However, I can't find any information regarding the effects or practicality of a radius less than 25 feet. Does anyone here know if there is a definitive radius at which the severity of that radius reaches a point where the tone would not be considered favourable to anyone?

Hans Bentrup, who used to share here on this forum built with 10 or 15 ft radius(I don’t remember which).

Hans Bentrup, who used to share here on this forum built with 10 or 15 ft radius(I don’t remember which).

If you get much smaller than 25’, you will have trouble with neck/fingerboard alignment to the bridge. 25’ to 28’ puts your neck angle with a straight fingerboard right where it needs to be to get a 1/2” string height over the soundboard at the bridge. With more curve than that, you will have to taper the fingerboard or go with much higher strings at the bridge. Of course, you could use a cylinder rather than a dome. As you decrease the radius, the top will get stiffer (all other things being equal) and you will probably lose some bass.

Google "Howe Orme guitars" which btw our friend Rick Turner collects and see guitars with a MUCH tighter radius than any you are describing.

I would add that the impact on tone of the radius that you found somewhere on the Internet is BS.... "Brightness" is a function of many things, materials, bracing patterns, top thickness, back materials and even strings and more...

Before doing any experimenting I would also ask if this is the first guitar that you have built? If so I would study convention and get the wood working, neck angles, lots of new stuff down before I attempt to reinvent the wheel. Just a suggestion, welcome to the forum.

Fred, I think the advice above relating to reinventing wheels is truth itself. Besides which, without a baseline it's going to be impossible to tell if a modified technique does what is hoped for if it can't be compared to anything. So you're going to need something you made to a known pattern to compare a subsequent modified one against. It's an awful lot of work to build a guitar. I think you're well served building the first one with commonly-accepted parameters and innovating in the future. Is that a lot of work? Yup.

First off, experimentation is laudable.

However I agree with Hesh that a guitar is a complex system and you cannot just boil things down to “more top radius equals more brightness”.

If your main goal is more “brightness”, there are many paths you can go down and many easier variables to experiment with in the realm of bracing design, materials etc that don’t involve fundamentally altering the string geometry of the instrument.