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Posted

So i've looked at accoustic guitars as having this hudge design flaw... apart from certain models being very uncomfortable for my right arm.

1. to much glue, why are braces glued on? why isn't the top made from one peice of wood? like just a big slab of sitka spuce, and just rout away the excess wood to leave the top, and the desired bracing design?

YES the grain direction won't be ideal for some of the braces but will that really matter? maybe a new bracing design would have to be developed...

YES i know different types of woods are used to brace tops to get different sounds but would an entirely sitka spruce or cedar top sound that bad?

2. the back and sides should also be one peice of wood. granted this would have to be one monster chunck of wood. Make some jig to cut out the bulk of the wood to be removed so it can be used for something else... then rout out the excess wood from the back and leave just the bracing pattern you wanted, then rout the sides out of the same block.

This would mean there's only 1 or 2 glue joints for the entire body of the guitar theoretically letting the vibrations travel a bit better thru the wood?

With the right jig i'm pretty sure you could get the correct thicknesses for all the required peices, granted this would be much harder then glueing some peices together but i have this idea in my head that it may sound better and it just won't go away. so i'll probably try this even if you guys laugh at me, just wanted to throw it out here...

BTW the above is patent pending if it would actually work :D so no stealsies..

Posted
so i'll probably try this even if you guys laugh at me, just wanted to throw it out here...

:D

Still...go for it, I say. Why not? Other than the fact that you'll start with about 30 pounds of wood to make a 3 pound guitar...

Although, if you're still going to glue the top and back to the sides, then how much glue will you really be saving yourself? Just for the braces and the kerf on the sides?

Also, normally the back and side pieces are quartersawn, which would not be the case if you routed them out of a single block of wood. Does this introduce strength or stability issues?

Posted

no no the back and sides are one peice... you just glue on the top

the non quartersaw sides might have an adverse effect ya..

Posted

the problem i see with the back and the sides, if your touting away wood to such a thin dimension, firtly it way to expensive since your throwing 90% of the wood out. second routing or even cutting such thin boards (when it gets to that) is highly unstable, there's a chance that wood that then would break from the router or the router would rip some wood out. the first part seems ok but i doubt its easy to do at a home workshop, maybe a cnc machine?

so in conclusion its probably impossible to do at a home work shop, and the big companies that make guitars and have these machines wouldnt try this because it is to uneconomical, and cost more than the traditional way and is possible less stable/strong

Posted

There are a number of reasons it wouldn't work.

1. In regards to the top, you already answered your own question with the bracing. If you look at an acoustic guitar top, there isn't a single brace on there where the grain of the brace runs the same direction as the top. They all run either 90 degrees or at an angle. The exception to this isn in a classical fan bracing pattern where one of the braces in the lower body runs with the grain right in the middle.

2. Almost all tops have a slight arch in them, this is achieved with the braces, the arch even when slight, add's a TON of stability to the top to help keep it from collapsing, think about bridges and how the bracing underneath is done, a circle is the strongest shape, that arch really really adds a tremendous amount of strength.

3. With the back and sides, if you cut it out of a single piece of wood you would end up with the sides being mostly endgrain. The only place that would not be end grain would be the VERY direct side. This would allow for large amounts of moisture and drying to occur and cause cracking and splitting. Binding is put on an acoustic guitar for a specific reason, not just because it looks pretty, it is put on there to PERMANENTLY seal the end grain so that it will not split or crack.

4. The back has a significant arch to it, again this helps with not only stability, but it creates a more resonant sound chamber. You could I suppose route it, but good luck with a hand held router, and even with a CNC there would end up being so much deflection in the wood at some point you'd never get a nice finish.

5. The sides would have to be far thicker just to avoid the wood moving to much while being routed.

6. If you ever find a piece of rosewood big enough to make a back AND sides together, let me know, you'd probably be the first person to do so. If you did find a piece that size, as with all wood, the chances of finding a block that size that has no inclusions or imperfections inside the block is unlikely. Can you imagine routing away all that wood only to find a hollow inclusion running right through your side?

7. The tension created by bending the wood sides actually helps with the vibration, it makes a tighter sound, try tapping an unbent side and then tapping a bent side, you'll notice a major tonal difference.

8. by the time you find the wood, and route that much out, assuming all goes well, you will have taken more time than bookmatching, thicknessing, and bending sides, cutting braces, and gluing it all up anyway.

If you are using a good wood glue, and have tight fitting bonds, you will not lose any resonance through glue joints, or rather you will lose such a small amount it's not worth worrying about. Remember, a GOOD glue joint will never break, the wood around it will break first, if you use good glue, and have a perfect fitting joint, the 2 pieces of wood virtually become one piece.

Anyway, you're welcome to try it, but I can tell you in my experiences of working with wood and it's properties, it isn't going to work for you.

Posted
2. the back and sides should also be one peice of wood. granted this would have to be one monster chunck of wood. Make some jig to cut out the bulk of the wood to be removed so it can be used for something else... then rout out the excess wood from the back and leave just the bracing pattern you wanted, then rout the sides out of the same block.

This would mean there's only 1 or 2 glue joints for the entire body of the guitar theoretically letting the vibrations travel a bit better thru the wood?

With the right jig i'm pretty sure you could get the correct thicknesses for all the required peices, granted this would be much harder then glueing some peices together but i have this idea in my head that it may sound better and it just won't go away. so i'll probably try this even if you guys laugh at me, just wanted to throw it out here...

BTW the above is patent pending if it would actually work B) so no stealsies..

Just a couple more points of interest,

First, some kind of jig to cut out the bulk of the wood so it can be used for something else, but still keep the back and sides one piece? You can cut the perimeter fine, but how on earth do you plan to cut the bottom free if the sides are all one piece? Invent that tool and you won't ever have to worry about anything again since you'll be a billionaire. You need to come in from somewhere to cut the bottom free, otherwise you pretty much have to route out the excess.

End grain wood doesn't vibrate worth a damn, so in theory your one piece back and sides would sound worse because the sides would be almost totally end grain, hence no real vibration from the sound chamber.

Lastly, unless you've applied for a patent, the idea isn't patent pending at all, and I don't think you've probably spent the thousands of dollars it requires to get a patent, especially since you can't get a patent until you at least have proof of concept :D So, you can ask people not to steal your idea (and I don't think that will happen in this case) but it's certainly not patent pending (and yes, I know you're joking anyway)

Anyway, it would be very ambitious, but I'm pretty much 100% certain it won't work in the end.

Posted

i willsay that a proper tight glue join will not loose resonance... this is an ed roman thing :D think about it... dense glue, no pores, solid. wood grain porous, gaps between fibres. think of sound proofing, it works by having gaps of air and material to absorb the soundwaves. the soundwave enters, reflects of back surface, and is dissapated thru the air gaps and fibre combination.

glue isnt a problem!! besides think of the waste created by machining all the wood out!!!!

Mike

Posted

also ed:

i dont think an archtop would be as criticalas an acoustic, they have thicker walls etc... and are generally not as deep in my experience. the cavitys are shallower etc...

Mike

Posted

LOL wow lgm, thanks for evaluating my idea, gives me lots to chew on back to the drawing board for a better sounding accoustic i guess.

Posted

Hey Derek, I dig that fact that you are thinking way outside the box(actually it's more like what you can do to make the box better)...anyway, the reason we make acoustics like we do now is because it works. The best way to make the next guitar you build a better one is to know every detail of the last guitar you built. For example...how much deflection did the top have prior to bracing it?, what size were your braces and how many grains per inch were they? were the braces scalloped and if so how deep? There are thousands of variables like that, which you can record and use to help determine how you can make your next instrument better. You could just pick 20 to 30 variables to record and use those to analyze what your next instrument will be. Just a thought.

Posted

This Guitar has a one piece body.

Another company worth checking out is Cole - Clark Guitars

from their web site:

"At Cole Clark Guitars we precision manufacture guitars to provide the optimum in sound quality and playability. The fact that we use modern technology should not be mistaken for a lack of respect for past methods. Acoustic guitar making remained relatively unchanged from the mid 1850’s Martin “X” braced design until now.

The original “X” was modified in the early 20th century to accommodate steel strings, and the “14 frets clear of the body” design to give greater fret access arrived just prior to 1930. From then, not much changed. There have been a few excursions into alternate materials, “space age” laminates, odd shapes etc., but mostly acoustic steel string guitars have been made the same way for a long time. Players agree that timber is the material that sounds best, and timber is our medium.

We combine the benefits of an integral neck heel with an accurately tuned face and back for exceptional clarity and sustain. The integral neck heel, while held in high esteem, has always been difficult to produce well, which is why most manufacturers opt for the more accessible but less efficient dovetail joint, screws or dowels, all of which are more at home in the furniture industry. Our ability to accurately make the integral neck heel enables us to manufacture with incredibly tight tolerances and this allows accurate assembly of our instruments.

The violin makers of history understood the necessity of tuning the vibrating plates of an instrument ( the top and the back ). We carve our tops and backs to achieve the best possible sound, using CNC router technology for extreme accuracy. The results are instruments which perform like no others.

Part of the design brief for Cole Clark Guitars was to make a better acoustic guitar. We have achieved this, with Patented methods which we also apply to other acoustic instruments such as lap steels."

To me, the 2 biggest problems w/single piece construction are related in that one large piece of wood is much more suseptable to humidity and temperature movement than smaller pieces of wood glued together. This mean a guitar of one piece of wood would require more frequent action adjustments, and would have to be tuned more often. When the wood tries to move too much, it splits. This is the most fatal problem w/large pieces of wood. That's the trade off; glued wood is stronger, more stable, and last longer. Solid wood sounds better. :D

Posted

The concept of a one piece guitar body is a pretty cool one, although hard to build in an acoustic. Imagine trying to hollow out an acoustic from one soild block of wood :D It seems like the acoustics from Cole Clark do have bent sides.

These designs I like basically make the back and sides out of one piece and adding a separate top. This makes for a really interesting guitar design. For an acoustic electric it really is a blend of the two. I just finished a semi-hollow guitar built like this and it sounds great. I used a carved spruce archtop design with parallel bracing. I could have cut the braces into the same piece as the top but the carving would have been very difficult and the result perhaps not so good. I like to be able to tap tune the tops and then decide how stiff of a brace to use so I can adjust the sound a bit. For an x-brace, forget it. But for a parallel brace I would do it. The grain is still consistent with what you want in the bracing.

Here is an interesting example where the top and bracing is definitely carved from one piece: Specimen Guitars - Royale model process pic

What I like about the idea of making the back and sides from one piece is that you can approach the response and sustain of an electric while being able to hollow it out and get some nice acoustic qualities. Other approaches include having a center block left unrouted down the middle of the body or just chambering the sides heavily and adding an f-hole. Another that I want to try is to leave a block under the bridge to you can use a tune-o-matic and stop tail piece (or a string through). I haven't yet tried these though.

Posted

What I wanted to do was add some acoustic-ness to the electric guitar idea. So the thick edges were not seen as worse than the thinner acoustic sides but far more acoustic than the solid block was. It was a move from electric to acoustic and not the other way around, if that makes sense.

I think the trade offs would be less susceptability to feedback and increased sustain due to the larger mass of the body. I figured the spruce would take care of the acoustic tone and the open cavity would add to that as well. Everything else was designed electric style.

Using bent sides and a carved top and back would more like a 335 style guitar. I want to try one of those too.

Posted

I've recently purchased a Washburn EA17 and the body is only 3" thick and is made of maple laminate but I'm stunned at the tone and volume. No, it's NOT as good as a full size acoustic, the bass is lacking for sure, but it's fine for me to the point that my full size acoustic, which I discovered I never really got into 'cause it's so big, is now on ebay. :D

Posted

If you think of a speaker cabinet and how the sides and back have to be stiff so the speaker will respond to it's fullest, then having thicker sides in an acoustic guitar would theoretically be good for top movement. The issue with building one using the common method would be bending a thick piece of wood which you could conquer by bending 2 sets of sides and laminating them. Thats what a few high end builders I know are doing.

Posted

I see what you're saying, but it seems a solid guitar top would never move air at pressure rate near what a PA would. That asside, I want to make sure I understand your other comment. You're saying that a laminate side is preferred over solid? I'm not doubting it; it makes sense to me, I'm just trying to understand. :D

Posted

Torres is the Spanish luthier who set the pattern for classical guitar construction. At the time, there was a lot of debate about the importance of the construction of the sides and back. To prove his point about the dominance of the top/bracing, he made a guitar with paper-mache sides and back. It was said to have sounded very good.

Back and side construction have an effect on the sound of an acoustic, but, it's probably subtler. Most of the string energy and the largest displacements are in the guitar top. The body of the guitar is a resonator and the top is driving the volume of air. The primary job of the sides/back is to support the top, define the shape of the cavity, and help project the sound out of it.

The curved shape of the sides make them very stiff, compared to the top, and they vibrate much less. The backs are also stiffened with bracing and arching. The density, stiffness, damping, and mass of the sides and back affect their response... how brightly they reflect sound, what their own natural frequencies are and how that reinforces or detracts from the guitar's overall sound.

The material for guitar (and violins/cellos/etc) tops has converged on really light, strong, straight grained tone woods. Even on expensive instruments, sides and backs are made of other species of wood which are frequently chosen as much for their appearance, as their tonal properties.

BTW, I'm new to this forum. I recently stumbled onto the site. It's really cool. Some amazing and inspiring stuff is being done here.

Posted

I think laminate sides are probably no real loss for tone. I can certainly understand what a laminate would do to a top and see how it could affect a back, yet, of the 2 acoustics I own, one is solid all the way around and the other is laminate all the way around. The laminate is also only 3" deep and maple to boot, so it's quite weak on bass notes but it doesn't sound bad. I mean I've heard much worse full-size guitars that were just more cheaply made I guess.

Posted

Geez, there is as much speculation and theory surrounding this issue as any other. I have made my acoustic guitars with regular and reversed kerfing, the latter being way more stiff. The stiffer sides seemed to produce a more focused instrument which I like. The regular kerfing allowed the sides to move more and the tone was more mellow. Laminating the sides would probably make a really focused guitar.

The way I see is that each change and construction method produces tone. If you like it is good. If you don't it doesn't mean that any tone was lost or sucked away. It is just different. Hell, there are a lot of people that just love dreadnaughts and for the life of me I can't see why. I simply do not like the muddy and boomy guitar tone that dreadnaughts offer. It is the exact opposite of what I am trying to achieve with my own guitar designs and consequently I am passed up by a majority of the acoustic guitar buying public. That is how tone is.

Posted
i willsay that a proper tight glue join will not loose resonance... this is an ed roman thing :D think about it... dense glue, no pores, solid. wood grain porous, gaps between fibres. think of sound proofing, it works by having gaps of air and material to absorb the soundwaves. the soundwave enters, reflects of back surface, and is dissapated thru the air gaps and fibre combination.

glue isnt a problem!! besides think of the waste created by machining all the wood out!!!!

Mike

If we used that analogy, then lacquer would actually ADD to the sound of a guitar...

Posted
Derek, how would you tap tune the top?? Thats done prior to bracing....

I do not understand this at all. How do you tap tune an acoustic soundboard without bracing on it?

Every time I read about tap tuning or have a conversation about it there is always reference to tuning the soundboard after the braces are glued on while you are carving and shaping them. It is this that allows you to tune the top at all.

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