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  #31  
Old 01-07-2019, 04:22 PM
Tom2 Tom2 is offline
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Quote:
Originally Posted by mountainmaster View Post
16" radius.
Thanks.

If we think of a flat fretboard is a radiused fretboard with infinite radius, 100% of the finger force is orthogonal to the fret, preventing sideways slippage. As the radius gets smaller, a higher percentage of finger force is tangential to the fret, facilitating sideways slippage.

While this is not a big deal for steel strings, due to high string tension, it's clearly a design issue with lower tension nylon strings.

I think a 20" radius will reveal itself to be optimal for nylon crossovers.
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  #32  
Old 01-07-2019, 06:48 PM
EvanB EvanB is offline
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Tom2;

Well, that's interesting. While most of the contemporary nylon string CF guitars come with high-tension strings, I prefer low tension. I'd never thought of going beyond 16 and now you have me thinking of 20.
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  #33  
Old 01-07-2019, 07:12 PM
btbliatout btbliatout is offline
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For the sake of fun and jest, an inverted fret board would minimize required finger curvature, allowing more force to go straighter into the hand :-). If only we could live without barring...
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  #34  
Old 01-07-2019, 07:38 PM
Tom2 Tom2 is offline
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Originally Posted by EvanB View Post
I'd never thought of going beyond 16 and now you have me thinking of 20.
It's what I do.

BTW, the Rainsong is 20". If it had a wider nut, that beautiful marine burst would be at my place instead of yours.
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  #35  
Old 01-08-2019, 10:37 AM
EvanB EvanB is offline
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Tom;

Well, that explains my adaptation to the RS parlor. I was skeptical about the 1 6/8" nut width but got used to it and found the neck and fret radius to be highly satisfactory. And the beautiful marine burst is very fetching.

If I have another Emerald ultra-thin electric nylon string guitar made I am thinking a 10-build, short scale, 20" radius, 1 7/8" nut width and a Barbera pickup. The 7 ultra-thin short scale turned out to have remarkable projection and is a marvelous electric/acoustic instrument--something quite different from an acoustic/electric.
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  #36  
Old 01-08-2019, 12:27 PM
mountainmaster mountainmaster is offline
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I actually wanted a 48.5mm nut but I was fooled by the specifications for the X20 Nylon Artisan on Emerald's website. It says: Nut Width 1 7/8", 48.5mm. Being a metric guy I focused on the latter but copied both in my specs to Kevin.
Unfortunately 1 7/8" is closer to 47.6mm and that's what I got. Now 0.9mm extra may not seem that much but it could probably have eased the high E-string slippage.

Apart from slippage this nut width also poses a higher risk of accidentally muting an open 1st string if one does not position the left hand in the classical way. IMO a crossover nylon guitar should allow for both classical and steel string hand positions.
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Emerald X7 Nylon
Rainsong Smokey SMH
Taylor 522e 12-fret
Gitane DG-560 nylon
Alhambra 3C CW
Eastman AR910CE
Recording King RK-G25 6-string banjo
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Last edited by mountainmaster; 01-08-2019 at 12:33 PM.
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  #37  
Old 01-08-2019, 01:27 PM
Tom2 Tom2 is offline
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I'm a lead electric guy who uses a pick, even with nylon. No classical technique at all. Using D'Addario EJ44 extra hard nylon strings on a guitar with a 16" radius, I need 4.5mm between the first string and the fretboard edge at the nut in order to play freely without the need to think about anything. Combined with my preferred string spacing of 41.5mm at the nut, a 47.6mm nut width leaves 1.6mm between the sixth string and the fretboard edge.

I actually made one of these nuts, and am using it right now. Can't play the sixth string at all, so I'm using the guitar like a sitar in drop D tuning, using the wound strings as drones and playing only the clear nylon ones. Everything is a modal improvisation in D.

A 49mm nut with offset strings would increase the sixth string gap to 3mm. A 20" radius would allow me to reduce the first string gap to 4mm, increasing the sixth string gap to 3.5mm. This would be quite usable for both classical and steel technique.

I worked all of this stuff out with custom nuts and saddles about a year ago, including string height and neck width at the 12th fret, shared my findings on this forum, and interacted directly with people from Rainsong, Journey, and Emerald, but not Blackbird. I was surprised that no manufacturer wanted to use me as a design consultant, especially since I was willing to do it for free and pay for the first prototype, and I'm an engineer.

Now I'm composing and recording, which means doing the best I can with what I have. I may resume this crossover design project when I'm done recording. Cedar/mahogany/nylon ragas actually sound quite good in this moment.
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  #38  
Old 01-08-2019, 04:31 PM
EvanB EvanB is offline
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Tom2;



I've been using you as a design consultant and while I don't always follow your advice I try to closely listen.

If you are willing to pay for the prototype of your dreams why don't you commission Emerald for the build? I've done a lot of fumbling around in my search for my ideal nylon string guitar, but I haven't started with your knowledge and I've also been dealing with a changing aging body and changing taste. Given the exactness of your calculations I think you would get to your ideal guitar at a much quicker pace than mine.
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  #39  
Old 01-08-2019, 11:17 PM
Tom2 Tom2 is offline
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I realized that I want a guitar built from scratch as a crossover, not a modified steel string design. This would require an Alistair Hay Custom Design instead of a custom X10N. I'm guessing this is significantly more expensive, so no rush.

Basically I want to start with the exact dimensions of the finest classical guitars, with only ergonomic modifications to accommodate steel string technique, such as a cutaway, narrower neck, slightly radiused fretboard, and lower action. I also want a centered soundhole because I record with a spaced pair of small diaphram omni condenser mic's, and the offset soundhole would throw off the stereo imaging of the recording.

I think that, when dialed in, this would make a nice production model crossover that would take the guesswork out of making a custom order for people who haven't done the kind of experimenting that I have.

We'll see.
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