wingless bridge, 7 strut interlocking hyperbolic bracing

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soundshooter
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wingless bridge, 7 strut interlocking hyperbolic bracing

Post by soundshooter » Sun Jan 08, 2017 10:03 am

Hello Friends
Thought you might find something of interest or maybe provocative with my last build.

Named White Tara
Completed 6/16
Hours 200
Designer Frank Truncale
Type Nylon classical
Fret @ ub 12
Bracing 7 strut interlocking hyperbolic radial
Top wood Sinker Cedar
Back & sides cocobolo
Neck Honduran mahogany
Neck radius 20
Binding cocobolo
Bridge Brazilian Rosewood
Compensation nut and saddle
Nut width 53mm
Saddle 58
Scale length 650
Headstock open straight pull FET
Mass loaded 400g
Back live
Neck design BOBO
Pick up none
Ornaments Seven Eye rosette
Finish Shellac
Sound port yes

I was inspired by the work of Jurgen Meyer to make a guitar using a wingless bridge. To keep a functional gluing surface to the top I essentially condensed the typical area into a soft heptagram that is supported by an interlocking radial bracing design. The bracing was inspired by the work of Greg Smallman (lattice bracing), and Trevor Gore (falcate bracing) and the desire to incorporate an element of sacred geometry (Steve Connor).
White Tara.jpg
Tara rossett.jpg
White Tara deity with seven eyes
Tara Headstock.jpg
Semi Strait pull
Tara Bridge copy.jpg
sound board 01.jpg
bracing arranged asymmetrically from bass to treble
sound board go bar.jpg
go bars this time vacuum to come
bridge 01.jpg
Bridge fabrication jig and drawings
0519161357a_HDR.jpg
Brazilian Rosewood, carbon fiber reinforced bridge in process.
sound board 04.jpg
curved and laminated LTB, carbon fiber applied.
Screen Shot 2017-01-07 at 2.51.05 PM.png
T(1,1)1 107.5 T(1,1)2 202 T(1,1)3 239
Attachments
IMAG4330.jpg
Bent and laminated indian rosewood linings, both sides. Kind of over kill

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kiwigeo
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by kiwigeo » Sun Jan 08, 2017 10:22 am

Well what can I say??? Some thinking way outside the square going on here. Nice work...
Martin

routout
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by routout » Sun Jan 08, 2017 10:29 am

I'm certain if you don't try something different then how will you know,the eyes have it . :D
John ,of way too many things to do.

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Mark McLean
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by Mark McLean » Mon Jan 09, 2017 9:30 pm

Hi Frank.
That looks stunning, and your execution looks very precise and clean.

How did you come up with the bracing concept? I can see the obvious influences of falcate and lattice bracing patterns. My first impression is that it might be more bracing than needed? It would seem to be a lot more bracewood than in a "standard" falcate pattern as per the G&G books - but that would depend also on the height of the bracing of course. Does it feel like a stiff top, or have you done any deflection testing? I guess the weight of the bridge is less that usual which will be another factor affecting the top performance.

Overall, a really interesting concept, and showing lots of advanced technique. Nice job
Mark

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lamanoditrento
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by lamanoditrento » Mon Jan 09, 2017 9:41 pm

Wow! Please don't take this the wrong way, but I am equally fascinated and disturbed. It is shockingly different.

Any comments on the sound would be fantastic?

How did you manage the straight string pull with 3 on a plate turners? Is it a slight inverted angle of the headstock sides and re-drilled sting holes?

Congrats!
Trent

Dave M
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by Dave M » Tue Jan 10, 2017 9:55 am

Well Blimey! First of all it looks like great woodworking skills. But please talk about the sound. And how high are those braces?

And go on give us a sound sample!
------------------
Dave

Jim
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by Jim » Thu Jan 12, 2017 12:30 pm

Wow stunning work! I too am very interested in your opinion of the sound. Which innovations did you think were most successful?

soundshooter
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by soundshooter » Thu Jan 12, 2017 5:18 pm

Thank you for you interest, comments and questions. I’m not sure how to answer the question of how I came up with the concept but will give it a try.

I am attracted to the strength and density of lattice bracing, yet there seems to be a signature sound that is sort of grainy or mechanical. I hypothesized that perhaps it was because of the squares that are made. It is my notion that the underlying mechanics of a square and the way in which it controls the top is what is responsible for the sound we associate with a lattice. What became most fascinating to me about lattice bracing was actually the interlocking bracing.

Lutherie is the study of nature. We study the nature of material, the nature of sound and the nature of perception. Anyone who has studied the concept of the golden mean understands nature does not willingly divide into fours. Music itself is based on thirds, fifths, sevenths and ninths. Most of our hero luthiers use these concepts in their designs. I am drawn to an aesthetic that inherently employs some of the chaos of nature rather than trying to control it with a box.

Falcate bracing inspired my imagination. Does a strait line in nature really exist? Light even bends around objects. On a guitar, the one thing that could be truly thought of as straight is the stretched string, yet it is the oscillating string that powers the instrument. The defiance of the straight line could arguably be the basis of the whole concept of a guitar. These musings make the notion of curving braces seem quite attractive on an artistic, metaphysical level.

As a luthier I strive to create powerfully inspirational tools for creation. However serious that might seem, guitars are also about play. I think that being playful with the design can serve the evolution of the instrument. Being playful does not come without risks. The White Tara was a 200 hr, $700 experiment. The sound of the guitar is quite lovely. The tone is rich and lush, with the definition and clarity that you might expect from falcate bracing. It also has an even tone with plenty of sustain. I’ve included a sound sample, so I’m interested in your perceptions. My playing, ugh, please overlook my stumbling about.

https://soundcloud.com/frank-e-t/whitetara-guitar-demo

I do think I underestimated the strength of my bracing (Sitka 5mm wide about 5.7mm high in center). Looking at the modes you can see they are fairly high, even with the use of lots of mass in the sides. The bridge weighs in at 15 grams. Top thickness is to G&G book for classical (60), about 2.2mm . Bridge rotation is maybe 1.5 degrees. The amount of bracing (not talking height) really isn’t that much more than a 7 strut fan, certainly less than the Fleta. Even though the guitar has been described as lively, no one would say it is a loud guitar.

I’m currently working on a steel string with 5 interlocking braces and the wingless bridge. Please, any ideas, observations and comments that would help with my next build would great.

Frank
Tara End graft.jpg
End Graft
Tara back sound port.jpg
oil finshed neck

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kiwigeo
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by kiwigeo » Thu Jan 12, 2017 6:33 pm

Frank, what was the process you went through to arrive at nut and saddle compensation?
Martin

soundshooter
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by soundshooter » Fri Jan 13, 2017 3:59 am

Hi Martin.
The compensation was set up for gsp ultra hybrid strings(seen in the photo). They are branded by a local SanFransisco institution, Guitar Solo. They are most like Hanambach titanium strings at about a guarter of the price. I started with the set up for classical guitar in the G&G book and worked empiricaly from there with as least four iterations over the course of two guitars. I spent days trying to build a spread sheet but between the maths and the programming I was, for the time being, defeated. I also built a test rig for 24.5 scale which helped immensely to get my brain around what was going on. One more note, the sample recording was made with some plastic wound strings that need a totally different setup. Maybe you heard that?

soundshooter
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Joined: Sat Aug 11, 2012 4:39 am
Location: Oakland USA
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Re: wingless bridge, 7 strut interlocking hyperbolic bracing

Post by soundshooter » Sun Jan 15, 2017 6:13 am

Hi Jim
I see the bridge and bracing as a system, a single innovation. No point in using the bracing with a traditional bridge. The wingless bridge on x bracing or traditional fan doesn't seem practical. It succeeds in being a good first try. I think it's true character will expose it self as I start building lighter. I have some suspicions about what is going on and how it works, but need to do some chladni testing to get a more realistic view.

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