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  #31  
Old 02-15-2020, 05:04 PM
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Tim, I have no experience with sassafras. But I agree with the need to get that back musical. Interesting in your approach to thin and laminate with mahogany. You have me intrigued enough to follow along. I have some highly figured sapele that when tapped pretty much sounds like cardboard. If folks were to sort through my tonewood blindfolded, tapping sets as they go, these sapele sets would probably never be chosen. Once properly thicknessed and braced, though, the sapele has a sound that rivals its looks. One would never now how dull the unjoined plates sounded.

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  #32  
Old 02-16-2020, 07:36 AM
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Steve, your sassafras is very eye appealing. I have a little different approach I plan for him to give the back and sides. It will make a debut at the Artisan show in Harrisburg, PA in April.

Dennis, I agree. It's time to push into the next direction. You can get ready to hear from us much more starting this week!
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  #33  
Old 02-16-2020, 07:43 AM
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Quote:
Originally Posted by Neil K Walk View Post
Hi, Tim,

I’m glad to see you “back!”

Sorry, Dad joke. I couldn’t wait until June.

Speaking of which, will this have a double back? If so, what would the inner back be? I agree that the back gets muted when you “hug” the guitar but I thought your double back design addressed it.
Neil,
You crack me up. Thanks for the welcome back too.

I considered doing a "Hollow Back" but I already knew it would work and since I had scheduled these two builds specifically for R&D I wanted to get this "Reecho" idea out of my head and test it in real wood.






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Originally Posted by Kenneth Casper View Post
Tim, I have no experience with sassafras. But I agree with the need to get that back musical. Interesting in your approach to thin and laminate with mahogany. You have me intrigued enough to follow along. I have some highly figured sapele that when tapped pretty much sounds like cardboard. If folks were to sort through my tonewood blindfolded, tapping sets as they go, these sapele sets would probably never be chosen. Once properly thicknessed and braced, though, the sapele has a sound that rivals its looks. One would never now how dull the unjoined plates sounded.

Ken
Hi Ken,
I totally agree that most of us (luthiers) have made some pretty good sounding guitars with less than spectacular sounding woods that we started with. However, it sure increases our odds of making those truly special sounding guitars when we start with the absolute best materials possible. Regardless, who doesn't want a bit of luck on their side anyway, right?

Laminating was something else that I had as an idea for the back plate but never put to practical use before so why not try it on this R&D spec guitar? This wasn't a true laminated back in the sense that each ply of wood had the grain running 90* to adjacent layers. The typical alternating grain "plywood" laminate stifles the way vibration waves move along grain lines because those opposing layers act more as nodes or dead spots.

My back laminate works much the same way as my double sides do with the second ply of wood with its grain lines running in the same direction as the adjacent layer of wood. My Double Sides, when tapped, ring like a bell and I hoped for the same results from the back using the parallel ply method. My hypothesis was that with two "plys" with their grains running in the same direction, would have far less nodes and increase the resonances of the laminated plate.

After I glued up the back laminate of Black Heart Sassafras and Honduran Mahogany, I tapped the plate and to my pleasant surprise the tap tone changed dramatically, for the better. I then knew I was onto something but keep in mind that this was only a sample size of one, so I am not shouting total success from the roof tops ... just yet. Although the new laminate tap tone was certainly an improvement over the tap tone of the single plate of Sasafrass I was hopeful that there was still room for more improvement.

Enter the "Reecho project". Stay tuned for photos and full disclosure of the project ... very soon.
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  #34  
Old 02-16-2020, 08:18 AM
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I remember this piece of wood. Always loved it (visually).

I'm really worried now that you'll build yet another guitar that I just MUST have.
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  #35  
Old 02-16-2020, 10:04 AM
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Hi Tim, Mary. I understand the effect of dampening a live back and that your hollow back construction allows the inner back to resonate freely. It never occurred to me to think about the radiation off the back with your system. Does your outer back (for lack of a better word) vibrate or do you make it a 'reflective' or 'passive' back? Does your outer back contribute to the sound?
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  #36  
Old 02-16-2020, 10:51 AM
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Smile Open tunings...

Neil K says:

"From a player's perspective I think that's why I like open strings better. Tuning the strings to open G is especially hypnotic because the lack of any obstruction just seems to make the guitar sing "ohmmmmm!"

I agree!!! Open D for me... the ability to get in Just Tuning (one key only)as opposed to the usual tempered tuning which has been smoshed out of perfect tune in any one key to work in ALL keys, is quite magical sounding. Think barbershop quartet or do-wap acapella in PERFECT harmony.

I would assume something similar occurs when all the parts of the guitar vibrate in harmony.

John K's last three for me have no truss rod at all. Neck on the new one (BIG GUN) has a hollow Carbon Fiber D Tube, and the OVERLORD and Brown Bomb have a neck full of CF rods, from end to end.

Thanks Tim and Mary for the input to JK for the CF struts that free up the top .

Always more to learn and your posts are SO INFORMATIVE

thanks and have FUN

Make a Joyful noise indeed!!!

Paul
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  #37  
Old 02-17-2020, 06:11 AM
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Quote:
Originally Posted by SongwriterFan View Post
I remember this piece of wood. Always loved it (visually). I'm really worried now that you'll build yet another guitar that I just MUST have.
Sonicly though, it was a total dud, right? Be careful though and never say never David




Quote:
Originally Posted by printer2 View Post
Hi Tim, Mary. I understand the effect of dampening a live back and that your hollow back construction allows the inner back to resonate freely. It never occurred to me to think about the radiation off the back with your system. Does your outer back (for lack of a better word) vibrate or do you make it a 'reflective' or 'passive' back? Does your outer back contribute to the sound?
Hi Fred, Good question. The outer back, in our Hollow Back design, is mostly a non contributing participant. It plays no part in the role at all, as far as I can tell.







Quote:
Originally Posted by Guitars44me View Post
Thanks Tim and Mary for the input to JK for the CF struts that free up the top. Always more to learn and your posts are SO INFORMATIVE. Thanks and have FUN. Make a Joyful noise indeed!!!
Paul
Thanks Paul. We are always glad to help and share in any way that we can. Lets just hope that all of us old dogs remain open and willing to learn some new tricks. I know that I try to remain
optimistic though at times I'll admit it does make me stumble.
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  #38  
Old 02-17-2020, 03:15 PM
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Be careful though and never say never David
I will *never* own a dreadnought with a Florentine cutaway.

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  #39  
Old 02-17-2020, 07:14 PM
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I remember this piece of wood. Always loved it (visually).
Yep, I've drawn that sassafras from the vertical bin a number of times myself. I've drooled on it. I've lusted after it. And I've tapped it and, just because I'm not an expert, had Tim tap it.

Corrugated cardboard.

But doggone beautiful corrugated cardboard.

Let's hope the re-echo re-animates that piece of lumber. What top are you putting on it, Tim? And will you laminate the sides with hog, too?
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  #40  
Old 02-17-2020, 08:11 PM
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Hi Fred, Good question. The outer back, in our Hollow Back design, is mostly a non contributing participant. It plays no part in the role at all, as far as I can tell.
Now you got me itching to see what would happen if you had a lightly braced outer back to go with an iner back. Probably easiest to take a finished guitar and add a 'gasket' and plate to it. Now if I was not working on a dozen projects already (and that is how I get to a dozen, the old 'what if'). Looking forward to seeing Mary take pictures of you holding a pose over the current beauty.
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  #41  
Old 02-18-2020, 05:52 AM
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Quote:
Originally Posted by SongwriterFan View Post
I will *never* own a dreadnought with a Florentine cutaway.

There's wisdom in that phrase ... Never say never ...






Quote:
Originally Posted by Eire View Post
Yep, I've drawn that sassafras from the vertical bin a number of times myself. I've drooled on it. I've lusted after it. And I've tapped it and, just because I'm not an expert, had Tim tap it.

Corrugated cardboard.

But doggone beautiful corrugated cardboard.

Let's hope the re-echo re-animates that piece of lumber. What top are you putting on it, Tim? And will you laminate the sides with hog, too?
We used an Alaskan Yellow Cedar soundboard. Why? Mary thought the color value went well with the B&S. Yes, we used Honduran Mahogany for the inner laminate of the double sides.






Quote:
Originally Posted by printer2 View Post
Now you got me itching to see what would happen if you had a lightly braced outer back to go with an iner back. Probably easiest to take a finished guitar and add a 'gasket' and plate to it. Now if I was not working on a dozen projects already (and that is how I get to a dozen, the old 'what if'). Looking forward to seeing Mary take pictures of you holding a pose over the current beauty.
You might just be onto something there Fred but that's all I'll say about that subject









This isn't the Reecho guitar but this picture shows the identical bracing that I used on the Reecho's laminated back ... before ... the Reecho was added
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  #42  
Old 02-18-2020, 06:50 AM
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OK, I think I know where you're going. The bracing being "incomplete" was the clue. I think I saw you do this once before recently, didn't I?
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  #43  
Old 02-18-2020, 02:31 PM
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Hi Neil,
The bracing, which I pictured above, is complete. It uses 3 parallel ladders bars and the 4 individual disconnected or decoupled fan braces. The lower ladder bar is used to tune the back’s frequency by removing material from the center of the brace. This pattern is similar to what Australian luthier Trevor Gore uses.

Keep in mind that this is not the reecho guitar but rather a facsimile of the bracing I used on it’s back prior to adding my reecho device.
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  #44  
Old 02-19-2020, 05:16 AM
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The reecho will also feature our optional offset sound hole placement as well. Although offset sound holes are not as popular aesthetically I like the added benefit of moving the sound output much closer to the player's perspective.











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  #45  
Old 02-20-2020, 07:04 AM
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Well, here it is ... the reecho, which literally means to resonate, resound, reverberate or reflect sound. That was my end goal of this entire project. Since this set of Sassafras was so dead and high damping I wanted to find a way to reecho the voice of the top back to the player and audience.

Before I added the reecho disc and the guitar's top, I tapped on the back, as I always do and the tap tone was greatly improved just by adding an inner laminate of mahogany. The tap tone wasn't spectacular but certainly a notable improvement over the voice of the dead and lifeless tone of the Sassafras plate.

After I mounted the reecho disc but before the top was glued on I tapped on the outer back and I was astonished at the voice of the back assembly. It was much louder, responsive and it had considerably more sustain which was what I was hoping for.

The reecho disc is mounted in the center of the lower bout by a single carbon fiber post, which is glued to a spruce block which is in turn glued to the inner mahogany back laminate. The reecho is suspended midway between the back and top and is not touching anything else inside the sound box. When I tapped on the outer back, that energy was transmitted mechanically through the carbon fiber post to the center of the reecho disc, which set the disc in motion and made it vibrate. It almost acted as if it were a loud speaker transmitting the back's tapped input into a lively and very audible output of sustaining energy.

I chose to mount the reecho disc by a single point, similar to how a cymbal is mounted to a single point on a cymbal stand commonly used in a drum kit. The center of a disc is its node, or non vibration area, which allows the remainder of the disc to vibrate freely. When I tapped the outer back, I heard mostly the reecho disc resonantly vibrating. I still heard a little coupling of the back but mostly the reecho disc and now the frequency of the tap tone was slightly lower and bass biased due to the additional mass on the back.

I knew I was onto something special at that point but I didn't know how its voice would change after the top was joined. Things can change unexpectedly when you close up the sound box but I had to keep forging ahead. So, I glued the top on and bound the box.

Since the top and back can be vibrating 180* out of phase with each other, my fear was that the reecho disc might cancel out the top's input, or the back's coupling or possibly both. Now that the box was closed up, when I tapped on the back I was puzzled because its voice had changed. I tapped the top and the same result, it had changed too. The changes were not as I had feared but quite the opposite.

This is a VERY lively guitar but the sound of what I am hearing is like nothing I've ever heard before and I don't know how to describe in words what I am actually hearing. It has a quasi-stereo (if that's a word) kind of sound, like I hear a LOT more than what one would hear in a guitar with a side sound port. If you have played a guitar with two side sound ports, its more along that line but it still has more going on than that which is just plain describable.

The guitar is in finish now and it will be another three weeks before I have it strung up so you will have to follow along for the final results.











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