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Hi all!

"Built under Tension" - this phrase is often used to describe the Larson Brothers guitars (like the Wm. Stahl I am basing my new-builder challenge guitar on). Best I can tell, it was coined by George Gruhn and/or Bob Hartman, and it is not at all clear what exactly it means.

What is clear is that Larson Brothers instruments have unique, and perhaps fairly extreme arching to their plates, and I could use some advice on how to go about approaching this for my build. The prominent arching is one component that leads to the unique Larson sound, so I would like to attempt to recreate this.

The example published in American Lutherie (Winter 2012) describes the top has having a 12' radius and the back a 10' radius, but more cylindrical rather than spherical.

In an interview with Fretboard Journal (http://www.blogtalkradio.com/fretboard- ... talk-radio), Frankie Montuoro (who builds in the Larson style) used the example of shaping the braces to 20' and gluing them to the plate in a 15' dish. This could be one aspect of "building under tension."

Furthermore, some sources say the sides are dead straight along the top edge, and on the bottom, straight from tail waist, then a straight taper to the neck block. This would require forcing the top and back plates down to meet the sides at the waist, increasing curvature in a cylindrical manner (this may be one another aspect of "building under tension"). I've seen at least once source that said the sides were wider at the waist as would be done normally when building in a radius dish, though…

So, my dilemma is figuring out the best way to proceed. I have a 15' dish, so I am inclined to consider Montuoro's approach and using the straight side to increase the radius across the top. I can certainly make another dish (or something, or even use the 15' dish) to take the same approach with the back.

I am concerned about too much doming between neck and bridge, making setting the neck more challenging… For this, cylindrical arching would be better than spherical.

If you've read this far, and have any suggestions, I'd love to hear 'em. Anyone else ever do something similar to this?

Thanks!
Dan

Looks like I'm headed into uncharted territory! Kind of makes one wish they'd picked something simple, like yet another dreadnaught... (Not!)

Okay I am in no way and expert on Larson's guitars but I believe the term applies to their arching of the top and back plates. Now many builders use an arch on the top now and even the back. Back then most were building true flat tops. Today most flat tops actually have an arch. On the Larson's it is not only a side to side arch it also a front to back and it is very noticeable if you lay a straight edge on the top. It is more profound then some guitars today. The sides are shorter on a Larson's compared to most guitars but if you measure body thickness at the sound hole from top to back it equals the depth of standard similar styled guitars. I have only seen one of these in my life. A friend had one in his collection and he actually pointed out these details to me. Now i thought i remember someone on here building a Larson style guitar. Surprised no one else has commented....Mike

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