Folded Horn Acoustic Guitar Patent # 10,777,172

It amazes me how such a "small" change can have such a large affect on the sound, wow! Maybe Art can model this again with these changes? 🙏
Also need to consider potting the piezo, the guitar did not feedback when playing, but if you leave you hands off it, and try your best to get it too feedback, it will. I am pretty sure a mic just can't be used in this situation, it would be a feedback machine. 🔊
Joe,

You could model your enclosure entering the actual volume and lengths of the various parts in Hornresp, as in the schematic in post #205, I can only guess as what the sizes or what your changes are.
You can then measure it using REW to see how it varies from the model.

Your design is in some ways similar to my Keystone "tapped horn" design, a Hornresp model won't exactly account for some of the variations in the orientation of the exits. Band-pass designs like this are good for low frequency output, but not for full range.

The gain before feedback will be reduced considerably (feedback will increase) when the pickup is in the same enclosure as the speakers, potting the pickup won't do much to reduce the loop between strings being excited by amplified resonance.
 

Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
Thank you much gents, my second patent for this guitar is worded as such: "The acoustic sound of the guitar is captured by a microphone, a piezo pickup, a pressure transducer pickup, a magnetic pickup under the strings, or any combination of these."

That should keep me covered for any kind of pickup I might use (or combination). More testing to do with pickups, even though I had good results from earlier tests with piezo's literally mounted approx. 4" away from the speakers, on the same piece of wood, no feedback. About 3" or closer, BAM feedback zone, kind of crazy. Feedback still worries me. At this point I think I have everything licked, except that.

Yesterday and last night I jammed so hard on this guitar, I don't think I have played like that in 20 years, was pure joy. I literally have a hard time playing a regular acoustic guitar now, just not the same.

Art I like your design and mine also, because I am looking for low frequency output the most. I think any acoustic guitar sounds just a bit too "tinny", likely due to so much playing on the highest strings, so give me the lows, the rich beautiful lows, but not too much!

JJ I like your idea about magnetic pickups, I have not tried that yet, it is time. Have you guys ever heard of the Helpinstill magnetic pickups for Grand Pianos? I know a guy that has this system, and it sounds great, no feedback, very interesting. I think maybe I mentioned this before. Stay tuned and thanks much as always for your help.
 
JJ I like your idea about magnetic pickups, I have not tried that yet, it is time. Have you guys ever heard of the Helpinstill magnetic pickups for Grand Pianos?
I have not used mine for some time.
The Helpinstill pickup system consists of three separate magnetic pickups and is a bit tricky to install on some pianos.

Since the pickups pretty much only pick up the string sound, isolation from loud stage gear and monitors is not a problem, and acoustic feedback is easy to eq out, and does not occur until monitor levels are shaking the harp.
Adding a condenser mic for a little more “real” piano sound can be helpful, especially on softer songs.

That said, I installed one on a friend’s early 1900 baby grand piano, and the Helpinstill output actually sounded better than the piano does acoustically- the pickup does not pick up some bad resonances and sound board buzzes.

There is an art to placing the pickups, and small placement differences make a big difference in the way the string harmonics are picked up, just like on an electric guitar or bass, and you have to commit to one location, so get it right!

Some pianos are built in such a way that the best position for the pickups is not possible due to location of harp hardware. Other pianos are a breeze, and once familiar the installation process can be done in a matter of minutes, and the results are great.

The single coil pickups are susceptible to RF(radio frequency) noise, grounding the piano strings with an alligator clip to the pickup shield and/or pin one is helpful.

For the most part, noise is not much of a problem, since the reason a Helpinstill is used is the noise level from guitar, bass, drums and monitors is already pretty high.

Charlie Helpinstill also made hum bucking versions for high RF noise situations.

Having owned and used the Barcus Berry piezo C-tape (C-ducer?) and the Helpinstill, I far prefer the Helpinstill for piano amplification in any rock situation. I bought the C-ducer back in the day to satisfy riders, but it never satisfied me without heavy reliance on mics, which defeats the purpose of a pickup.

Art
 

Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
Wow that is great, I also was amazed at how good that pickup sounded on the piano. I do have two magnetic pickups for acoustic guitar sound holes. I don't mind the way they look, but one had crummy very delicate electronics and they other one I don't remember why I didn't like it, will test again, and also purchase more to test. Now that the guitar sounding a bit more like an electric guitar is very encouraging to me, a magnetic pickup just may be the ticket. Plus the feedback issue goes bye, bye. might actually save my ***. Thanks guys! Joe
 
Yesterday and last night I jammed so hard on this guitar, I don't think I have played like that in 20 years, was pure joy.
Glad to read its bringing you that, if not yet $. Done right, I would think this to be a revolutionary instrument. One idea you might want to cover is making the two horns each of slightly different length, to cover chromatic notes about your current double 80Hz tuning. Thinking one horn speaks at low E in concert pitch, the other F# - or whatever you think, probably being a better musician than me. Some performers like to tune down to D, so I have to wonder what a D and E "speaking" horn combo would play like?

Dont let someone steal your invention via an "improvement" that ends up being actually more than marginal - perhaps. I keep thinking of ways to model the horns empirically for an idea such as this and the best I can come up with is the foam-core stuff that some here build speakers out of. You could have a replica cabinet with your two speakers and then foam-core horns of different lengths to see how that sounds. They wouldnt have to have all the bends as when fit inside the guitar, just to get the sonic gist of such an idea as two slightly different lengths simultaneously driven.
 
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Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
Thank you so much JJ, not pursuing $ as first priority is probably what is making this guitar so special. I am on a tight schedule at work, constantly trying to making $ (and we do), so enough, happiness comes first on this project. I also need to be careful about invention theft of course, but having a patent means everything is in the public domain. Any invention can be worked around by unscrupulous people I am sure, just not worth worrying about. Plus DIY Audio is full of music lovers, a great sign, but you never know where a patent troll will go. I have over 14,000 hits on this topic, so encouraging.

I have shared the patent and pictures/info of course, but all of this info will be part of my marketing plan, so it will be out there eventually. I am trying to market based on facts and quality, not fluff. What I will not share, and consider proprietary is the 3D CAD model, and the 2D working drawings (not patent drawings). I kind of want to share the drawings, they are full scale and 36" tall by literally ten feet long with all views included, but I must keep out of public view. This guitar can not be made without the 3D CAD model and detailed 2D drawings (every single dimension), and all associated programs and cutters required to manufacture.

I am intrigued by your idea of different horn lengths, but might not be easy to do, as the horns are the most complicated shape. Right now the horns are identical and the body is 100% symmetrical, which I believe to be very good, but certainly open to ideas. Thanks for your support! Joe
 
This guitar can not be made without the 3D CAD model and detailed 2D drawings (every single dimension), and all associated programs and cutters required to manufacture.
A guitar with internal curved paths could be made using "bendy plywood", flexible plywood made from several veneers that all run in the same direction, could duplicate yours using a small fraction of the wood used, and be built with standard hand tools and simple jigs.
The difference in materials (type, grain, density of wood) used even if made using your 3D CAD model could have more effect on tone than minor differences in construction between by hand or CNC.
I am intrigued by your idea of different horn lengths, but might not be easy to do, as the horns are the most complicated shape. Right now the horns are identical and the body is 100% symmetrical, which I believe to be very good, but certainly open to ideas. Thanks for your support! Joe
Different horn lengths would be no more difficult to build, and would smooth (fill in) the peaks and dips inherent in this type of design.
Using the front side of the drivers direct output would also fill in the high response (above around 1000Hz) attenuated in your design.
 

Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
I could move the speaker to the closest cutout in the horn to shorten the length, OK it is on my list, would be very interesting if I could measure the difference or actually hear it, but after the magnetic pickup testing!

Sure you could machine and bend wood, and make it using more conventional methods. If steamed correctly you can bend 1/2" thick wood, but you would still need my prints. There would be many pieces, many different sizes, much steaming, much bending, gluing and clamping, need to make jigs. I think it would take much longer, especially when manufacturing in high quantity for a business. The thickness is 1/4" minimum, much thicker and much more complicated than standard back and sides, much more work. Once you have the CNC program and all the bugs worked out, load the wood and let her rip, it can be unattended for most of the time, cuts at night, and goes fast. It is my preference for sure, but there are almost always different ways to make just about anything. Plus I like the strength and resonance of a solid piece of wood like mine, it is a beast. I know some of the old collectible violins were actually carved out of one piece of wood, back and sides one piece. Of course most were glued, not sure if the solid is more valuable. I would be willing to bet it will hold up better over time. Does glue affect resonance, not sure, would be interesting to research. The solid maple price is not bad for this type of a guitar. Maple is everywhere (hell there is some in my yard), it is a great tonewood, cuts well, very strong, and finishes well. I would not use anything other than a fine tonewood. Airplane wings are made from solid pieces, and literally 80% of material is cut away, happens all the time with CNC. Very fast, and very accurate. If your material is very high cost, that would be different.

As for patents, well just about anything can happen. Some people in "other countries" rip people off on a daily basis. Having a U.S. Patent will not stop manufacturing and selling in a different country, but will protect from importing into the U.S. Would I let somebody use my design (with permission) to build their own guitar, sure I would! Can't start a business and sell for profit, that would be an infringement in my view.

Could people change it slightly, and try to get away with it, people try it all the time. Sometimes they get away with it, and sometimes they don't. It is a risk for them for sure, bad idea. I would most certainly sue anybody that tried to steal my intellectual property, but I hope that does not happen. Thanks and keep the ideas coming! Joe
 

Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
Hello Art and JJ - this feedback test is very encouraging and surprising to me. 1/2" Baltic Birch will not feedback, even with a microphone! Not saying I can use a mic given the guitar enclosure, but it sure makes a piezo or magnetic pickup look like a great way to rock without feedback. You know the design and what I am talking about. I have heard enough. I think there is a private messaging option here, but I don't see it. My cell is 765-366-6773. I know this is free advice on DIY Audio, but you guys have gone above and beyond for me. Please send me your address, if you do not mind, so I can send you a check for consulting fees. Thanks! Joe
 

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Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
I tried another experiment, with my iPhone and The Allman Brothers Band "Stand Back" through the guitar horns, UNCOVERED, and put the Master, Gain, Treble, Mid and Bass up to ten, the sound of course was awful. I mean dogs would be crying in the streets, and old ladies would faint. Expected.

Then I put the 1/4" inch Baltic Birch on top of the horns as I did before, with the large opening behind the speakers, but never at these levels, and yes the bass went through the roof as expected, but distortion that would make anybody question the sound. Expected. Again at these high levels, never dared to do this before.

Then I put the 1/2" inch Baltic Birch on the horns, NO HOLE OR PORT, again amp MAXED OUT on everything, and the sound was incredible, no distortion that I could hear, wish I could see the speaker excursion, or lack thereof! I think this proves I could put even more power in this guitar. Let's Rock! Joe
 

Joe K

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2021-08-14 12:12 am
Indianapolis, IN.
Thank you PRR, have not heard from you in some time, any comments? I value your opinions, let me have it!

I had to reschedule just a few weeks with Ian at Chicago School of Guitar Making/Specimen Products, but I did have a chance to speak with him. He said my guitar was very intriguing, and he was looking forward to discussing. And why wouldn't he? He makes horns, speakers, amplifiers and guitars, and I have all four in the same product. ;) Seems like a very cool guy, can't wait to learn in his shop. Will start with a kit, then move on to my product, so this guitar is assembled, fit and finished correctly. Hopefully he can make a custom amp for me, that fits better, and has more power. :unsure: Check out his website if interested in these types of products.

I am also going to hit up Acoustic Guitar magazine for a story, but not until the product is complete, hope they are interested. I have subscribed for years, they showcase some beautiful products, especially from the small Luthiers that build their guitars by hand.

There are so many before and after options I could measure with the guitar and iPhone both, need to focus on that more, need more proof. Plus still need to do the sweeps, need more time.

Oh Yeah and the speaker fits perfectly in the horn opening about 7" away for the two different horn lengths JJ and Art. One would be 56% of the two combined, and one would be 44% of the two combined. I understand the goal, but not quit sure how different the lengths should be, would this be a good start? Thank you all for your kind support! Joe