Advice on my soundboard stiffness (Full Version)

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JasonM -> Advice on my soundboard stiffness (May 12 2018 23:14:05)

For what it's worth(not much) I tried to record the flexibility of my top: https://youtu.be/mIie1u097Eg

My intuition tells me this top is too flexible, but I also have nothing to compare to. It's at 2mm. I didn't intend to take it that thin but I had a second round with the rosette.

Edit: fixed the link. Also, i do have the long bridge patch in this plantilla to compensate, but again, the only reference I have for weight is to tap until I hear an F# [&:] I need a benchmark



Richard Jernigan -> RE: Advice on my soundboard stiffness (May 13 2018 1:07:08)

...link doesn't work...

RNJ



joselito_fletan -> RE: Advice on my soundboard stiffness (May 13 2018 1:14:56)

quote:

...link doesn't work...

RNJ


No worries fixed that for ya

https://youtu.be/mIie1u097Eg

[;)]



Richard Jernigan -> RE: Advice on my soundboard stiffness (May 13 2018 1:42:44)

quote:

ORIGINAL: joselito_fletan

No worries fixed that for ya

https://youtu.be/mIie1u097Eg

[;)]


Duh...

RNJ



constructordeguitarras -> RE: Advice on my soundboard stiffness (May 13 2018 12:00:44)

Yes, it looks like a very flexible top. It might make a guitar with the sound you want. It's a matter of taste what that sound should be. It also depends on how you brace the top. If it were my top and I was after the sound I like, I would brace it more heavily than I usually do. Although I have never used a bridge patch, in this case I might.

I would not rely on tuning it to a specific note, but that's just me I suppose. I don't believe that such a tuning has much meaning once the top is glued to the rest of the guitar. I do tap and listen to tops, before bracing, after bracing, and after building the guitar. But I am not listening for a specific note; rather I listen for other sound qualities.



JasonM -> RE: Advice on my soundboard stiffness (May 13 2018 15:31:17)

Hey Ethan thanks for the input. I don't know what kind of sound a top like this would produce, maybe not very bright trebles? but I sense it would not be responsive enough. I guess I would use the tap tone to give me some indication of how much extra mass to leave on the bracing, but I'm not sure I believe it's important either. at this point I'm thinking of getting a stiffer top.



Tom Blackshear -> RE: Advice on my soundboard stiffness (May 13 2018 16:07:58)

Jason,

I would suggest that you build the guitar, according to the plan, and then find out where you went wrong and right with it. You have quite a lot of information already.

Usually it takes me about 4 guitars when I'm getting into a new pattern. And the reason I suggested G-F# on the top tuning is that this was what Manuel Reyes did.

So when you get to the professional level of people like Ethan and Anders, etc.... then you can rest with the knowledge of doing your own thing.

I've built this plan with as little as 1.9 MM thickness.



JasonM -> RE: Advice on my soundboard stiffness (May 13 2018 17:02:30)

Tom, I know you said ~1.9 to 2.3 mm for a medium stiffness top. But maybe my top was on the lighter side of medium and I was shooting for 2.3. I'm a bit worried about the top yielding too much when finished. But if you think I should use it then I will push on.



Tom Blackshear -> RE: Advice on my soundboard stiffness (May 13 2018 18:51:41)

With the thought of having to build 3 or 4 guitars to get the feel of its priorities I would suggest that you carry on to see where the end result is.

I have replaced what seemed to be myriad tops in my past building schedules to find beneficial results, before I learned the fine tuning techniques.

The top may pump a little more air but that doesn't mean its a bad top.



JasonM -> RE: Advice on my soundboard stiffness (May 14 2018 14:47:49)

Well that makes me feel a bit better. I can't think 3-4 guitars ahead at the moment though! Thnaks again!



Tom Blackshear -> RE: Advice on my soundboard stiffness (May 14 2018 15:39:02)

On the other hand, if you don't feel comfortable with this one then build another top. It's all in the discipline of building guitars.

There is no set rule that says you have to stay with one set of measurements.

I give the 2003 Reyes style plan as a basic formula, not as an absolute. So keep it close but consider the wood type.



Stephen Eden -> RE: Advice on my soundboard stiffness (May 15 2018 7:50:35)

I won't be any help as to me feeling is more than seeing.

However you can see it from two sides. Start again and keep it thicker. You can always remove material from the top when the guitar is put together. Also good because there is little doubt you will mark the top during construction and will need to sand material off any way.

The other side. Having no reference point to how a guitar top should feel when thicknessed means you also won't know if it's just right. On that thinking build it any way and see for your self if the top is too flexible.



estebanana -> RE: Advice on my soundboard stiffness (May 15 2018 8:32:25)

I won't tell you how to brace it, or thickness it - tip on evaluation of flex. Cut out sound hole. Put one hand of fingers in hole, and the other on tail end. Put your thumbs under where the bridge goes. Push up gently with thumbs.

Try to understand the stiffness along the grain from first transverse brace to tail block.

That is critical. Side to side flex across the grain is important too, but without stiffness along the grain you're fu$$cked. If you are too floppy along the grain guitar tends to be un profound. Maybe loud, but probably weak in some way. The trick is to hit it just right along the grain, the cross stiffness had more to do with growl. Science backs that **** up.



estebanana -> RE: Advice on my soundboard stiffness (May 15 2018 11:00:36)

Let the force flow through your fingers Luke.

You may also want to gently plow your thumbs into the top and feel it, massage it across the grain. One thing to avoid is to have to thin the edges of the rim to get them true. That is a technical issue to be thinking ahead on.



JasonM -> RE: Advice on my soundboard stiffness (May 15 2018 14:25:01)

Stephen, now that is some good info on top flexing I could have used. That makes sense because I handed the top to my mentor (who builds steel strings) and I watched him put the top on the end of the workbench at the lower harmonic bar with a caul across and flex it. That's when i did an oh shot realizing I had lost stiffness there. Mentor doesn't pretend to know what makes a good flamenco top which is good.



estebanana -> RE: Advice on my soundboard stiffness (May 15 2018 14:44:14)

Stiffness on a steel and flamenco much different. There's something you can do if you come up too thin between transverse brace and tail.

I always call that a transverse brace, because I feel like calling it a harmonic bar is wrong on every level. I mean why not call it a harmonic pub? Right? It's so wrong.



JasonM -> RE: Advice on my soundboard stiffness (May 15 2018 20:11:21)

Definitely different animals. Well, the force spoke to me and I ordered another top. I mean it's the brains of the machine. Hoping I can reuse the rosette though. I know you don't like the term harmonic bar. I'll call it sideways stick.



El Burdo -> RE: Advice on my soundboard stiffness (May 15 2018 20:37:33)

quote:

Side to side flex across the grain is important too, but without stiffness along the grain you're fu$$cked. If you are too floppy along the grain guitar tends to be un profound. Maybe loud, but probably weak in some way. The trick is to hit it just right along the grain, the cross stiffness had more to do with growl. Science backs that **** up.


Ditto. That's some really useful **** right there, and a welcome departure from the 'you just have to learn to feel it' schtick, which although obviously correct, is useless for the neophyte.

Jason - I would have wanted to investigate the recuperative powers of heavier braces with that top being so flexible. That seems to be the second variable - flexible top, braces providing rigidity, but the balance?



estebanana -> RE: Advice on my soundboard stiffness (May 15 2018 23:01:26)

Keep the top intact, save it. Now you have a document that tells you what you now perceive to be too thin of a top. Keep it because later your ability to utilize it may change, and you have a live top to use as a direct comparison.

Ok later if you build with it you'll complete the cycle of comparison. This is how you cultivate intuition informed by practice or experience.

You can investigate strong braces later or even the strap braces that I use which I stole from Ruck's book.
But go with your gut feeling and see how right it wrong you are. It's a little of both- empirical data sets, in with muscle memory and intuition.

What it isn't - intuition vs. empirical.

Also don't forget the culo brace and the ugly brace. Muy importante.



JasonM -> RE: Advice on my soundboard stiffness (May 16 2018 16:04:19)

Good point



Tom Blackshear -> RE: Advice on my soundboard stiffness (May 26 2018 14:11:11)

Jason,

When building the 2003 Reyes plan there are a lot of things to be considered.

I have found that thin tops are harder to manage than thick tops, perhaps for the reason that thick tops carry more music and are easier to modulate or hide unwanted vibrations that can cause undesirable frequencies; but the builder who can manage thin tops correctly has a greater advantage toward creating something real special in the tone of an instrument.

And with these thin tops comes the necessity to adjust strut synergy to where things come together in a more even harmonic range. This is the reason I worked on developing a fine tuning technique to feather the fan braces synergistically.

One thing I noticed about the original 2003 Reyes was that the second string was a little piffy; not clear. This is when I thought about fixing this problem with my first replica of the original.

Naturally, I didn't fix the original due to the fact I don't adjust master builder's guitars.

It worked by sanding the top of the second brace, next to the outside treble, a little thinner toward the sound-hole. Then I had to relieve the third brace beside it just a little to bring the equilibrium together for the treble end.

This technique works for the bass as well, just follow the plan.



JasonM -> RE: Advice on my soundboard stiffness (May 26 2018 16:45:33)

Hey Tom, speaking of the fine details of the braces, I noticed that the 3 struts on the treble side are not in the exact same positions as the bass side. I noticed this when I was tracing the plan in autocad. It's so slight but I wonder if it was error of the human hand or a detail of fine tuning by positioning.

Thanks for the details on the refinements. I guess I'll worry about that when the time comes. I did start on a new top and I'm glad I did.



Tom Blackshear -> RE: Advice on my soundboard stiffness (May 26 2018 18:23:27)

The plan is all detailed with fine tuning.



estebanana -> RE: Advice on my soundboard stiffness (May 27 2018 14:00:55)

It's essential that the synergies infrapolate concurrently, thus allowing the sybergization of synergystical Gaia theory allow synergystical harmonic convergence.


It's the dawning of the age of Aquarius.



constructordeguitarras -> RE: Advice on my soundboard stiffness (May 27 2018 14:24:31)

Ah, now it becomes clear.



El Burdo -> RE: Advice on my soundboard stiffness (May 27 2018 19:24:17)

quote:

adjust strut synergy


makes perfect sense.



estebanana -> RE: Advice on my soundboard stiffness (May 28 2018 1:47:41)

When I was in graduate school for the soft headed subject of art we had seminar classes where a group of students and teachers get together for several hours and talk about our work in front of the group. The context of the talk could range from sociology theory to philosophy or linguistics, or any manner of jive that was supposed to be heavy and important. Students used any theoretical means to justify the work they did.

But that is the fault of how academe classes knowledge, there's an epistemology stratification in University and art doesn't fit into the category that has been developed for it. The demand that academe places on art to be discursive has leaked out and pissed on the rest of creative culture and still forces practitioners to elaborate on the work with fanciful verbiage thoughtfully strung together in a vainglorious effort to explain things that basically don't operate under the rules of spoken language.

What I gleaned over the six years I was in academic settings as a student and some time later as a teacher, is that oftentimes it's more productive and honest to just say I don't know.

It's more important to acknowledge that some processes of bringing an object to life are not explainable with language, because the process itself is an internal language which is unspoken. You can hint around using words to describe internalized creative process, but you can't explain it.


When it comes to guitars you get in a muddle of part empirical and part intuitive creating, the empirical part needs a control subject, like a science experiment. The internalized tactile language part is unruly and needs to be given space to do it's thing- it's not part of our rationalized intentions.

Words to explain a process like how guitar tops work don't mean anything unless they are spiked to some empirical framework with an established universal language. That language is vested in words that have absolute values, such as Helmholz, mode, pitch, pole, Hertz, etc. These words have absolute meanings and universally understood as reference points.

Systems of explaining based on internal intuitive language tend to be inaccurate and based on anecdote. Which is fine for the person who makes up that system, because it becomes a personal way of keeping tabs on the nonverbal language inside your own process. Sharing this with others and expecting the same result to occur in guitar making is mighty wishful thinking.

Even if you tried to make two identical guitars on the same plan you couldn't. Each one will have different sounds, and different trade offs of what works and what doesn't.

The problem is that guitar top bracing and voicing can't be transmitted by a rote formula because each guitar is slightly different, even built with the same plan. The rote approach of ' sand brace X or Y doesn't explain the situation or how the guitar works. And if one person spends a lot of time developing a word salad which serves to remind them about how their unspoken process works for them, the rote word salad might be the wrong food for the other person.

Each person who is not engaged in an empirical process has to listen to the unspeaking internal maker to draw the connections between internal and emperical or what is factually and universally known between us.

We're all different and the same rote signposts don't translate into good guitars unless they are rooted in some real evaluation based on the research we have on guitar acoustics. Even then the guitar is so complicated there is no global explaination for how it works. And probably never will be.



Richard Jernigan -> RE: Advice on my soundboard stiffness (May 28 2018 3:30:41)

quote:

ORIGINAL: estebanana

<snip>
Words to explain a process like how guitar tops work don't mean anything unless they are spiked to some empirical framework with an established universal language. That language is vested in words that have absolute values, such as Helmholz, mode, pitch, pole, Hertz, etc. These words have absolute meanings and universally understood as reference points.

<another snip>

We're all different and the same rote signposts don't translate into good guitars unless they are rooted in some real evaluation based on the research we have on guitar acoustics. Even then the guitar is so complicated there is no global explaination for how it works. And probably never will be.


From the standpoint of a 43-year career as mathematician, engineer and physicist, and an even longer career as guitar nut and luthier aficionado, I say, "Well said, Stephen."

Of the guitar makers I have read or listened to, the one who seems most to employ standard physics and engineering terminology is Alan Carruth. He has had guitar making students who were science or engineering students at M.I.T. I suppose that may be where he picked up some of the language. But Alan seems to have a natural inclination toward experiment, and a talent for settling guitar folklore issues by devising just the right experiment. He has done quite a lot of measurement related to the guitar.

My favorite quote from Carruth is, "Measurement can distinguish good guitars from bad guitars, but it doesn't yet distinguish good guitars from great guitars."

Just because language and measurement are ill suited to conveying the subtleties of sound and how to achieve it, doesn't mean that skilled makers don't possess valuable and detailed knowledge.

Jose Ramirez III had "mathematical" theories of guitar design. I put the word in quotes because, as far as I could tell, his calculations were nonsense. But Jose III was responsible for quite a large number of great guitars.

RNJ



Echi -> RE: Advice on my soundboard stiffness (May 28 2018 9:29:15)

In ‘92 I bought an old number of American Lutherie as at the time I was interested in the guitars of Kasha and Smallman.
In the same issue there was an interessing article written by Jose’ Ramirez III with topic the bracing pattern.
José wrote that he had been studying the theory behind the bracing patterns for a while since he arrived to the conclusion that a star shaped bracing pattern (probably what today we call a radial bracing pattern) should be the best performing one.
He then commissioned to one of his employee to build a guitar with the usual specifications but for the radial bracing pattern.
With his great disappointment the Ramirez guitar with the radial bracing pattern was said playing exactly the same as a a traditionally braced Ramirez guitar. Ramirez III arrived then to the conclusion that the bracing pattern is not that important or at least less important than other aspects.
Romanillos said something similar.
Just matter for thoughts.



El Burdo -> RE: Advice on my soundboard stiffness (May 28 2018 10:44:31)

I read Tom's post as describing the physical technique that had worked for him - it was a pointer. I don't think snide ripostes are ever funny, even in bear pits like forums. But what you subsequently say about attempting to account for the unaccountable is pretty much correct to me (insert Frank Zappa quote <here>), but it doesn't disallow that having some mechanism where the bracing accords with the nature of the top is also true - the word would be synergy.
Where is Norcalluthier? I found his measuring systems fascinating but we only seemed to get to veil #3. Maybe he's been leant on by 'the mystery police'?



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