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I think the 'correct' length can vary from one guitar to another by a little, so when I'm being fussy I'll do each string. Here's how:

Make a saddle with a flat top, and string the guitar up. It will buzz like mad. Take a short piece of leftover string, say a .012", and put it on top of the saddle crossing under one of the strings. Move it back and forth a bit until you find the right spot and mark it. Do this for each string. Take out the saddle and draw a line (or two)connecting the marks. File the front edge back to the line, then round off the back edge so that it comes to a peak at the line.

With a 12-string you'll find that the octave strings will need much different compensation than the regular ones, particularly the Gs. What I do on them is to connect the line of marks for the regular strings and those for the octaves. Then I file a V groove along the top of the saddle between the lines. Finish off the front and back edges of the saddle as for a six-string. Then use a small round file to notch out the sections of the saddle that you don't want the strings to touch. That is, for the G course, for example, you notch out the back ridge on the saddle where the octave string crosses it, and notch out the front ridge where the regular string would hit. Polish everything up before you put the saddle back in. This looks neat and gives you a 12 that will play in tune all the way up the neck. I find I need about a 3/16" wide saddle to do this, in most cases.

Note that you _must_ always do the rest of the setup first: the neck relief, action height and string gauges and brand may all have an effect.

IU had mentioned either in this thread or in another, that on the MIMF I pulled down a fret calc program that took into account string gauge, freq, nut and 12th fret action settings - I have been using it with great success on baritones and multiscale guitars. For a 24.9 with a 1/8 inch wide saddle, and a 3mm slant from high to low string on the slot, I use a comp of 2.5mm to the centre of the slot, betwen the G and D strings. This should give enough saddle to be able to get the intonation very close - sometimes the G needs a touch more forward, but its within a few cents. I will be on all future baris and multis though going to a 3/16 saddle now that I found a source for a 3/16 spiral downcut to route the slots.

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

Tony, would that be wfret? Or some other program I can't find? I'm going to be intonating a baritone soon, and that sounds handy...

No .. it was a zipped file called fretcomp, runs in Xcel

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

thanks for the replies,
i'll give a little backgroud on myself so you understand me a lil better.

i've been playing guitar for about 23 years now, havent had a whole lot of lessons, took some classical guitar music theory several years ago at a local college to help me. the teacher said i have great technique. back in the early 90s i took some lessons while i was in the Marines in southern california, but that was more scales and modes type lessons. the rest of my guitar experience is jamming with friends or playing in church, or just practicing on my own. there's alot i still dont know. i'm a "do it yourself" type of guy and learned to setup my electric guitars, but i always looking to learn something new i can do myself on my guitars.

with that being said..
I usually tune my guitars harmonically, then i play an Emaj chord and a few other chords to make sure its "in tune", then i'll run some scales up the fret board. i usually repeat this process until i am satisfied with the tune.

unfortunately i played the 12string two times got fed up with it and pulled the saddle out. then it sat there for a year, till now when i decided i wanted to finish the project. i just remember that i'd tune harmonically and play notes and i could never get the thing in tune.. if it was in tune harmonically it was out when i played chords, if i tuned it for first position Cmaj chord, next chord was out, and checking harmonically hurt my ears LOL.
the saddle bone i have is about 7/32" , which fit perfect in the bridge. i spent some time filing on the saddle rounding the ends to fit in the bridge, i radiused the back side of the saddle so it wasnt so sharp on the strings. .. i like alan's way of using the 0.012" string to help find optimum distance. if you guys think there's something else wrong, please let me know, thanks.
here are a couple pics of the bridge/saddle and the nut.



oh, and one other thing. a while back anticipating the project i was going to do on this 12 string, i bought an old conn strobotuner.. the thing works great! so i figure that will help nicely with this project.Speedz38833.8478240741

The guitar has a zero fret !!! the nut does nothing except hold the string spacing. If that fret is not in the right spot, the guitar is pretty much useless as far as getting in tune, no matter what you do at the saddle. If it needs to be moved (check with a micrometer), I would personally just take it out, route a proper slot for a std bone nut, and move on. Fill the existing nut slot with ebony or whatever.

The saddle looks more than wide enought o get the 12th fret intonation right.

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

Thanks Tony, yeah i wasnt thrilled about that either. what is the exact measurement that i'm supposed to have between first fret and Nut.. i just measured the zero fret to first fret.. 1.452" center to center.

depends !!! what is the true scale length !!!!!! (I dont see that mentioned in the posts)

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

Speedz:
If by 'tuning harmonically' you mean using 5/7 fret 'harmonics', that could be most of your tuning problem. The 7th fret harmonic is _not_ a tempered 12th above the fundamental of the string; it's too high. In fact, it's too high for two reasons:
1) On an 'ideal' string the 7th fret 'harmonic' would be at three times the pitch of the open string fundamental. Thus, for example, the 7th fret overtone on the A string (tuned to 110 Hz) would be 330 Hz, but your high E string _should_ be tuned to 329.6 Hz. There would be an almost two second beat frequency. If you use 5/7 'harmonics' to work your way up from the low E you've accumulated quite an error by the time you get to the B string.
2)The stiffness of the strings can shift the overtones upward from their 'theoretical' harmonic ratios. This will vary depending on a lot of stuff, like the way the string is built and how tight it is.

There is one effect that can lower the overtones: coupling with the top. However, it can also _raise_ them, and it's impossible to predict exactly which it will be. It varies from one guitar to the next, and from note to note. I recently tested this out with an A string. I mounted it on a rig I've made that is really solid, and can be clamped to the bench for even more mass and stiffness. Then I swapped it to a guitar. On the rig the overtones of theopen A string got higher as you went up, but on the guitar the lower two or three were actually shifted downward from what they theoretically 'should' have been. In that case the differnce might have been enough to make the 7th fret overtone 'true', but you can't count on that.

25.5" scale length.. i did a search from google for this model.. didnt find anything about scale length.. but i measured from zero fret to center of the saddle between D and G strings and got 25.5"

tuning with harmonics. i use 12th and 7th fret for tuning harmonically. octives.

either way when playing chords, within the same position.. (tuning with electronic tuner), the different chords sound out of tune between each other.
Speedz38834.8432060185

Hi Speedz .. I will give you a couple numbers to check.

The first to second fret distance in 25.5 is 1.3509 inches. In 25.4 its 1.3456. Check these to see which is closer, but as you can see there is very little difference. The nut to first fret is then 1.4312 in 25.5, and 1.4256 in 25.4. If it were me, I would be shortening this distance by about 40-50 thou, this will provide an averaged comp at the nut and sweeten the first position chords.

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

Thanks Tony, i'm pretty sure i have a 25.5" scale length. i re-measured the 0-1 distance and got 1.442 (but i set the calipers at 1.4312 and it looks like that could be right as well) its definately not the 24.5 SL.. i got 1.355 for the 1-2 fret measurement.

to be honest, i dont spent a lot of time in the first position when playing, i'm usually all over the fret board, i know the 12 string is usually a rhythm instrument, but i usually go between rhythm and lead and then do chording in other positions.

i just want to do whatever will make this guitar sound great whatever position i play it.

thanks,
Richard

If you capo the first fret, how well does the guitar play, in tune wise ??? Now the nut (zero fret) has nothing to do with it ??? The only thing that affects the guitar now is setup, and saddle position ie intonation (assuming the frets are in the right spots !!!) If the guitar plays well with the capo, then I suspect the zero fret could be moved or replaced to improve the open position chords.

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

Speedz wrote:
<<tuning with harmonics. i use 12th and 7th fret for tuning harmonically. octives. >>

OK, so the 7th fret is the problem, as I said. The 12th fret will give you a pitch that is almost exactlythe octave, and the 5th is close to two octaves above the fundamental of the string. The 7th fret is noticably high of the 12th interval, and must be avoided on most guitars. I did buy one guitar where 5/7 fret tuning worked, but it was mis-fretted.....

thanks Alan, now i'm curious what is the best way to tune a guitar without an electric tuner? i'm too lazy to pull out my beast strobotuner.

tony
i'll have to string up the guitar. what should i do since i have that flat topped saddle currently? put a small guage string under the strings down the center of the saddle?

thanks for your guys help, i really appriciate it!

Speedz:
I can't tell you a 'best' way to tune, since everybody has a different method that seems to work well for them. Just don't use that 7th fret overtone!

LOL the 5-7 and 7-12 harmonics are the only way i was taught to tune a guitar other than an electric tuner..

ultimately the ear is what decides whether its in tune when playing chords.

well i just strung the 12string. gonna try the capo on first fret and see how things sound.

Speedz; Colin's posted on this topic here a few times, searching the old discussions might turn it up, but there's also a nice method on the Ryan website (Ryanguitars.com) under 'News and Notes'->'Guitar Tech and Tips'

This is the method I've always used, all the strings are tuned to fretted notes and indeed all to E and, are tuned in accordance with equal temper, so that all strings contain the required amount of out-of-tuneness. It tends to take care of that annoying 2nd and 3rd string. This is the only method that my wife, an ex-professional classical violin player with perfect pitch, will allow me to use. Tune to octaves where necessary.

1. tune first string to E using reference tone or tuner.

2. tune 6th string to harmonic on the 5th fret of the 6th string (octave harmonic)

3. fret 5th string at 7th fret tune to 1st string.

4. fret 4th string at 2nd fret, tune to 1st.

5. fret 3rd at 9th fret tune to 1st.

6. fret 2nd at 5th fret tune to first.

This way the strings are all tuned to fretted notes to the same note and contain the "out-of-tuneness" for an equal temper.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

well i tuned it with my strobotuner, capo on 1st fret.. doesnt sound good. capo on 2nd fret.. sounds pretty decent. but i can tell intonation is off on the bass E string.. it goes sharp when held down at 12th fret.. so i'm assuming i need longer length. its octive string isnt too bad but still sharp..

i have it Bass E string tuned to D at 2nd fret with capo. i've got light guage strings on this 12 string guitar..
it looks like the bridge is pulling up/tilting forward so i tuned it down a bit... a few thousands gap :(

ohh, and thanks Colin i'll have to utilize that tuning procedure in the future, if you're wife is happy with it, i should be happy with it :)Speedz38838.0613425926

TTT