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PostPosted: Mon Oct 29, 2007 11:21 am 
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Brazilian Rosewood
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There is always controversy surrounding Ervins methods etc.
I don't want to create any conflict but Paul B asked for a pict of a braced top like they are a secret.

I will show you 2 of mine.

One is from a flamed redwood topped cocobolo OM that I loved!!! (Top pict when not quite completed yet)
The 2nd is from an OLF SJ 12 string that I have had rave reviews over. It is the one that Graham Nash played
Very different bracing schemes!!!!! But I applied principles of his teachings to both tops in different ways

I hope this helps



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Excellent. Thanks Andy.


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PostPosted: Mon Oct 29, 2007 11:55 am 
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[QUOTE=azimmer1] .......But I applied principles of his teachings to both tops in different ways.....
[/QUOTE]   Those bracing schemes are your design, not Ervin's or anyones, they are yours right? Before the course would you have been able to do that? Would you have even tried?
That's so cool.

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PostPosted: Mon Oct 29, 2007 11:56 am 
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I've been keen to see some of your work since you wrote about Ervins course a while ago.  Very nice.  Very interesting.  Thanks for showing us.

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I don't know Ervin but hear great things about his work.

How about a few comments on what I see in this bracing scheme you have going here Andy? Just observations, no critique. We all appreciate your work and enjoy your posts and scrumptious pictures.

Observations:

1. Thin braces, somewhat knife-like
2. Indian Rosewood bridge plate, fairly quartersawn
3. Capped x-brace
4. No scalloping on lower x-braces or tone bars
5. Finger braces are skewed to more naturally divide this area (not 90 degrees off the lower x-brace and parallel)
6. Upper transverse brace is sculpted swooping off a higher center area, then a rapid concave cut near the lining
7. Two variations of lower bout bracing, the first more standard but with a type of two fingerbrace off the single tonebar, the second incorporating some lattice type system, apparently not interlocked as at the x, it's hard to tell

Thanks Andy for sharingBruce Dickey39384.858912037

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Thanks for the pics, Andy.
Interesting stuff.

Cheers
John


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PostPosted: Mon Oct 29, 2007 1:10 pm 
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Cool Andy,

Thanks for posting these. That spruce top looks pretty nice!!

It is just good to see you posting pictures again as you did pre-Somogyi. Of course lots will now ask you to talk about it but that is totally up to you. For me, I am just thrilled to see you experimenting.

Shane

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Onya Andy you da man!


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PostPosted: Tue Oct 30, 2007 3:02 am 
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I hate to admit it, but I would really love to take the Somogyi course. I'm pretty sure there's a whole lot more going on there in Andy's guitar tops than just the bracing pattern etc., and I'd love to get inside the mind of someone like Mr. Somogyi who has really thought this stuff out and tested his theories over the years.
Pictures are great, but there are so many variables that pics alone won't tell the whole story. I think that's part of what Brock and the others have been trying to say. There's just too much going on to give it adequate explanation without going back and quoting word for word what they learned in the course, and also having folks repeat the same experiments that they did in the class. In short...it's easier to pony-up and take the class by a long shot. I only wish I had the money to do it!

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PostPosted: Tue Oct 30, 2007 3:28 am 
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Thanks, Andy. I know Ervin's not teaching you how to brace, but how to
think about the goal you have for a guitar and develop solutions that
could achieve it---something much more powerful, flexible, and
extensible. What were your goals for these, and why did you make the
decisions you did?


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"I hate to admit it, but I would really love to take the Somogyi course"

I don't hate to admit it! I WOULD LOVE TO TAKE ES' COURSE!

Don is right, from my talks with Brock, I have the understanding that there is so much more to understand than just plate thickness and brace patterns.
If I could ask for one thing to come of a class like his, it would be the ability to set a target tone and hit it dead on.
I have loved the sound of every guitar that I have made, save for my #3 which was over built. And for the most part I have come close to my target tone each time. But it has been 1 part experience, 3 parts luck with a dash of "Do it this way and it will sound like a guitar" thrown in for good measure.
With each one I am adding to part 1 and taking away from parts 2&3. I feel pretty good these days.
--BUT--
To be able to aim, shoot and hit it out of the park each time would be awesome. Heck it might be the single most important tool that I would have in my shop!

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PostPosted: Tue Oct 30, 2007 3:58 am 
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A lot of my approach is based on basic engineering principles. I never understood the concept of fat braces. The cube rule is so revealing. Also I don't understand the purpose of scallops. A lot do it but it makes no sense to me. Think about how the stiffness changes in the area of a scallop. cube rule in reverse.

Steve Those bracing patterns are mine based on principles that I learned in Ervins class about how a top moves etc. Clearly they are not Ervins. He would be embarassed by my tops. I am trying new things with each guitar. Before the course I would have never tried these different things because I had no knowledge or foundation upon which to create new ideas with some sort of reason behind them.

Hesh I don't use a router. I either shape them on the guitar top with a chisel or pre shape them a bit with my belt sander first. Yes my sides are doubled. I use lower grade EIR for the inside and I dye it black so not to conflict with the back and sides. I like the look of the black sides.

Shane Beautiful Spruce of course...it is yours!!!!

My goals are a balanced moving top. I love the deep tones of a lightly built guitar. That is my preference. it may not be yours.

Ervins teachings give you a foundation upon which you can head in any direction and have a rational plan to achieve it. He doesn't want us to make guitars just like him. What is the point of that (His guitars are nice though)Before his class I didn't have a clue. It was like trying to write a novel without speaking the language. You build from a plan and then what???? You learn a ton about wood structure and top function and dynamics. We looked at tons of bracing schemes from Kashi to ladder. We dissected them to understand how they worked and why some were very successful and some were not. Each guitar is built for a particular reason. In the class we were give assignments to come up with a design based on player requests. Then we had to justify our design and take criticism. An example might be a Parlor with profound base and longer scale. 12 fret. Many were what seemed ridiculous but learning how to think and create a guitar that meets the goals of a customer is priceless.

Make sense?

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PostPosted: Tue Oct 30, 2007 4:13 am 
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Think about how the stiffness changes in the area of a scallop. cube rule in reverse.

And that's why we do it. Scalloping is a calculated weakening of the brace. And it's done in a softly scalloped shape which doesn't leave stress risers which could/would lead to the brace splitting.

Those who say they do it for mass removal don't yet understand it. plain and simple.

that said, some of my favorite guitars have bee non-scalloped, also(yes, i don't scallop each one). But it's a completely different tone and overall voice.

Andy, I like your last paragraph, above. I've not taken his course(though i'd love to if there's a hidden philanthropist lurking <bg>). It describes what seems like a well thought out method that teaches you to learn by study, instead of a "here's how I do it" manner.



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Mario
Clearly you understand the cube rule and what a scallop does. I guess the bigger picture is what changing the stiffness in particular areas of a brace and therefore the top does to the movement of the top and the creation of the sound.

Does having a freer more flexible section improve tone???
How does a top REALLY move in the creation of tone????
What changes in top design alter that movement??
Do those changes in top movement actually make a difference in tone?
These are the big questions.

I Don't have the answers but I have an opinion. I don't know if it is right or wrong.
My premise is that a top is more like a drum head. I want a symmetrical gradual change in stiffness. So I build that way.   Just my understanding whether right or wrong.

There have been tons of guitar built with scallops that are way better than mine. The bottom line is that with the massive changes in stiffness that occur with a scallop it doesn't make sense for me. I like the tone of a lightly built guitar. It is the voice I try to achieve. You can get there from many directions. I like thin tops and lighter braces to achieve this. So I don't want scallops. It works for me for MY understanding of top dynamics.   

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[QUOTE=grumpy] Think about how the stiffness changes in the area of a scallop. cube rule in reverse.And that's why we do it. Scalloping is a calculated weakening of the brace. And it's done in a softly scalloped shape which doesn't leave stress risers which could/would lead to the brace splitting.Those who say they do it for mass removal don't yet understand it. plain and simple......[/QUOTE]
I don't understand it.
Why do people scallop?
I have never heard a reason other than that is what Martin started many years ago and many have copied Martin because it works.
I'd love to hear a reason why creating massively stiff portions on a brace makes any sense at all.
What tonal/structural properties do they impart that make them a good idea for a guitar?
I don't have a clue.



[QUOTE=grumpy] .......It describes what seems like a well thought out method that teaches you to learn by study, instead of a "here's how I do it" manner.
[/QUOTE] That is exactly right. That's what I liked about it. It did frustrate some attendees that just wanted to be told what to do. Ervin would not answer a question like that directly, but take the person asking the question back to the basics principles of wood and design and help guide him on how to think about it. Ervin is a good teacher.

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PostPosted: Tue Oct 30, 2007 5:57 am 
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One of the interesting things we did in Ervins class was that we made models based on the the braced tops we brought to class. What we did was create a model to SEE stiffness.
It was eye opening. Most people understand the cube rule but really don't have a mental picture of what it really means in real life.

So we took our tops. I used one that I brought in and we picked a unit for size   Then based on the cube rule we converted that to stiffness. We then made foam tops representing the stiffness in our actual tops. It was eye opening to see how the stiffness was changing in the top I brought.   MASSIVE peaks and valleys. Try it some time on one of your tops.

This lesson is hard to describe but you really have to see it to believe it. I will look for a picture.

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PostPosted: Tue Oct 30, 2007 6:03 am 
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Here is a Steve S playing my worst guitar. BUT
look at the arrow. It shows a foam top somewhat representative of a typical top showing stiffness.

Interesting


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PostPosted: Tue Oct 30, 2007 6:30 am 
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There's also a plywood model representing brace stiffness on the wall behind the foam one.  That one may be easier to see.


And don't miss Ringo's cardboard Picasso guitar player behind Steve!


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PostPosted: Tue Oct 30, 2007 6:31 am 
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From what I've learned about teaching philosophies, Ervin is a
constructivist. The idea behind constructivism is that we're always
constructing knowledge, and the role of an educator is to faciliate that for
the student rather than constrict and define what that student will learn.
It comes through lots of question asking and teaching concepts rather
than algorithms. Questions like, "how could you solve this?"

Jean Piaget came up with the idea that we need to help people become
innovators rather than leading them to resemble the typical adult of our
society. Ervin referenced Piaget's stage theory in an article on his
website, so I wouldn't be surprised at all to see if the way he teaches is
influenced by him.


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PostPosted: Tue Oct 30, 2007 8:04 am 
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I'd love to hear a reason why creating massively stiff portions on a brace makes any sense at all.

What you just stated there is the opposite of a scalloped brace. A scalloped brace is weakened one, weakened in an area in order to allow the top  to move more freely.

If you're referring to the peaks left after the scalloping, they are used to control stiffness, and to create a node, a near-node(is that a word? but I think you should understand what I'm refering to) or to move a node. And again, the gentle sloping in and out of the scalloped(weakened) area is to prevent a stress riser.

No mystique there, and it's well understood. We're definitely NOT copying just for the sake of copying. Many an engineer(myself included) has studied brace patterns and shapes, and come to the same conclusions. CF Martin wasn't stupid, and it wasn't a fluke. It's a proven method to achieving a certain tonal goal. To completely dismiss it is to severely limit ones tone-shaping toolbox.

I am sure Ervin must have covered this kind of stuff. In order to understand why a straight brace can work well, one should also need to understand why a scalloped or tapered one also works. And one should know and understand what the tonal advantages of each, is.



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PostPosted: Tue Oct 30, 2007 9:05 am 
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Andy,

Thanks for sharing. You make me feel better about my current first guitar top bracing. Mine is pretty lightly braced but looks a great deal like yours. I have tried to pay attention to what I read and hear about bracing and what Somogyi says. John Mayes DVDs has been usefull too because you can see him work the top as he explains the issues. My Lutz top is STIFF and I have brought it down to about .100 with bracing that looks similar to yours. I was thinking the bracing could be a bit too thin but I remember everyone saying that they overbraced at least their first few guitars. Even though the bracing appears thin this top is still pretty stiff but is getting a better tap tone.

Thanks for showing the examples of the top stiffness in 3d. Very interesting! I don't have a clue on how you do it but I can see the result of the concept and its goals.

Thanks for sharing

Philip

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PostPosted: Tue Oct 30, 2007 10:47 am 
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[QUOTE=grumpy] I'd love to hear a reason why creating massively stiff portions on a brace makes any sense at all.What you just stated there is the opposite of a scalloped brace. A scalloped brace is weakened one, weakened in an area in order to allow the top to move more freely.If you're referring to the peaks left after the scalloping, they are used to control stiffness, and to create a node, a near-node(is that a word? but I think you should understand what I'm refering to) or to move a node. And again, the gentle sloping in and out of the scalloped(weakened) area is to prevent a stress riser. No mystique there, and it's well understood. We're definitely NOT copying just for the sake of copying. Many an engineer(myself included) has studied brace patterns and shapes, and come to the same conclusions. CF Martin wasn't stupid, and it wasn't a fluke. It's a proven method to achieving a certain tonal goal. To completely dismiss it is to severely limit ones tone-shaping toolbox.I am sure Ervin must have covered this kind of stuff. In order to understand why a straight brace can work well, one should also need to understand why a scalloped or tapered one also works. And one should know and understand what the tonal advantages of each, is.
[/QUOTE]
I don't see that you answered how do massively stiff portions on a brace make any sense? Yes I am referring to the peaks. Wouldn't those peaks create massively stiff areas on the soundboard when compared to the rest of the brace and the soundboard? I can't imagine why that is a good thing.
Calling it a node doesn't help me. Why would anyone want nodes on a guitar soundboard?

The gentle slope of the peak is gentle in looks only, but in terms of stiffness, it is anything but gentle.

I did not intend to, nor do I think I implied that CF Martin was stupid, or that his instrument were flukes. I said that his instruments work. Please don't put words in my mouth, it can make me grumpy.   

Maybe some builders aren't copying for the sake of copying, but many are. Either to create similar tone of a Martin, or just because that's what everyone else is doing. I have no interest in creating the Martin tone. There are plenty of those instruments around.
If you use scallops, why do you and how do you use them?

If you carved the scallops off a guitar, what changes would that produce?

In my very limited experience, scallops are a tonal disadvantage. The guitars I have made without scallops sound better to me that the ones with scallops. There are of course other differences as well, so it is not a completely fair comparison. (That is of course just to my ear and YMMV.)

I'm just trying to understand here, not argue. Please don't take offence at anything I'm saying or asking. I'm just trying to learn.
If you or anyone can explain exactly why or how a scallop works, I'd really appreciate it.
Thanks!

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PostPosted: Wed Oct 31, 2007 1:51 am 
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I have more experience as an engineer than as a luthier...so here's my take on this subject from an engineering perspective.

I think the functional purpose of the guitar body is to accentuate those frequencies throughout the whole range of sounds that the guitar creates. If you just wanted one note out of the guitar you would make the shape much more "regular" (either a circle or a square, or some other finite shape). By making the guitar the shape that we do, and bracing it as we do we create a variably stiff structure that is able to accentuate a whole range of tones. Things like scalloping the braces are just one more factor that can cause variation in the mass/stiffness characteristics of the soundboard...and as such it's just one more thing to throw into the mix. It will surely affect the tones...but how much and how are dependant on the rest of the structure as well as the individual pieces of wood.

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PostPosted: Wed Oct 31, 2007 2:31 am 
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SteveS...and other engineers...

Top bracing has two completely different functions:

1) Structural...to resist string pull and to maintain a reasonable semblance of the designed shape

2) Mechanical tonal shaping...EQ, if you like.   


You have to try to separate the functions in your mind to understand all that's going on.   If you look too closely from only one point of view and push it too far, you'll either have a wonderfully strong guitar top that sounds like crap, or you'll have a wonderful sounding guitar that blows up in your face.

So think of scalloping as EQ'ing the guitar top's response in one particular way.   It tends to emphasize lows and highs and because of how it allows the top to "break up" into phase/antiphase motion in the midrange, you get the familiar "smiley face" EQ that a lot of folks like to apply to an undersaddle pickup signal in order to better match the acoustic sound of the guitar.

Guitars without scalloped braces tend to have more midrange punch...which I happen to like.

Just my experience...


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