could build a good guitar from pallets.

I think we all tap on them.   Whether our subsequent adjusting is as a response to the tapping, well that's another issue.

I tap on them, and I do listen for something...and that something is mainly clarity and sustain.   I can now tell when I've got a guitar box glued up whether it's going to kick ass or not, and if it isn't quite right, I may just go in and carve a bit here or there to bring up one thing or another that I'm after.   

But I don't mess around with crappy wood; I use the best I can buy and then I reject some, and the floppier stuff that'd decent goes on smaller guitar bodies or it is graduated thicker.   I simply won't use heavy, floppy top wood, though I've seen some that looked absolutely beautiful. Those can go on my Renaissance semi-hollow guitars.

     It would probably be best if it were possible for you to play one of Bill's guitars and then offer an objective comparison to those build by others who employ tap tuning in their instrument building, but good luck actually finding a guitar built by Cumpiano.

    All of the items lists as important by Bill are essential to the construction of a great guitar, but the assumption that they are in any way more important or can in any way take the place of tap tuning can be easily debated. Tap tuning simply allows the luthier to take those four steps after they've been applied by the builder and work from there to further coax tone from the woods invloved to bring them as close as possible to their tonal potential.

    I use a quirky and possibly cryptic techinique in my building that hs proven its value over the years that I've been building guitars. I painstakingly listen to every piece of bracing stock and top plate that comes into my shop and then separate them onto groups according their fundamental resonant frequency. Stacks of tops and boxes of bracing material are lined up accordinto whether they have a low, medium or high resonant frequency. I always consider these tones when selecting bracing to go on every top or back. It can dramatically affect the overal resonance and response of any plate as the components that make it up are matched to work best together.

    For example, a top that is very stiff and light and exhibits a high resonant frequency or "tap tone" won't be complimented or mamimized by bracing that exhibits that same high tone. Bracing with a warmer or lower general frequency will help to balance it so I select them accordingly. The desires of the customer as far as tone is concerned also have a bearing on the selection of the components so all is considered when making those choices.

Only after reading extensively on the work and methods of many of the great violin builders of old and their deep consideration of stiffness and weight of individual components as well as its distribution through the careful graduations carved into the plates did I begin to notice these things and employ some of the ideas. The graduations on the tops and backs of all of the greatest violins are never symetrical, but are cut with careful consideration for the weight distribution throughout them. We work with bracing separate from the top, so we have to apply different considerations, but many of the same effects are present as we really pay attention to and document the subtle effects of very small changes. It's interesting and fascinating and is something that many have tried to apply formulas and equations to to no avail....except for the simplest of all equations...one skilled builder + the right materials matched to one another = a fine instrument that approaches its tonal potential.

    I've watched as workers in any of several of the largest factories will just blindly grab the bracing that is on the top of the pile in the box next to their bench, apply glue to it and stick it to the top that was next on the stack. No tone consideration...no flexing...no tapping....just get it together as quickly and neatly as possible. This is where the power of deeply established designs and dimensions is shown most proudly. Generally good and consistent tone can be achieved by applying those four principles that Cumpiano has listed as of paramount importance, but the solo luthier can work with that as only a beginning point and tap tune as he coaxes the most from the combination of woods in the guitar. They are great applications, but should be only the beginning for a skilled builder.

   That is one of the chief beauties of a small shop or solo luthier being commissioned by a discerning and educated player to build a guitar. The time can be taken to discuss the desired tone and response characteristics and to carefully select each component that will be married together to create the tone generating relationship that is a guitar. Plates, braces and all other components being selected according to their respective tonal contributions and the effects they can and will have on one another is of paramount importance in the construction of any instrument.

    The right bracing can push a top that is good to be a top that is outstanding and the tap tuning process, when performed correctly, can take it even farther.

   I've read Bill's book and have given much of it deep consideration over the years, but am not a strong proponent of it as a great source for reference or instruction for the luthier in the real world. Sorry.

   Let us know when you find one of Bill Cumpiano's fine guitars to play and are able to give that comparative review. It will make for an interesting thread here.

Regards,
Kevin Gallagher/Omega Guitars

[QUOTE=Kevin Gallagher]    I've watched as workers in any of several of the largest factories will just blindly grab the bracing that is on the top of the pile in the box next to their bench, apply glue to it and stick it to the top that was next on the stack. No tone consideration...no flexing...no tapping....just get it together as quickly and neatly as possible.[/QUOTE]
Yep. Probably why there's so much difference among guitars from the same factory. Every once in a while, something astoundingly superior comes along, and it's probably just an accident. Several years ago, I had the luxury of time in a store with a large acoustic selection (Elderly Instruments in Lansing, MI) to find a solid-wood guitar that I could afford (nothing over $2K). I ended up with a Martin OOO-16--at the time, the cheapest non-dred Martin available. After, literally, hours of back-and-forth comparison, that guitar sounded the best of any I tried costing up to $1K more! I bet, though, that several people on this forum have built first guitars that are better than that OOO was.

I agree partially with your statement Tony, a guitar is not a top or a back or any singular entity, it's a reflection of all it's parts. I only measure my tops at the very outset to give myself a working parameter to start from, after that I simply stop measuring and start listening as I work them down. I also flex and feel along the way, I actually start with them a little thick and work form there.

But I think Kevin hit upon a key point, your guitar will only sound as good as it's weakest part, those of us who build by hand have the time and passion to sweat over little details that a large shop would simply try to normalize. Kevin's finicky nature with his bracing can only lead to a much better sounding instrument in my experience, you certainly can make a nice sounding guitar out of a mediocre top, but why??

There's no 'magic' formula for getting good sound, so my point was more that if you start with a dead top (and I've had a few, trust me :) then your at the very least facing an uphill battle to make it sound it's best. So if you can start with a top and bracing that at least has some resonance (which you can hear from tapping) then you increase your odds of getting a better sounding guitar.

Cheers

-Paul-

[QUOTE=TonyKarol]   UP a few SProcket mentions if your wood is floppy dont expeect any kind of consistant tone out of it. IMO opinion wood is what you make with it. I have made a fair number of guitars now, dont really tap tune at all, and have used sitka, engleman, adirondack, euro, bearclaw, redwood, curly redwood, cedar, koa and walnut as topwoods. I dont thickness any of them to a given number - its all by feel and flex, that works with my bracing pattern and sizes. Two of the most complex sounding guitars I have built have thick tops by anyones standards - my Dragonfly has a floppy sitka bearclaw top, used because the figure was intense, that ended up about .135 (compared to most sitka that I use at about 110 to 115). Another guitar, with red cedar on top, was about .145. I tend to build by strength of materials, not tones. My thoughts have always been that the wood will only give you what it can, nothing else. [/QUOTE]

_________________
-Paul-

Patriot Guitars

Kevin and Alan, as always, your input is so appreciated, i love the idea of balance in everything, sometimes and more often so, we have to rely on intuition because some parameters are just unpredictable.
i also like the more scientific approach were the apprentice will make an effort to take some measurements here and there in order to repeat successes but always in harmony with intuition.

The guitar i've built was made more with intuition than science, it was OK for me to proceed that way because my goal was not so much for my first to be beautiful and awesome like the ones showed here every day, i was aiming for a loud soundbox which i obtained by visiting websites (which offer plenty of pics and quick descriptions but not a detailed journal including all the tricks of the trade nor the mishaps that everyone knows here) and resourcefulness to get to my goal, So yeah, intuition and some miracle made that guitar sound heavenly to my ears!

Lucky?, don't know, guided? sure was!

Kinkead's idea is to reduce the braces until the tap tone just starts to drop. To me that means the bracing is as light as it can be, and any further carving will make a floppy topped boom box.

I love the art of feeling and listening to the wood until YOU decide it is right.

Kurt

Ya know,

One of the most interesting parts of the luthiery world is the ability of many great builders to share there information. Another very interesting part of this community is the hunt for the "Holy Grail". I quote from the introduction to David Hurd's book "left Brain Lutherie:

"To me, these voicing descriptions are more or less expositions of an experience by the writer rather than a guide to building. One is left with "Well, you just have to do it until you get it," analogous to "cook until done." I respect the final product that many such builders produce, but I am personally frustrated by my lack of ability to apply their approach"

I live in Dave's camp on this one. When BC and I discussed this very topic we agreed that every great builder has the same goal at the end, and they probaly travel the same road to get there, it is just their perception, or the ability to describe it that is different. By tapping or by measuring the stiffness or by following other wood structure parametres, you are really doing the same thing, maximizing the responce of the top. The problem for us new builders is that we want to know how to do that NOW! And then as Al states, science is based on removing the bias. By repeating the procedure rather than the just going by feel, you can get better predictability. I, for one never discount a method, I may elect not to use it but I always find it interesting to see how others do things and then, as Russel noted, modify to what works with your tools, space, ability and philosphy. That really is the best you can do.

Another great thread!! Thanks for getting it going Hesh.

Shane

_________________
Canada

What Shane said and i should have thanked more people on this great thread, I appreciate all views here!

I really like what David Hurd has to say about those that measure soundboard properties and those who use other methods to determine the soundboard characteristics. In the end, maybe the question is how can I either build a better instrument or how I can repetitivly build great instruments. I think his thoughts would also cover differing methods of tuning the top.
"It's a reasonable question to ask "Why measure wood properties when so many builders don't and still make good instruments?" For me the answer is two-fold: first, I feel that these builders actually do make such measurements, but choose to do so using their own senses rather than measuring devices such as micrometers and balances and such. They've developed their own internal databases to refer to and function well within that environment. No one makes a great instrument time and again without some sort of reference knowledge. Second, some of us are more comfortable putting actual numbers down so that we can refer to them later when we see how an instrument turns out well. Such numbers are also useful when we want to compare our measurements with work done by others."

I really like the fact that a left-brainer is able to accept the fact that many road may lead to the same destination.

Philip

_________________
aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.

Great Topic and some very interesting information.

A key point for me in all of this is one Shane raises, I would say if we want to continue to improve it is importnat that no matter what level you build at you are always open to new thinking, I think when you look at most of the top builders this is a quality they posess.

A friend of mine wanted to purchase an instrument made by Stefan Sobel, a wise choice as Stefans guitars are of the highest order, he was looking at some second hand ones one was about 2 years old and one somewhere near 10 years old, he spoke to Stefan about which he should purchase, and Stefan said, buy the newer one cause he had improaved many things over that period, even when that first instrument was made Stefan had been up there for 20 years, this to me was a great illustration of why Stefan is considered one of the top builders.

To me as well this gives us another key advantage over the factories, if we find an improavement we can impliment use it straight off, imagine how difficult it is for say Taylor to impliment a change.

Another point that complicates the quest for perfect tone is the diverse nature of the market, people have such different ideas about what sounds good to them, take for example the very neutral tone of a Taylor and compare it say to the rich and complex resonant tone of a Lowden, polls apart but you will find people who love both.

Sprocket .. good points .. and you are right, even though these particular tops were not that stiff, they both had good tap response (I just dont tune anything, just tap to see what it does sound like). The thicker top cedar had the most amazing sustain in the rough at about 200 thou. I had no idea what the note was, dont really care, but the response was there all along.

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

[QUOTE=Kevin Gallagher]      
    I've read Bill's book and have given much of it deep consideration over the years, but am not a strong proponent of it as a great source for reference or instruction for the luthier in the real world. Sorry.   [/QUOTE]

Kevin, That is very surprising to me that you would say that. Would you not agree that Bill and Jon's book is the best book available? There are more resources today then when the book was first published, internet, DVD's/Videos, ect. but if you could only buy one book I don't know how anyone could say it is not THE book to buy.

I find it interesting that it is almost always referred to as Cumpiano's book and poor old Jonathan Natelson very rarely gets a mention at all.

Says something about keeping a high profile I suppose!

Rick - fascinating to hear that you are looking for clarity and sustain, as that's exactly what I am chasing when I "tap and fiddle". As I say, it all depends what you mean by "tuning".

"Tap tuning" - getting you bath to play a major chord as it fills up Dave White38821.4252777778

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010