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Many have commented their proclivity to make 12 frets because the bridge is moved toward bottom of guit. reating better sonic capabilities.

There must be downsides or, it seems to me everyone would build with 12 frets.

My suspecicions run to the shorter neck not allowing for more playability for those who frequently find themselves playing on the upper frets.
--12 fret with cut-out allows more room but the problems created with sound associated with shorter string length come into play.--Am I correct?- other reasons?
Is the 13 fret model an attempt to compromise this issue?
Thanks,

Yeah Bob buddy I think that you nailed it.

A 12 fretter places the bridge more in the center of the sweet spot of the lower bout of the guitar top and this helps with better response from the available input vibrations.

And - for upper neck players 12 frets are more limiting in terms of access to the upper frets.

I would, if you don't mind, want to know if a 12 fret is more resistant to needing neck resets, all things being equal (build quality, materials, etc.) since the neck is shorter.

Bob,

String length is independent of whether it's a 12, 13 or 14 fret. As grumpy says, base everything off the fret that's over the neck/body joint.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Classical have cont 12 a fret.other than tradition, must be something to it. Never have built one or asked to build one. when get setup again,I do plan on building one for personal use.

Talking to several pro players, all of who are touring with cma artist, or have own shows, (all full time players), they like the longer scale with a as they describe as a big and full sound. This doesn't matter the body type (OM, dred or whatever) They like the ability to go up (or down if look at it that way)neck. That is reason the cutaway from thier view anyway, has become a norm (whatever that is) again this is the prespective of only about 12 folks, full time players.

I like the sound of 12 fret. To me anyway, the tone is deeper and richer. I just notice a difference as say when play at the soundhole, not as full, rich (whatever one likes to describe as sound they like). I note the sound to me is more as described above, when play pick toward the nut.

Good question, Hesh! Since 12 fretters are my mainstay, this interests me as well. The repair experts should be able to answer this based on their practical experience over the years.

For a given scale length, I would imagine that the string pull force is identical and independent of neck length. What effect, however does the positioning of the bridge have in reacting to those forces? Seems to me that since the bridge is farther south and positioned in an area that we think vibrates more freely, it could also be less resistant to the torquing effects of string pull as well. So...I would imagine that 12 fretters might need a neck reset sooner. That's my hypothetical opinion and as always could be wrong.

I eagerly await the correct answer as well!

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JJ
Napa, CA
http://www.DonohueGuitars.com

JJ .. Dave Wren of the 12th Fret here in TO thinks the same thing - 12 fretters tend to belly more than 14s, as the bridge is now in a larger area, and the string pull can exert its force more easily - plus, if you are using a pyramid or simple rectangular bridge vs a belly back br design, the torque on the rear edge of the bridge is again increased

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Not all 12 fretters moves the bridge further back. Many simply make the body longer, moving the upper bout two frets.

Stan, Stan, please type more slowly!

The "sweet spot": I'm not sure what that means. I suspect it's part of the persistent mistake of seeing the top of the guitar as the cone of a loudspeaker (one of Kasha's big mistakes). "Sweet" meaning generating the most volume? sustain? total vibration transfer to the air? for which frequency or frequencies? At any rate, given the angle at which the strings pull and the torquing of the bridge, there's no reason to think it's the center of the lower bout.

As Grumpy says, the difference (in the Martin designs) is not all in bridge placement. In the OOO's, it's more in the extension of the upper bout, with some downward change in bridge position. In the O's and OO's, it is relatively more in bridge placement.

Other important factors:

the body is longer and has more air volume, which translates into lower main resonance and a change in the dipole resonances.

The neck being shorter is more rigid (less loss to neck vibration) and has a higher neck resonance. Which can (as Al regularly points out) lead to more bass if the neck resonance (usually to low to reinforce the bass notes) is moved up closer to the lowest notes on the guitar.

Other than sound, many players find the ergonomics of a 12-fretter better--their fretting arm can stay closer to the body. It's one of the first things I ask if someone is having elbow or shoulder trouble.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Oh, yeah, also: In an X braced guitar, if the bridge is moved toward the tail, the X will need to be closed some to keep it crossing under the bridge wings. The whole bracing pattern gets some adjustment.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Right. If you change the body length along with the neck length, the bridge can stay in the same place, as long as it's correct for the scale length. If you change just the neck length, then you get something like Martin's Norman Blake. Here's a pic I posted awhile ago that might illustrate. From the left, a 000-28 14-fret, Norman Blake 000-28 12-fret, and original-shape 000-28. A 14-fret OM might have helped here.



The location of the waist of the NB with respect to the nut, being the closes of the three, has prompted me to build a NB-type body because of my left shoulder condition.

I wonder if the "sweet spot" idea comes from the fact that most 12-fret guitars have more soundboard between the bridge and the soundhole.

When Martin went from the 12-fret to the first 14-fret OM, they made the neck longer and squashed the body, sort of a double cutaway, if you will. I think the first OMs must have looked very strange at first.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Oops. Can't wait for that edit button!

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now known around here as Pat Foster
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http://www.patfosterguitars.com

I kinda prefer 12 fretters. I like their look and their sound. I don't miss the access to the two extra frets since I don't venture to far past the 12th fret in my playing style.

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Guitars, guitars and more guitars.

I've only built one 12 fretter, but it is so far the best sounding guitar, to my ear, I have made. I split the difference and increased the upper bout enough to make up one fret difference and moved the bridge back to make up the other. I also like the shape of a 12 fret dred a lot -round shoulders and longer. Much better proportions to my eye than a regular dred. I have made a lot of 13 fret guitars, SJs and 000s for fingerstyle, and I think they are a good compromise, putting the bridge in a good spot without limiting access to upper frets too much.

                       Paul

As Howard said, it's likely that a lot of the tonal difference between 12 and 14 fret gutiars has to do with the body length. A longer body drops the pitch of the A-1 air resonance and changes the way it relates to the rest of what's going on to shape the sound.

If baseball bats can have a 'sweet spot' based on the physics of their vibration and such, I guess guitar tops can. The way I see it, though, you can move that spot around a lot by the way you do the bracing; it doesn't have to be at the widest point of the lower bout. For violins the 'sweet spot' is closer to the narrow point at the waist, and there are good reasons for that which could apply equally to a guitar with a braceless top, assuming you could make one.

Where exactly does the 13 fret models fit in. Why are they used, success?, and why 13 fret is chhosen over 12 & 14?

What advantages/disadvantages are there for each AND what scale is usually chosen for 13 fret?

13 fret guitars a pretty rare and I would consider them experimental which means that you aren't likely to find any consistency in the other parameters. I think the main reason for the 13 fret guitar is the "cut the baby in half" approach. You want to get some of the qualities of 14 fret and some of the 12 fret.

I've made a 13-3/4 fret guitar but that was because I had a lot of trouble getting the neck set properly.

I personally, would do a 24.9 scale on a 12 fretter but doubt that there is much correlation between frets clear of the body and scale length.

Thanks to all for the great info. (as always)

Have a look at SCGC's 13 fretter. A very sweet guitar.

H13

They've been building these for a few years.

A little history behind their H13...

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now known around here as Pat Foster
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http://www.patfosterguitars.com

McAlister builds a 13 fret.  I played one several years ago that he built for Rick Ruskin and it was very nice.

Greg Gwaltney also has built some that sound fantastic.

My impression is that, yes, they do kind of split the difference between the punch of a 14 fret and the sweetness of a 12 fret.  But I didn't hear either of them next to a similar 12 or 14 so it's hard to say for sure.  Based on what I heard, I'll be building one soon though.

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http://www.chassonguitars.com