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Greetings and happy holidays. I had an idea for a classical guitar.

What If i were to take a classical guitar neck, and run 25" carbon fiber rods through and out of it, and mount the bridge at the end of those rods, making what is essentially a neck through design. The carbon fiber rods would act as bracing that would be holding the tension of the strings, and would allow the soundboard to resonate in a different way. I would still have some other bracing as well. My only concern is that the rods will run right under the sound hole on each side and could affect the sound, but I don't think this would be a big deal.

Can I have your thoughts, as well as any concerns on the design?


Cheers!
Nick

https://www.ebay.com/itm/Acoustic-guita ... XQd2hRYrDk

This is on ebay. It is a patent for guitar bracing, none of which I see as novel enough to warrant the patent, but who am I to say.

I think your proposal would deaden the sound, but I am just speculating.

Thats what im not sure of. the rods will as a brace, and will have active torque on them from the pull of the strings through the bridge. Theoretically these rods which double as a "Brace" should resonate better since they're holding the strings in place and may distribute the resonance throughout the soundboard better. However it could dead the sound. Its very hard to say. Theres nothing I can do but try it myself

You will be connecting any neck distortion to the top. Even in a classical guitar you get some folding up of the soundbox and neck. So I would think that would put a lot of stress on the top.

You might research Tilton's guitar patents. They do something similar, but in a simpler and more logical fashion. They were still not widely adopted even after the patents expired.

You might investigate how guitars make air move and then see if it's compatible with your idea.

"Theres nothing I can do but try it myself"

Hi Nick,
When I have a new idea, I solicit opinions, perhaps modify the idea from the information I have gained from them, and then try it. Sometimes it works out and sometimes it's a flop. It's possible the first iterations may not be totally successful, but through the knowledge acquired you may ultimately be successful. Even if it doesn't work as you think it will it may turn out to be something new and wonderful.

There plenty of archtops with a pair of braces that extend from roughly the neck block down past the ends of the bridge into the lower bout, and some of them sound great. Gibson did an "H" brace on flat tops in the late 20's that was similar. I have a very knowledgable friend who advised me not to use the "H" on an L-1 copy I was building because it really muffled the sound, although I have never heard one in person.

Ed

Archtops and flattops are very different beasts, and their bracing are there for different reasons and function differently.

Way oversimplified, a flattop has strings that twist the top where on an archtop they only push down. The bracing on a flattop also performs a bigger role in translating the strings energy to the top and shaping the sound. I am not sure how you will couple the neck/rods/top, whether energy will transfer, or whether the resulting top movement sans bracing will sound anything like a guitar.

That said, build it. It most likely won’t sound like a master built classical guitar. But it might surprise you.


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Just curious, how many classical guitars have you built?

Andy

rlrhett wrote:
"Way oversimplified, a flattop has strings that twist the top where on an archtop they only push down. "

Right, and the bracing is designed to control long-term top distortion under those different loads without (hopefully) killing the sound too much. The torque of the bridge on the top of a flat top does not seem to produce much sound power, although it can alter the timbre noticably. At least, that's what I found in my experiment.

I've seen some guitars over the years that have been designed to remove the static string load from the top, so that they could be made lighter by leaving off the bracing from a top of normal thickness. All the ones I've run into have sounded tubby and dull. It really does seem to me that the way to get a 'normal' guitar sound is to build a 'normal' guitar. You could get a more normal sound on such an instrument by making the top plate thicker, but that would add a lot of weight. That's why we use bracing. By the time you get it braced up to sound right, you've got enough stiffness to trake up the static load, so what the heck.

The way to get more sound out of a guitar is to reduce the weight of the top without losing stiffness. Keep in mind that all of the bracing on a typical steel string guitar top will weigh half or less of what the top plate itself weighs, and on Classicals it's even less. It's possible in a Classical guitar to have a bridge that weighs more than all of the other bracing put together.

Remember, a lot of smart people have been working on these designs for a long time. It's hard to make major improvments at this point. The folks that have succeeded best have done so by using new materials, such as Smalllman's CF/balsa lattice and the Damannn/Wagner use of Nomex honeycomb. Their designs are not universally acknowledged as 'better', although they have strong followings. It's possible to make improvements, but not easy.

There was a period about 35 years ago that Dieter Hopf was building classicals with a tail piece and the strings were just threaded through the bridge holes, rather than tied. This was to make the top super thin and hopefully improved. I no longer see Hopf guitars made this way and cannot even find old ones like this for sale. I am guessing that there proved to be something unsatisfactory about this.

If you are trying to make a guitar that can be amplified with less low note feedback, experiments like this could be interesting. I suspect the acoustic tone would have much less bass response.

Carbon fiber rods aren't very good for sound transmission, in my experience. I have used two 1/4" carbon fiber rods that reinforce the neck and extend out as braces for a floating neck extension (Doolin adjustable neck joint). The frets on the extension past the body join are pretty dead sounding. I would not use carbon fiber to mount a bridge. Of course YMMV. Good luck with it, whatever you decide to do.

_________________
Steve Smith
"Music is what feelings sound like"

There is a reason I asked this question. Classical guitar building is serious business, with a tremendous amount of effort, information, analysis, and luthiery behind it. Well more than any other guitar type. Some of the brightest minds have advanced the instrument.

So a precursor to "classical guitar ideas" is a background in what one has built and a corresponding reflection in comprehension of the scale of what's been developed to-date, by other luthiers. 95% of classical guitar improvements are incremental. Very very few and ideas out of the blue. 100 years of classical guitar development - it's just not how that works.

And to Mr. Carruth's point, one can design something better, but it takes hundreds of examples produced to fine-tune an approach. It is like Clapton's sound - it's not an idea, it's a life's work whose sound took a decade to develop. It's like people that have a "startup" idea ... the idea is 2% of the issue - 98% is the hard pain, twists, and turns, the really long hours, the patience and time to see it through.

To Steve's comment, for example, some classical luthiers are eschewing carbon fiber in the neck. Others are using pernambuco or other woods as enforcements. And even the discussion of bridge weights ... not all weight is bad. Classical makers care much about bridges - from weight to wood characteristics, and factors are often intertwined. There are those that send bridge stock to Brian Burns for testing. Then there is the lack of black and white testing ... take an approach, build 30-40 guitars that way, and a seasoned luthier gains some opinions which, unmeasurable, are still anecdotally informative.

Guitars are complicated instruments and in a lower energy environment of the classical guitar, especially with the traditional target - that it is to reach the back of a concert hall with clarity ... unamplified - their design and construction separates the wheat from the chaff.

Andy

"Classical guitar building is serious business, with a tremendous amount of effort, information, analysis, and luthiery behind it."

The beauty of being an amateur is you can put this on "ignore" and do as you please....

Clay S. wrote:
"The beauty of being an amateur is you can put this on "ignore" and do as you please...."

Sure, anybody, amateur or pro, can do that. The issue is not what you can or can't do, it's what you can do that's likely to work. The pros here are trying to help you figure that out before you do a lot of work.

There are two big problems with experiments. One is that most of them don't work. The other is that people tend to hear what they want to hear or expect to hear. The experiments you do are not very likely to be large improvements, but once you've put in all the effort there's a good chance you'll think they are. One of the hardest things about trying to improve the guitar, and particularly the Classical gutiar, is the likelihood that you'll hand it to some good player who will noodle around a bit and pass it back, and not be impressed. They usually try to say something nice, but it's along the lines of the response one person gave when asked if Elvis could act: "We're told he's very kind to his mother". Since, as Feynman said: "You are the easiest person for you to fool" you are also the last person you should believe when you think you've made a revolutionary improvement.

So, go ahead and do it: there's an off chance that it might work. Just don't believe it until somebody else (not you mother) says it did.
and don't spend the money you'll make from sales yet.

"There are two big problems with experiments. One is that most of them don't work."

Agreed,
I didn't mean to raise anyone's hackles with my statement, but rather point out that the Amateur need not have the same constraints as a Professional, who must meet an expected outcome. If I am building for someone else I will stick with the tried and true formulas, and with things that have worked for me in the past. When I am building for myself I may deviate from the path a bit, keeping in mind my past successes and failures. I once read that someone at Martin explained their "build by numbers approach (and not necessarily the right numbers) as working because eventually someone would like the sound of the guitar no matter how it sounded. This has worked quite well for them, in contrast to some who build "live for a day guitars", which may sound good initially but not hold up over time.
Guitar making for the hobby builder is only as serious as you want to make it.

98% of hobby builders have little clue what they are doing, especially when it comes to classical guitars, which is the subject of this thread. I don't think you are raising anyone's hackles. I'm just being frank on the subject, which I'm sure likewise won't raise any hackles.

Andy

This hurts to read because it is so true. The other one I would add is that just about every idea that might pop into your head has been done. Sometimes they'll even have a patent (and if you knew how hard some patents are to get, you wonder who those examiners doing musical instruments are ). And since you didn't know someone already did it, that is your answer at how broadly adopted and well liked by players it was.

I say innovate away! Experiment! Make what is already good very good! If you’re not tied down to making something to a spec then try new stuff .


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I have absolutely no idea how well it would work, but I stumbled across this picture a few days ago and thought you might like to see it.

I think the thing that most rankles me on posts like this (and we do see many of them over time) is that the posters typically have low post counts. Not very involved in this community. Its like a "get rich quick" scheme. Nothing good or great comes out of the blue. Its those who grind away at it endlessly that make the incremental improvements. I do, however, remain open minded.

" 95% of classical guitar improvements are incremental. Very very few and ideas out of the blue. 100 years of classical guitar development - it's just not how that works."

Smallman's and Dammann and Wagner's guitar designs seem somewhat less than "incremental" to me. Trevor Gore's falcate bracing I would also consider a radical departure from typical Torres fan bracing.

"98% of hobby builders have little clue what they are doing, especially when it comes to classical guitars,"

I would disagree with this statement. I think most of the "hobby builders" that are pursuing classical guitar designs have probably studied and researched the subject more than the average steel string builder. And aside from the person who puts together a kit for the experience of building - a - guitar, the average "hobby" steel string builder has a good understanding of what makes a good guitar. I don't think that guitar design is so esoteric that it can't be understood by most people that take an interest in it.
But perhaps I am biased. I consider most of the people posting on this forum (myself included) to be "hobby builders", which is not to say we aren't serious about building first rate instruments.

Alan C has probably done more experiments than even he can remember. Just visit his site to see. My own modest contribution to this thread comes from a builder who uses all man made products for his soundboards. I’m no traditionalist.

I don’t think anyone is suggesting it’s a waste to experiment or try to innovate. But those of us who have experimented have thrown a lot of guitars in the trash and put a lot of man-hours into unusable instruments. I think my tops have given me something I could not achieve with Spruce. But PLENTY of people have responded with “Meh,” or outright hostility. And that is after almost ten years of experimenting and refining. I have six guitars in buckets that were “almost”.

That is the experience I am trying to share. When someone posts that they have a radical build departure and want our help evaluating it, I try to share what it may mean in to try to build.

So by all means experiment. Build. That is what we are all about. But do it with opened eyes and sensible expectations.


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