Compound radius costs.

[Rodger Knox]

For the strings to have the correct relationship with a curved fretboard, the saddle must also be curved, ie the inside strings are higher than the outside strings.
This affects the tone because the inside strings have a longer moment arm in the force that's rocking the bridge, so the inside strings are more effective in rocking the bridge. It's not as significant as it might sound, only about 1/7 of the ouutput from a guitar is from the bridge rocking.

[wuzzo]

Originally Posted by Rodger Knox

For the strings to have the correct relationship with a curved fretboard, the saddle must also be curved, ie the inside strings are higher than the outside strings.

Yes, I'd expect that for a good, even, action on the higher frets. The fretboard would be naturally flatter up there though, as the radius flattens with the fingerboard width ?

This affects the tone because the inside strings have a longer moment arm in the force that's rocking the bridge, so the inside strings are more effective in rocking the bridge. It's not as significant as it might sound, only about 1/7 of the ouutput from a guitar is from the bridge rocking.

Thanks for that.

[Bruce Sexauer]

The saddle height may or may not make a 1/7 difference in the tone. . . Those numbers don't play for me. . . But saddle height tonal difference is not subtle, especially to those of us who have dealt with these issues for a lifetime.

A Compound radius guitar fingerboard can be made so that the nut is very curved, the 20th fret is barely curved, and the saddle is dead flat, or even concave. If, for instance, the nut is 9" positive and the 12th fret is flat, the saddle will be 9" negative.

[Rodger Knox]

Originally Posted by Bruce Sexauer

The saddle height may or may not make a 1/7 difference in the tone. . . Those numbers don't play for me. . . But saddle height tonal difference is not subtle, especially to those of us who have dealt with these issues for a lifetime.

A Compound radius guitar fingerboard can be made so that the nut is very curved, the 20th fret is barely curved, and the saddle is dead flat, or even concave. If, for instance, the nut is 9" positive and the 12th fret is flat, the saddle will be 9" negative.

No, not a 1/7 difference in tone, a 1/7 contribution to output. The differences would be much smaller.
Are you saying that the differences due to the curvature of the saddle are significant?

[Bruce Sexauer]

Originally Posted by Rodger Knox

Are you saying that the differences due to the curvature of the saddle are significant?

They certainly should be, Rodger. I have definite preconceptions about what a sixteenth of an inch of saddle height does to tone, not to mention volume, that is the ball park of the height difference in a 16" radius saddle. Most Guitars use a more or less symmetrically radiused fingerboard, and then because action must be higher on the bass side than the treble side the saddle is a sixteenth higher on the bass side than on the treble side. Because the center of a 16" radius saddle is about a sixteenth higher than the ends, this means the center to bass side is about the same height, whereas the treble side is lower. This has tonal and volume implications which almost all guitar players are struggling with, whether they know it or not. For the last twenty years or so, my guitars have a slight twist in the fingerboard which causes the two ends of the saddle to be much closer to identical heights. If you think I am exaggerating, have a look at one of my guitars next chance you get, or check out my site, where some photos do show it. I consider balance to be the true frontier of the acoustic guitar, and this is one of areas that has received too little attention. I consider the feature I am talking about to be vastly more of an issue than variable radius fingerboards, though the two concepts are not mutually exclusive.

[CoolerKing]

Originally Posted by wuzzo

Reading this article makes me think that non-compound radius necks are actually inferior;
http://www.warmoth.com/Guitar/Necks/Radius.aspx

Are they very difficult to produce and how much more expensive should they be ? Twice the price ? Less ? More ?

Hopefully that image is exaggerated otherwise that looks like wrapping your hand around mr potato head --too fat at the bottom and too narrow at the neck.

[wuzzo]

Originally Posted by matthewpartrick

Hopefully that image is exaggerated otherwise that looks like wrapping your hand around mr potato head --too fat at the bottom and too narrow at the neck.

Yes, I'm sure it's just for illustrative purposes for those disadvantaged people unable to visualise the difference between 10" and 16" radii at will.


I've lost interest in the concept for the time being. I'm getting wrapped in the specs. for my forthcoming acoustic jumbo acquisition.

[wuzzo]

Originally Posted by Ken Franklin

Check out Lame Horse Guitars. That's what Chris and Jeremy do and Todd Hallawell is a fan. http://www.cjenkinsluthier.com/cjenk...ents_Home.html

Thanks for that, Ken.

[BrunoBlack]

I’ve resurrected this 4-year old thread in response to a current discussion about guitar necks that started to drift toward a sub-discussion about non-compensated vs compensated fingerboards. Not all guitar makers are clear how they make their fingerboards. Some like Collings indicate they have a 14-26 inch compound radius. Others simply say they have a 12”, 14” or 16” radius. Since some builders seem to make single radius fretboards: how do they accomplish this as the spacing of strings & width of freatboard spread toward the bridge. And is there any advantage to having a non-compound radius. Sorry if I missed this explanation in one of the links. StewMac provides some nice visuals describing a compound radius on this link.

[jim1960]

Originally Posted by wuzzo

Are they very difficult to produce and how much more expensive should they be ? Twice the price ? Less ? More ?

My new Circle Strings 00 is being built with a compound neck. There was no upcharge for it. Click here for the build thread.

Adam Buchwald at Circle Strings makes really great instruments and his base price is very reasonable.

[LouieAtienza]

Originally Posted by Haasome

I’ve resurrected this 4-year old thread in response to a current discussion about guitar necks that started to drift toward a sub-discussion about non-compensated vs compensated fingerboards. Not all guitar makers are clear how they make their fingerboards. Some like Collings indicate they have a 14-26 inch compound radius. Others simply say they have a 12”, 14” or 16” radius. Since some builders seem to make single radius fretboards: how do they accomplish this as the spacing of strings & width of freatboard spread toward the bridge. And is there any advantage to having a non-compound radius. Sorry if I missed this explanation in one of the links. StewMac provides some nice visuals describing a compound radius on this link.

The StewMac link is misguided, because very, very few builders produce a fretboard that'sa true conical section, that is one where the tip of the cone coincides with the convergent point of the lines tracing the two outer strings.

I also showd in the old thread Murray referenced that the "bulge" resulting from doing a pure cylindrical section, under the outside atring, for a typical string spread, at around .001". .0008" to be exact.

In essence, the builder would "true" the fretboard surface under the string paths and blend those "facets", creating a "ruled surface.". A conical section is a special case scenario.

[BrunoBlack]

Originally Posted by LouieAtienza

The StewMac link is misguided, because very, very few builders produce a fretboard that'sa true conical section, that is one where the tip of the cone coincides with the convergent point of the lines tracing the two outer strings.

I also showd in the old thread Murray referenced that the "bulge" resulting from doing a pure cylindrical section, under the outside atring, for a typical string spread, at around .001". .0008" to be exact.

In essence, the bulder would "true" the fretboard surface under the string paths and blend those "facets", creating a "ruled surface.". A conical section is a special case scenario.

Interesting, thanks. I asked Michael Millard how he approached his builds. He has a constant 20” radius. He said his fretboard is a section of a cylinder.

[LouieAtienza]

Originally Posted by Haasome

Interesting, thanks. I asked Michael Millard how he approached his builds. He has a constant 20” radius. He said his fretboard is a section of a cylinder.

Bausin in the build and repair section confirmed my results. The larger the radius, the smaller the "error" or hump. I did find some of the notes I took on this many moons ago, and recreated my spreadsheet that shows the difference from straight for each fret. I will add tonight "compound" radius and heights and differences for the second string as well

[mercy]

One of my guitars has a compound radius 16-22" but I dont bend and certainly would not up that high so for me the compound radius is unnecessary. I think it is an electric guitar thing.

[LouieAtienza]

Originally Posted by mercy

One of my guitars has a compound radius 16-22" but I dont bend and certainly would not up that high so for me the compound radius is unnecessary. I think it is an electric guitar thing.

Yes, if you don't bend and don't want an unnecessarily flat board higher up, then it is not needed. It is, however a by-product of hand shaping and truing a fretboard of constant thickness and edge height.