Official Luthiers Forum!

Discovered today that Kevin Ryan builds all his guitars with a 7 foot back radius. Has anyone tried this? Just looking for a general discussion of pros and cons versus the typical radius of 15 foot or thereabouts.

I asked luthier bill moll in sgfld MO/ why he uses it, because of the wide fluctuations in humidity he puts that 7 ft radius on his backs to countereffect the high humidity in summer 60 + and less than 30 in winter , seems to do the trick in places where there is signifigant humidity changes . Have not tried it so far, but he did suggest it to me , because of the warping I get from some backs esp . local !/4 sawn sycamore.

Before you get enamored with Kevin's back, keep in mind it makes binding the back VERY hard, particularly on venetian cutaways.

At this point I'm merely curious and particularly the difficulties that arise from using a tight radius back, so I'm glad to see comment regarding the increased difficulty in binding.

One of the biggest obstacles to overcome will be people always saying you copied Kevin's design.

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http://www.CostaGuitars.com
PMoMC

^^tony, wise words

I presently use 15 ft. radius dish for both back and soundboard. I have been toying with the idea of an 8.5 ft. dish for mandolas.
Anybody tried anything in this direction.

Bob

My question was a technical one and nothing more. I do not want to switch the conversation to one of ethics since the luthier world is full of copying. Only one person created x-bracing but the percentage of steel strings built with one is likely in the high 90s. Innovations such as armrests, side ports and wedge guitars are part of many guitars built by people on this forum but do the builders reference Grit Laskin or Linda Manzer? Some do, some don't.

Just looking for pros and cons of a tighter radius on the back. If people have constructive input I welcome it.

Thanks for the comment Filippo. You have me curious about Manzer. She has info on her site saying she created it and how makers should reference her so that is where my comment came from. Some innovations have been around for 200 years and then someone "claims" it. I have no evidence but I heard that fan frets fall into that area. if you have info about pre-Manzer wedge guitars please share.

Linda never demanded that anyone put a label on their guitar or website, rather she merely asked for an acknowledgement.

By acknowledging other's contributions we make our own original work have more gravitas. Most of what we all build is borrowed. A handful of innovations are either completely new or refinements on historical work. Are you who are resistant to a simple acknowledgement so insecure in your own work that you cannot bring yourself to such a simple doff of the cap?

Linda came by her work honestly. She was a lone woman in a man's world of luthierie, with no internet. There was no consensus on procedures or repair as there is today. There wasn't much of a library either -- the only texts were those written by Sloane, Young, Don Teeter, and despite their contributions, there was a paucity of information. She was a part of a group of young builders who together forged a new era in North American luthierie. She's earned everything she's worked for. All of you who sit behind your computers and act with such authority with less than a pinky of her experience or contributions to the guitar community and take designs from anyone you care without so much as a "hey, I like what you've done, do you mind...." have no business coming down on Linda.

All that AND she is super cool to boot!

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Lance@LuthiersForum.com

Note: I have never not seen Linda smiling.

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Support the OLF! Bookmark our STEWMAC link Today!
Lance@LuthiersForum.com

The stiffer(less flex & a high resonance) the back-the less it takes from the top.
Make a supple top & stiff back & sides.

Mike

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Mike Collins

That's one view. Another is that the back contributes complexity and by reducing the back's influence, the overall tone becomes less complex. Rather than taking from the top, the back contributes. Lessen it's influence and the top stands more alone.

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Old growth, shmold growth!

I keep my computer open on the workbench 'cuz I communicate a lot with customers on Facebook.
Makes it easy to slap down a comment here and there between jobs and whatnot.

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Old growth, shmold growth!

pthes .. fan frets in the 1600s ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I just find a stiffer B & S help with the tone,volume & projection
My clients need.
A loose(flexible) back is hard to control.
And can really mess up a clear,clean sound.
Mike

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Mike Collins

My comment was meant to be a joke, but I guess it could be taken seriously.
I have innovated exactly zero point zero things with my guitars. Everything I do has been done before. Including my mistakes.


Sent from my iPhone using Tapatalk 2

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http://www.CostaGuitars.com
PMoMC

Well, as ever, it's not a case of just one type or the other. Both live and non-live backs have their very valid places. As I've said before, (and very simplistically) stiff backs give "volume" and live backs give "tone". Floppy backs (as Mike has suggested) kill both. It's a case of knowing what the alternatives offer and when to use them.

For guitars played acoustically I generally use a live back with a 3m radius dome (that's about 10 feet). Not seven, but I wouldn't want to bind a back with a Venetian cutaway with a seven foot radius. 3m radius makes it difficult enough. The majority of my SS guitars have Venetian cuts.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I'm not sure I said "loose floppy back".

I just said the back's influence makes the tone more complex, and lessening it's influence makes the top's influence dominant.

The back doesn't have to be loose and floppy to contribute.

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Old growth, shmold growth!

Having checked back, I'm sure you didn't!

I was just making the point. Both live and non-live backs work fine, which means giving them the right degree of stiffness for the job. I've seen/heard a few floppy backed guitars and acoustically they don't seem to do anything well.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

OK, here's some more technical terminology:

Live backs produce a T(1,1)3 resonance.

Non-live backs don't produce a T(1,1)3 resonance.

Floppy/loose backs have a T(1,1)3 < T(1,1)2 (which is not strictly correct use of the nomenclature, but those who know will understand )

Is that better?

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

" D T's" - delirium tremens - a.k.a. "shaking frenzy" ?

Not really. Filippo

I'll say!!

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jw ( o)===:::

What he's saying is that a live (not floppy) back contributes frequencies making the tone character more complex. A floppy back will contribute wolf tones and tuning dissonances.

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Old growth, shmold growth!