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Greetings OLFers,

It's hard to do an effective search on scale length, so forgive me for asking things that have probably been covered ad infinitum elsewhere.
My questions are as follows:

- When choosing the fret to body (i.e. 12 vs 14), does this affect your choice of scale length and if so, how?

-I assume that any scale length can be made into either a 12 or a 14 fret instrument, is this correct?

-How does scale length affect tone, tuning and playability?

-Do certain body styles go best with particular scale lengths?

Thanks, Beth

Good questions Beth. I'll be waiting for the answers also. Like you I have always assumed the fret to body, scale length, and body shape all comes down to where the bridge hits the body.

Should be an interesting talk.

_________________
Joe Beaver
Maker of Sawdust

I have sometimes read (usually in ads for a particular big box guitar, so may be hype) about a "short" scale length being better in some way or vice versa. But there must be some change that happens when a different scale length is used otherwise, why not just have one scale length. I feel like I must be missing some important (and probably obvious) point. I guess if I used my left brain, I would have to start thinking about the string length and it's cross section and how that influences the tension and theoretically, the playability and/or the distance of vibration and therefore the tendency to buzz at lower actions…..but it just gives me a headache. I am going to be very brave though, if one of our physics champions weighs in with some answers, and will focus with all my might . Seriously, I'm sure it comes down to the physics, and hopefully I'll be able to understand the answers (I took physics for poets in college….I was much better at chemistry, but there's not much need for that here).

It does not.



Correct. Neck length and scale length are totally independent.



Shorter scale is less tension (for a given string gauge), which iusually means a bit less volume, less overtones, and more fundamental. Tuning can be a bit more challenging with a shorter scale. However, the typical 1/2" difference in scale lengths is pretty minor. Chances are, you won't notice much difference, other than the softer feel and closer left hand reaches with the short scale.



I think shorter scale works best on smaller bodies (00 and smaller), though Gibson has made their J-45/50 type guitars work quite well. This is because less tension means less energy to drive the top, and that works better when the top is smaller and lighter.

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John

Thanks so much, John. It makes good sense!

Another consideration is where the bridge is located relative to the lower bout. The closer the bridge is to centered in the lower bout, the more "effective" area the top has.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Scale length also has a bit of effect on volume and timbre. Many people have a preference for the sound of a particular scale length. Descriptions of tone are necessarily a bit subjective, so take the following with a grain of salt. In steel strings, to my ear a 25.4 scale sounds bit clearer and more powerful than a 24.75 short scale, which sounds "warmer" and seem to me a little easier to control in terms of dynamics. Dan Erlewine has compared the sound of chords on a long scale to the sound of professional singers harmonizing, while the short scale chords sound more like traditional singers. Maybe this relates to the harmonics of longer-scale strings being a little more in tune with the fundamental.

A shorter scale make the frets closer together which can be helpful for people with small hands and/or suboptimal playing position. The strings on a short scale guitar, being a little looser, are easier to bend.

Perhaps because of a general preference for louder instruments, in recent decades longer scales seem more popular, sometimes even with parlor and 0 size guitars which traditionally had short scales.

If you can find similarly-built 000 (short) and OM (long) guitars to play side by side, you can do some comparisons and see what you think.

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Tim Allen
"Never hurry, never rest."

Scale length is indeed something that will have an effect on the guitar . All the braces are laid out per the scale length. Most scale lengths used on steel strings are based off the Martin scale lengths though there are others. Gibson used a 24.5 25.75 . in Martin nomenclature
24.9 is the short scale 25.4 the long.
000 and the smaller bodies often have the 24.9 scale though 25.4 was and is still used. Dred 12 strings may also use both. Martin had put a few 24.9 short scale dreds out.
so what does this do ? Longer scales will have an increased tension to the body , this may add to volume lighter stress come with the 24.9 after all the shorter the string the higher pitch it will have under the same tension. Then to add to the recipe you can play with brace width . In all the short scales most noticeable effect will be bridge placement.
scale length will make the size of the neck slightly different but the martin style of body would also dictate the neck , a 12 fret 000 has a longer body and shorter neck than a 000 14 fret . Gibson used 12 , 13 and 14 fret necks on the same body. That was a different philosophy than CF Martin. So you can use a 12 fret neck on a 14 fret body as long as you place the braces as per scale length used.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Long scale instruments can use slightly thinner (and therefor less "stiff" ) strings for a given tension, and will have less inharmonicity in the upper partials. This may be what Dan Erlewine was referring to when speaking of the singers.

Beth, I think guitar bodies have to be designed around the scale length. I would agree that small bodies are most adaptable to shorter scales, but it doesn't necessarily mean that they will be a quieter instrument. Instruments are also designed around string gages, and bridge placement is also a big factor.
Here are a few scale lengths and body shapes and sizes from some of my instruments.
This is a typical 25.4" scale Grand Concert 12 fret. Note the soundhole and bridge placement.



To turn this one into a 14 fret would probably mean redesign as you basically would have to take the extra frets out of the upper bout. Shortening the scale to 24.9" doesn't work that well either without moving the bridge forward and the soundhole also. Just not too practical for anything but 25.4" scale.

Here is a Concert size 24.9" scale 12 fret.



You might be able to get a 14 fret out of this one. You would have to move the soundhole and bridge. The bridge on the 12 fret placement is in almost perfect position on the top.
This happens to be my favorite scale length and with slightly lighter than lights is very easy to play, has low action, and is gentle on my tired old hands.

Here is my MJ-12 design. Scale length is 23" and it is necessarily a 14 fret instrument.



String gages are rather on the heavy side (somewhere around .066-.014), action is very low, and is also very easy to play. I also build a similar 6 string with a slightly higher action and lighter gage strings.
Instrument would have to be completely redesigned to make a 12 fret.

Here we have the parlor, 24.9" scale, slightly lighter than light strings also 12 fret, and also very easy to play.



It probably would be quite possible to make a 14 fret guitar with this box. Soundhole would have to be moved forward.

Finally, here is a comparative photo of the parlor, concert and GC.



Twelve or 14 fret necks can be made to any scale as you can see, but it usually requires designing the intrument. To design an instrument if you can't find a box that fits your needs, you lay out the scale length, then place the soundhole, usually around the 20th fret. You then sculpt the instrument around the 12-14 fret marker, soundhole and bridge.
Bracing is set after that, if you X brace, it is usually set somewhere from centered between the soundhole and bridge to forward of that. Ladder bracing is much easier, you set the bridge patch at the bridge, a brace somewhat behind it, and a brace forward and behind the soundhole. A second brace or popsicle stick is set forward of the UTB.
Think that about covers it all, and don't be afraid to experiment with your own designs. There is actually no mystique to this stuff. It's all logical...and FUN!

One point that is coming out is that the guitar body is based off the scale length. When I build I usually start with the fretboard. Scale length sound hole layout , rosette is all based off this part.
Don't let scale length cause you to over thing. You can put 12 fret necks on 14 fret bodies , Gibson has done this since they started , Martin did this with the Norm Blake series but as Hans points out , the scale length determines the critical points of the guitar.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Don't forget the sound hole only HAS to move if you leave the fret board at 20 frets. There's no real need for 8 unreachable frets on a 12 fretter with a 20 fret fret board (no cutaway) so you can lop a couple frets off and move the sound hole (and bracing) toward the neck if you prefer the look sound etc.

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Thank You and Best To All

I'm not nearly good enough to care much but i have read on numerous threads that longer scale lends itself to alternative tunings. Not sure why.

Of course, there have been nearly as many that say that is completely false.

Robert, the fact that longer scale guitars have slightly higher tension means that with the same set of strings as you tune down they don't get as sloppy. I use lots of lowered and open tunings (always down) and as a result I prefer longer scales. But as others have said, you can build a guitar with any number of frets clear of the body, any sized body and any scale length and it will probably work. Here is a very long scale (26.5) 000 sized 12 string that I tune to C or C# with very heavy gauge strings. Other than the reach between frets it is remarkably easy to play

I personally prefer longer scale for dropped tunings because of the extra tension. I find a low E dropped down to a D on a 24.9 a little too floppy. Not so much on a 25.4. Even more so with a slide.

I played a parlour for a couple of years with a 24.9 Beth. I didn't notice much difference in string tension. I've switched over and been playing with 25.4 scale guitars for a few years now. A short scale I built came back for a tune up and I was surprised how noticeable the lower string tension felt going back from a 25.4.

I've always accepted the general theory of scale length with respect to tone, timbre etc... as talked about above but in practice I just don't see it. I have short scale guitars that sound just as loud or louder then long ones, just as sweet, bassy, bright and so on. So personally I like short scaled guitars because they are easier to play, period. I will still however tell prospective customers the same theoretic stuff because well... It seems to make sense. Then I hand them a small short scaled parlor guitar which is loud with good sustain and it turns the theoretical world upside down

I think a few responses tapped into the fact that heavier strings contribute to sound character as does scale length. I am a relative newbie with under 20 guitars finished, but have experimented with scale length, body length, frets to body, etc. The "loudest"guitar I've built was a very short scale 24.625" 13 fret with a L-00 inspired body. I used 13-56 strings and a very low action. The owner likes old delta and piedmont blues and tunes oddly, and typically down.

I would like to hear some feedback on this idea but to my ear shorter scaled guitars have a quicker response.

As I stated my personal sample size is small. What I love about this craft is the experimentation and the wheels turning. Build away! That's my advice. T

Thanks so much, everyone. Hans, thanks for taking the time to post those examples and narrate so completely. These answers have helped me so much!

Welcome Beth.
Lots of good stuff here, and you can see that along with scale goes string gages. It's about making the instrument feel right, not too tight, not too rubbery in the strings. Any scale can be tuned up or down, depending on the strings you use. For example, the very short scale 12 string at 23" has the heavy strings so I can tune it to B.
I don't have any trouble with the 24.9" scale dropping the E to D with a .054" string. Depends on the tension you like. If it's a little floppy for you with a drop D, just put on a heavier string. I wish players would stop thinking there are only light, medium and heavy strings.
Yes, you can chop off frets and put the soundhole anywhere, but everything else is related, bridge, # of frets to the box, etc. I like to keep most soundhole centers just slightly north of the waist. It's part of sculpting the box. The parlor is the furthest back as that is what a parlor looks like. Same with the concert. My Grand Concert and MJ are about as far as I will move the bridge forward from the center of the soundboard lower bout area. Go too far and you are out of the sweet spot.
As far as loud, JF and Tim are right. Got nothing to do with scale length. My parlor is louder than my wife's 37 year old D35. Doesn't have the deep, muddy bottom end though...
One thing I might mention is that the shorter the scale length/heavier the strings, the more twitchy the tuning gets. My 23" twelve has special 18-1 tuners and is still pretty sensitive on the tuner buttons. The six is much better, but strings are a lot lighter too.

Many guitar players look at a 12 fret guitar and only see a shorter neck and think short scale. I like a shorter scale because I have small hands. I like a 12 fret neck for 2 reasons. One is it puts the bridge closer to the center of the lower bout. The other is I don't have to reach out so far on the neck to play. I also use an oval sound hole to give me more soundboard surface for the bridge to act upon. Than I X brace based on bridge placement. Designing a guitar is a lot of fun if you know the principles that are in play.