Concerning Larson Bros Radiusing.......

[Sam VanLaningham]

Hello builders, repairers and luthiers!

I'm fascinated conceptually with top and back radiusing. I've read quite a lot of threads about it and find it even more interesting. I love the concept of thin, light, strong, curved (I knew there was a correlation with my preferred guitar style and female style and now I just Freudian proved it..... I guess). I've not played any of these but only heard recordings of tight radiused vintage guitars. I like the brightness and projection a lot. I love the aesthetic as well.

Anyways, I see that the Larson bros used some pretty tight radii for tops and backs, on the order of 12' and 10' respectively. Although I read that Ryan builds with a seriously radiused back, his tops are flattish. Somogyi likes 30' ish; gibson is usually 25' but it seems the consensus (whatever that means in guitars) leans toward gentle to no radius in tops. And that's fine! But I want some curve......

Thus my point: I'm thinking of going with a 15' top and a 10' back in a new L00 style build with radius accommodations made longitudinally for neck angle, back taper etc.

My query: what thinking/tonal-structural rationale went into the Larson bros deciding 12 and 10', or for that matter what went into gibson choosing 25' and 15' or whatever?

It's sort of a vague question but I'm open to any and all discussion on this topic. Thanks! Sam

[Sam VanLaningham]

Hi all-I'm guessing there's not much discussion here because not a lot of knowledge about the Larson bros?

Any more generic thoughts and especially experience and or 2nd hand stories about tonal results from using smaller radii for the top/back? Build comparisons of same body and woods but different radii?

So obviously a tighter radius increases strength and the resonant frequency of a top or back, and apparently leads to a brighter tone. It is also suggested thst sustain is reduced as well. I'm wondering what happens when you offset a tight radius top with a thinner top and/or a bracing layout that enhances bass WITH the tighter radius and resulting brighter tone? Or would these things fight each other more than work together?

Ok cool. Sam

[Glen DeRusha]

Usually if I have questions like that, what I do is physically drag myself out of the arm chair, go out to the shop, put the saw to the wood, and see what happens.

I would look at the guitars that I have been building, with the radiuses that I have been using, and see how they are working. Then I would build one with a tighter radius back, one with a tighter radius top, and one with a tighter radius back and top, and see what happens.

You do not have to use expensive, exotic, woods for the experiment. Flat sawn walnut for the back and sides should be fine. You don't have to put in a rosette or use binding for experimenting. That should save you some time.

Are you going to build off of a solara board? Radius dish and an outside mold? What kind of radius dish? One that is shaped like a section of a sphere? Or one that is shaped like a section of a piece of pipe?

If somebody else built one with tighter radiuses and said it sucked, I probably would not believe them. I would have to put one together myself and see what happens when I do it. The radius, or radii, that you use is just one pidgeon hole to look into. There are easily 800 other things that you can do, or not do, along the way, to change the voice of a guitar.

Hope that helps.

Glen

[printer2]

I think there are only a handful of heavyweights that advise us less experienced types who could answer your question. Sometimes it does take them a while to getting around to answering our questions, they have their own stuff to take care of. I have no good answer to your question as I am still asking my own. I was planing on making a test guitar to try out different ideas but for now just trying to finish a couple of projects.

On a related bent I am re-topping a plywood guitar which had no radius for the top or back. I am thinking of putting a mild radius to the top just to tell the wood which direction to expand when it gets in a more humid conditions (currently about 15% RH). Do not want to change the neck angle so the bridge can't change much from its original position. Just want to see what a top change would do to the sound retaining the back and sides. So kind of in line with Glen's advice of just go out and try it to find your answer.

[Glen DeRusha]

Not to far off topic but, Howe Orme did some interesting things with top radius.

http://www.vintageinstruments.com/mu...trfulpage.html

https://en.wikipedia.org/wiki/Howe-Orme

I would do something like that, just because it looks different.

Glen

[RRuskin]

Originally Posted by Left of Sam

Hi all-I'm guessing there's not much discussion here because not a lot of knowledge about the Larson bros?

Any more generic thoughts and especially experience and or 2nd hand stories about tonal results from using smaller radii for the top/back? Build comparisons of same body and woods but different radii?

So obviously a tighter radius increases strength and the resonant frequency of a top or back, and apparently leads to a brighter tone. It is also suggested thst sustain is reduced as well. I'm wondering what happens when you offset a tight radius top with a thinner top and/or a bracing layout that enhances bass WITH the tighter radius and resulting brighter tone? Or would these things fight each other more than work together?

Ok cool. Sam

I own a Stahl Style 6 and sustain is one of it's strongest points.

[Sam VanLaningham]

Thanks for the thoughts glen and printer.

I basically agree about just getting in there and doing it, with the caveat that at the same time I'm experimenting with tonal aspects I need to continue to improve my craftsmanship and aestetics skills. So I don't want just start making guitars out of just anything.....mostly I know myself too well that once I compromise somewhere, I am liable to get very loose. I figure if I do that with a guitar then I won't be giving myself a fair view of the tonal potential of the build.

But I will say that I mostly want thougjts and feedback on the topic as it stimulates me during the build! As I saw in my first guitar (curing-can't wait to buff and string up!) if Ive got my mind set on an idea, it's probably gonna stay there. So, I doubt anybody would sway me from building with 15' and 10' radii, but I like to fantasize about the tonal possibilities whilst cruising along.

I love the orme guitar, especially the wave top. Thanks for sharing that.

Printer, I just read about your diy torrefaction setup.....totally cool. Very experimental! I was wondering if it was possible in-house, though I'm not overly passionate to do it. I just love that you went for it!

[printer2]

Originally Posted by Left of Sam

Printer, I just read about your diy torrefaction setup.....totally cool. Very experimental! I was wondering if it was possible in-house, though I'm not overly passionate to do it. I just love that you went for it!

Did some more reading on torrifaction. Seems the darkening of the wood is due to the hemicellulose being cooked off and not because of my original thought of too much oxygen in my attempt. Been asked about my test at another forum so I did some further reading. I am not pursuing cooking tops too seriously, I think there is enough aspects of my builds that can increase the tone content without jumping on the torrify bandwagon.

[capohk]

Have a look at NK Forster's take on the Howe Orme idea.

I'd love to have a go at this, I think I'd want a dedicated hollow form to shape my braces and clamp into my top.

I have Nigel's book - some lovely photography in and quite inspiring. He also uses a laminated brace of spruce and rosewood for extra stiffness.

Cheers

Matt

[Trevor Gore]

Stefan Sobell and Nigel Forster (who used to work with Stefan) both make guitars with "cylinder" rather than domed tops. The cylinder is quite a tight radius and their guitars have the Howe-Orme look. These guitars have a different sound and feel, which you either like or you don't, but some good music has been played on them if you listen to those who have them.

As you go to tighter domed radii you run into problems with the neck set angle matching the upper bout angle if you want the guitar to appear fairly traditional. That drives you toward either a tilt neck or an elevated neck to get around that. With the cylinder top, the neck set is less of an issue. There's a chart in the book (not Nigel's book, the above post came in as I was typing!) which compares the rise in natural frequency of a panel due to increasing amounts of spherical curvature with the natural frequency of a flat panel with the same boundary conditions (p 1-78).

[Sam VanLaningham]

Originally Posted by capohk

Have a look at NK Forster's take on the Howe Orme idea.

I'd love to have a go at this, I think I'd want a dedicated hollow form to shape my braces and clamp into my top.

I have Nigel's book - some lovely photography in and quite inspiring. He also uses a laminated brace of spruce and rosewood for extra stiffness.

Cheers

Matt

Yeah a combined Larson-orme approach. Very cool! Like what I'm seeing conceptually.

I did notice on forster's website, he says

"The “standard” soundboard is considerably more curved than a conventional steel string guitar and the ribs are fitted to meet the back and top perfectly – the plates are not “pulled” to meet the ribs as is common"

This sounds sort of like he's NOT using a radius dish type approach for creating the radius when glueing braces to the top. But I don't understand how else it would be achieved other than carving a curved top out of a block of wood????

[Sam VanLaningham]

Originally Posted by RRuskin

I own a Stahl Style 6 and sustain is one of it's strongest points.

That's what I hear when I've listened to soundcllips but it's not what somogyi and others say occurs from a tight radiused top, if I'm interpreting their words correctly? Anyways, cool guitars. I see you love yours as there's lots of pics out there on the Internet of you and a stahl! Cool.

[Sam VanLaningham]

Originally Posted by Trevor Gore

Stefan Sobell and Nigel Forster (who used to work with Stefan) both make guitars with "cylinder" rather than domed tops. The cylinder is quite a tight radius and their guitars have the Howe-Orme look. These guitars have a different sound and feel, which you either like or you don't, but some good music has been played on them if you listen to those who have them.

As you go to tighter domed radii you run into problems with the neck set angle matching the upper bout angle if you want the guitar to appear fairly traditional. That drives you toward either a tilt neck or an elevated neck to get around that. With the cylinder top, the neck set is less of an issue. There's a chart in the book (not Nigel's book, the above post came in as I was typing!) which compares the rise in natural frequency of a panel due to increasing amounts of spherical curvature with the natural frequency of a flat panel with the same boundary conditions (p 1-78).

I'm jonesing for this book you refer to. If I knew the author I'd ask for a trial copy.....

Haha!

Thanks for providing some thoughts. I Look fwd to seeing the frequency-radius data when I stop spending on tools and wood.

[geordie1]

For those interested in the Howe Orme design, here is my pal Seth playing my 100 year old Howe Orme.

This is a cylinder top, ladder braced adjustable neck guitar.




And here is a guitar I made based on the same design:




nigel

[Sam VanLaningham]

Originally Posted by geordie1

For those interested in the Howe Orme design, here is my pal Seth playing my 100 year old Howe Orme.

This is a cylinder top, ladder braced adjustable neck guitar.




And here is a guitar I made based on the same design:




nigel

I listened to these several times yesterday and was all over your site and then transitioned to sobell youtubes etc and was really moved by what you guys are doing! Thanks so much for posting. And I was thinking of posting same links because your orme could probably compete for "best guitar in the world?". After hearing yours I listened to a bunch of the 10k guitars at dream guitars as well as a variety of sobells, Ryan's, somogyis, sexauers, kim walkers, stahls and your orme really was more in my wheelhouse than some of those others (I really like walkers though). Smart move acquiring such an inspirational guitar. I bet it helped your building a ton?!?!?

Was your copy built before or after? Yours sounds really good as well but the combo of in your face mids+warmth is in your 100 yr old and must be a hard combo to build into a guitar.

Thanks again for posting. I feel lucky to be in an age where people who are inspirational to me randomly comment in a thread I started! Very cool.

Sam