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#1
10-05-2014, 03:12 PM
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Luthiers please advise on my concept
hello
I wish to ask other luthiers if its wise to continue on my endevour. I have spend over 10000 dollar to do research and developement of my own system, and unfortunatly my crowdfunding campaign failed to take it to the next level... I hope other luthiers with more knowledge and experience then me can tell me if i am on to something with this design or not, it`s pretty out of the box. failed campaign can be found here: https://www.indiegogo.com/projects/t...x/7621930#home For the last 2 years i have been developing a carbon fiber acoustic guitar with a unique design i call the loosetop system. This means that the edges of the soundboard are not attached to the sides of the instrument like in a traditional guitar. In prototype 2.0 the top was standing on legs that looked like an upright bass bridge, but now i am thinking of hanging the top on the tension grid, without legs. The string tension has been decoupled from the soundboard and given to a thing i call the tension grid ( the triangle shape thing), leaving the soundboard with only 1 function, vibrating. I am about 85% there, and i needed crowdfunding to do the other 15% ( need a 3d model, CNC aluminium molds) If i am to continue it will cost alot more money (which i dont have), and if the majority of professional luthiers thinks that it is absolutly requiered for the top to be attached to the sides,i might adapt my plan , and use my unibody (back, sides and neck in 1 piece carbon) and build regular soundboard on it and a fingerboard... For example the vibrational modes are completely different, since the edge is now free. How exactly i dont know at this point , since i need some scientists to analyse it. I have sacrificed alot to get to this point and now im completely broke, i have mailed luthiers and large companys for advice and/or a partnership and so far not even 1 reply. luthiers , please advise i hope this image makes the concept clear : 
Last edited by littlesmith; 10-05-2014 at 03:24 PM. 
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#2
10-05-2014, 08:11 PM
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I can see why you received no response, I ceratinly don't know what to say. I do not see what you are trying to accomplish, nor how, from looking at your pictures. I have spent my own career pushing the parameters of conventional guitar design, which yours does not appear to be, so I may not be the right guy. I do feel your pain.
CNC is usually viewed as a way to get repeatable results, not so much to create a prototype. I would advise cutting one of what ever you are talking about out of billet material with conventional tools. When the idea is proven and refined, and there are orders aplenty, then CNC might be the way to go on. My experi nice is that it takes a minimum of three prototypes to get anything at all whatsoever to work as it should. Or to be fairly sure that it won't.
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#3
10-05-2014, 08:57 PM
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How does one attach a drum skin to a drum that will allow the skin to vibrate and thus push air when struck. It doesn't make sense to me not to attach the skin on it's outer edges or to have the skin float or suspended in any way. A guitar works much the same way.
I can't understand what you are thinking. What is the theory, what is it you are trying to accomplish?
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#4
10-05-2014, 11:29 PM
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That's an awfully expensive experiment
 The concept doesn't make any sense to me, but if you think it still has hope, then keep at it.Reminds me of the Virzi plate used in some violins and things. Hanging it from the CF grid by 3 points like a Virzi would be a good thing to try. Maybe do some chladni testing to find good locations for the anchors. Glue 3 little wood blocks to the free plate and to your bench or something sturdy, sprinkle glitter or something on the plate, and play various frequency sine waves through a speaker to get it vibrating and see what kind of mode shapes you get for various anchor layouts. One thing to keep in mind is that any bracing should be done equally on both sides of the soundboard. If you use a wood plate with unconstrained edges, braced on one side only, it will potato chip quite dramatically when the humidity drops, and would need a lot of clearance to avoid contacting your CF grid. Not as dramatically with your western redcedar as it would be with spruce, but still significant. But without any tension on the soundboard, you could leave it completely unbraced, and just use thickness to change the vibrational behavior. Doesn't have to be the same thickness all over  My advice: Don't spend much more money on the project until you're sure it will work. Do lots of experiments, but keep them cheap or free. It doesn't seem to me like it would sound good, but most builders say a rosewood top wouldn't sound good, and that's what I'm working on... Always fun to try new things
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#5
10-06-2014, 04:19 AM
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Thank you for the responses, it is indeed a totally unproven concept. The campaign failed for a variety of reasons.
no real guitar player, bad sound, no marketing, product to expensive,no fancy video and so on The idea behind it was that Gregory smallman made his top edge very thin, with a hidden support construction, that gave me a flashback to my childhood when i put a ruler on the table and make it go boingggg. when you hold the other edge aswell, the vibration is less, but when its free it can vibrate very well. I think i will start using the unibody , and building a normal guitar with it. gluing the wooden strips in, gluing a soundboard on, routing perflings and bindings, and gluing a fingerboard. then along the way some experimenting. The problem with this construction is , you can not really open it up without cutting a hole in, as i experienced 1st hand, so if there is a 3rd prototype i need to have the soundboard replacable to test and finetune. dekutree64 : the idea was to hang the top on glued legs that are positioned in the most "dead" acoustic spots acording to chladni pattarns. Bruce Sexauer: the aluminium was indeed intended for production. my prototype mold could not handle the heat in the oven and warped.
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#6
10-06-2014, 07:28 AM
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#7
10-06-2014, 07:37 AM
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I want to draw sectors on the soundboard like that game batttleship A1 A2 A3 and so on. then i want to put the full spectrum of the guitar frequenties on it with a mechanical oscillator (chladni patterns). and take picture of the sand or salt from the topview with every note. Then i have to compare them all for active and inactive spots.
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#8
10-06-2014, 08:38 AM
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#9
10-06-2014, 08:40 AM
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what does it sound like?
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#10
10-06-2014, 08:51 AM
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As I understand it you want to suspend a top with the edges of it free to vibrate. First thoughts is that it might make for a fragile design, not a guitar you want to throw in the trunk and go to the beach. Next is that it reminds me of some of the Electric guitar players I have seen think they can get the back radiation of a speaker by cutting out much of the baffle to let the sound out. The problem is that the pressure developed at the back side of the speaker cancels with the difference of pressure in the front of the speaker. The speaker moves a lot, just not much bass action happening.
I see your top doing the same thing unless you seal up the sides in some way. You can keep a tight tolerance around the top to limit the amount of air getting pumped through the gap but that would require a good suspension system and tight tolerances of the wood top that can change dimension with humidity as already mentioned. In a way you are trying to build a dobro but use a wood top as the driving element. With a free top with edges not sealed you will get less efficiency helmholtz action. So less bass again, the free top may make for a louder guitar in the upper registers with the greater displacement the top. I can see it being unbalanced tone wise. Maybe you can use the free edges to your advantage and rather than have a sound hole have the gap act as your sound hole similar to an archtop. I think the edges of the top vibrating will make a mess of the hemoholz effect but I could be wrong. On using carbon fiber and needing to tool up for a prototype, as said just make the prototype out of common materials to test out your ideas. I am assuming you are not going for a live back in your design so just grab a piece of pine, router out or cut out the center with a bandsaw and screw a back onto the sides. If you need to get into the guitar a drill with a screw headed bit will have the back off in no time and you can open it up and seal it as many times as you need.  With the free top I am thinking you will be able to get impressive chladni patterns but the goal is to produce sound rather than patterns. I can not see this design working well. Guitars with floating bridges and the strings suspended by the tailpiece and dobros are in a way more closer to what you are trying to do. Might want to look at what others have done in that direction. Don't get hung up on the composite materials, they only make things lighter, common (cheap) materials are all you need until you can show good success in the acoustical properties of your design.
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#11
10-06-2014, 09:23 AM
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thank you.
I dont think its fragile, i used aero space grade carbon fiber, which was a mistake in the end, since it ate the entire budget. as you said , i should have made a prototype with cheap fiberglass. You live, you learn  I am a perfectionist and this is not the first time it has cost me, my first wooden guitar costs 800 euro (1000 USD) in wood and materials alone,which is absolutely not needed when you still have to learn everything. im pretty sure i could have build 4 guitars from that with beginners quality wood im just going to make hybrids with a carbon fiber unibody, and a regular top and fingerboard on it. with perflings and bindings, and experiment on the side. I cant keep spending without money coming in... Last edited by littlesmith; 10-06-2014 at 09:52 AM.
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#12
10-06-2014, 10:04 AM
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Not saying the CF is fragile, thinking of your soundboard. I am assuming it is lightly suspended, actually not sure how you have it done.
I worked on a project with a guy who got his ticket as a machinist, then got his mechanical technologist degree, then got his mechanical engineering degree. Some people on the project were keen to go for perfection, he said let's just make something to work and we'll make the second one better. When you are doing things that are new you may find that your ideas on how it should work and what you need to do to make it work are two different things. That is the reason for prototypes, going into production is a different story.
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#13
10-06-2014, 11:20 AM
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Last edited by littlesmith; 10-06-2014 at 11:28 AM.
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#14
10-06-2014, 01:40 PM
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Thomas Edison became the most successful inventor ever after he learned one lesson: am I solving a problem somebody wants solved? He'd built a machine that would automatically count votes in a legislature, with the idea of speeding things up. They didn't want it. Evidently they still don't....
Certainly everybody would like a more efficient guitar, but implicit in that is another requirement: it has to sound like the old standard. It's relatively easy to make one that's loud, but making one that's loud and also sounds 'good' (in the traditional sense), and doesn't have attendant problems, like 'wolf' notes, is going to be harder. If they just wanted loud, they could play solid bodies. As printer2 said, you're ignoring the way the 'standard' guitar works, particularly in the low end. They're built that way for a reason: it's the only way a relatively small box can produce any low frequency sound. Have you done any research on 'bass reflex speaker cabinet design'? You might find it helpful. You might also find a conversation with Tim White, the designer of the 'Chrysalis' guitar helpful. He ran into much the same sort of financing issues you have, and, so far as I know, is still trying to resolve them.
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#15
10-06-2014, 01:44 PM
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so i listened to the sound clip and to me it sounds like a ca cargo mixed in with an ovation with the form factor of an emerald, and a top that resembles and inside-out garrison. other then the promise of a possible theoretical novelty, what does this instrument bring to the table? what is sonically different about it that i can get nowhere else?
i can see that the edges of the cf honeycombing, unless totally sealed and radiused, will make it sharp and uncomfortable to play and will get full of dust and dirt and even then will not feel good to play on. fwiw, i'm not trying to give you a hard time here, but while everybody maybe saying "yahoo -go for it!, you still haven't been able to get it to to market. sometimes accurate critique helps one re-focus and can forestall years of struggling and rejection. i'm just trying to bring in a dose of reality here as i've seen several people waste large portions of their lives and every penny they own working on what might possibly be an impractical idea. best of luck!
Last edited by arie; 10-06-2014 at 02:00 PM.
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