Intonation at first position

[Johnny Danger]

I should preface this by saying that between my two guitars, one is definitely in need of a setup and I plan on taking it to a well recommended local guy. But before I do, I wanted to ask a few questions here so that when I do talk to the guy, I know what to expect in terms of what he feels needs to be done and/or try not to look like a neurotic noob worried about something that can't be controlled.

So in short: both of my guitars are pretty darn sharp at the first few frets. If I vary the pressure, it might be as much as a 1/4 step sharp. This is especially noticeable on the low E string when fingerpicking and using that low E as a bass note. It's especially, especially bad when that the low E is tuned down to D.

I thought perhaps it was the slots at the nut, but everything I read indicated 30 thousandths was the proper height at the first fret on an open string, and both check out just fine. Another check I saw was 10 thousandths at the first fret when you press down at the third fret. That checks out on both guitars as well.

Also, both guitars have good intonation at the 12th fret. The Masterbilt has higher action, but that one is going to get the full setup.

So basically, am I just being too picky? Is this just the absolute best it's going to be? Would fret work help to lower the frets and thereby reduce how much tension can be applied to the string?

[mirwa]

Assuming your action is not to high,
Assuming your nut is cut correctly,
Assuming you have the right amount of relief,
Assuming the saddle is intonated correctly for open string and 12th,
Assuming your fret profile is correct,
Assuming the manufacturer laid down the correct scale length,

Then intonation can be improved with a compensated nut, a good luthier can spot all the above in moments, so do not under estimate the advantages of getting a setup done.

Any of the above noted points can also cause sharpness of fretted positions.

Steve

[Howard Klepper]

There really isn't a correct action height at the first fret, since it depends on the player's preferences for action height elsewhere. The ideal nut slot height is the same as the line of fret top heights. So when you depress the string gently between the 2nd and 3rd frets, the clearance at the 1st fret should be as near to zero as possible without touching the fret.

It sounds to me as if your nut slots are on the high side.

[charles Tauber]

For a non-compensated nut, it is also critical to intonation that the strings break over the nut at the face of the nut adjacent to the end of the fingerboard. If not, the intonation will suffer, even if it is correct at the 12th fret.

1/4 step (25 cents) sharp is huge. I can't imagine wanting to play an instrument that out of tune. You should generally aim for constant fretting pressure, as fretting pressure can alter the sounding pitch.

[Johnny Danger]

Originally Posted by charles Tauber

For a non-compensated nut, it is also critical to intonation that the strings break over the nut at the face of the nut adjacent to the end of the fingerboard. If not, the intonation will suffer, even if it is correct at the 12th fret.

1/4 step (25 cents) sharp is huge. I can't imagine wanting to play an instrument that out of tune. You should generally aim for constant fretting pressure, as fretting pressure can alter the sounding pitch.

Yeah, the 1/4 step sharp is with my pressing about as much as I can just to see how off it could possibly be. So definitely not at the standard pressure I would be playing at. But even a standard fretting pressure puts it sharp enough for me to wonder.

I guess I was more or less just looking for confirmation that I wasn't crazy and expecting the impossible from a good setup and also trying to determine if the issue was with the nut or maybe the frets being too tall. I will have to get a time to go and talk to them soon.

[Ned Milburn]

A determination based upon your info is as said above: the nut slots are likely too high.

Fret a note on the WRONG side of the 2nd fret. Then fret the first fret, and look for the deviation from non-depressed string to first fret-top. There should be VERY little space - about 1/2 a high e-string thickness.

[karlitofingers]

Definitely not being too picky, the notes should be bang in tune if everything on Mirwa's list above it correct.

What guitar model is it?
And, are the frets worn at all??
If the frets are worn there's no amount of adjustment gonna cure it.

I find that the measurements you've described above aren't always the best way (I've used them in the past and got the measurement correct only to find the open string buzzing on first fret after lowering the slot). A good tech will be able to eye ball it and go as low as possible for the gauge of string fitted and neck angle etc, at least that's my opinion.

Charles mentioned the bottom of the nut slots and where the string is leaving the nut....although this is VERY important it will not affect fretted notes which is where your problem was.


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[charles Tauber]

Originally Posted by karlitofingers

..although this is VERY important it will not affect fretted notes which is where your problem was.

It can. It makes the distance from the "zero" to first fret wrong - typically too long. Doing so makes the pitch of the first fret sharp relative to the pitch of the open string.

[karlitofingers]

Originally Posted by charles Tauber

It can. It makes the distance from the "zero" to first fret wrong - typically too long. Doing so makes the pitch of the first fret sharp relative to the pitch of the open string.

Yes, of course, relative to the pitch of the other open strings it is a problem, it can affect tuning in that way.

So if the problem is occurring whilst open chords are being played then the nut can be a cause, but if the individual fretted notes are sharp then the nut is not the problem. The OP needs to figure out which one it is, I would suggest tuning each string so the 12 fret is in tune, and then playing frets 1-3, if 1-3 are sharp then the nut may be fine. I doubt the nut has been cut that badly that it would produce such a big difference.


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[charles Tauber]

Originally Posted by karlitofingers

I would suggest tuning each string so the 12 fret is in tune, and then playing frets 1-3, if 1-3 are sharp then the nut may be fine.

I'm not following the logic of your suggestion.

The most common situation is that the first few frets play sharp because the slots in the nut are too high. I'd start by ensuring that the string height at the nut is correct, theoretically the same height as the frets. If that doesn't substantially solve the problem, I'd look into other matters, such as nut and/or saddle compensation.

After ensuring the string height at the nut is appropriate, if you really want the intonation to be "good", I'd suggest you measure it, in cents, for each open string and each fret. Then you have a complete profile of the accuracy of the notes. From that you can determine if the nut or saddle need adjustment of position. If you graph the points, one changes the "slope" of the profile, the other the offset (ordinate).

[Ned Milburn]

Originally Posted by karlitofingers

Yes, of course, relative to the pitch of the other open strings it is a problem, it can affect tuning in that way.

So if the problem is occurring whilst open chords are being played then the nut can be a cause, but if the individual fretted notes are sharp then the nut is not the problem. The OP needs to figure out which one it is, I would suggest tuning each string so the 12 fret is in tune, and then playing frets 1-3, if 1-3 are sharp then the nut may be fine. I doubt the nut has been cut that badly that it would produce such a big difference.


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Huh...?!?

If individual fretted notes, especially near the nut, are sharp, then the nut being cut too high is often, if not usually the culprit.

Nuts from factory guitars, even multi-thousand dollar guitars, are rarely cut to proper depth and hence will often, if not usually, intonate sharp on the lower frets.

[karlitofingers]

The nut needs to be sorted first yes. Can't explain what I mean properly. I'll quit before I make things worse [emoji23]


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[MC5C]

I had a new nut installed by a pro tech when he did a neck reset on one of my archtops. He was offended it didn't have a bone nut, so he did it without asking. Three of the middle strings were so high they played noticably out of tune at the first fret. I couldn't do a neck reset on a 70 year old guitar but I can sure slot a nut better than he could, so I fixed it. I go with Howard Klepper's method, and Ned Milburn's method. Bare clearance over the first fret when fretted between the second and third fret. Since this is independent of any other setup step, I do it first.

[Hot Vibrato]

.010" at the first fret (when fretting the third) is way too high. It should be more like .001"-.002".

At .010", you will certainly have sharpness in the first few frets, not to mention an overall stiff feeling action. Another variable is the levelness of the frets. Many guitars have a first fret that stands taller than the others. This means that even if the nut appears to be cut properly, it's actually too high, otherwise the strings would rattle on the high first fret. The result is the same tuning problems and stiffness that result in not slotting the nut deep enough.

[Alan Carruth]

The discussion of nut compensation can get complicated, but the basis is simple. Even if the nut slots are no higher off the fretboard than the fret tops you still have to push the string down to fret it, and that stretches it a little bit. That increase in tension makes the notes go sharp. The effect from the nut gets to be less and less as you go up the fretboard, but, of course, the effect from the saddle increases. Overall, then, assuming a 'perfect' flat fretboard with precisely spaced frets on a rigid beam, what you'll see is that the first fret notes will be slightly sharp, and the effect becomes greater as you go up.

In theory you could displace the first fret back a bit toward the nut to get the fretted note to be correct. You'd need to do this for every string, and, since different strings stretch differently, the amount of displacement would differ, so you'd end up with a crooked fret. And then the second fret would still be out, so you'd need to move that, and so on.

An easier way is to move the nut up toward the first fret a little bit, and then change the tension on the string a tad to get the open string pitch of the shortened string back to what you want. In effect you've moved all of the frets back toward the nut by the same amount. Just as it's easy enough to slant the saddle to get the 12th fret intonation to be more or less right for all the strings, you can compensate each string differently at the saddle so that they all work pretty well.

Moving the nut alters the amount of compensation you will need at the saddle. As Charles said, if you plot out the line of out-of-tuneness of the notes it starts out low at the first fret and rises as you go up. Moving the nut toward the first fret drops the whole line by about the same amount, while moving the saddle back flattens the slope of the line. By doing both you should, in theory, be able to get thing perfect all the way up.

In practice it's still a guitar, of course. Relief of the neck alters the distance you have to push the strings down, and resonances of the top, in particular, can alter the pitches of individual notes. Still, I used this on a 12-string a few years back and got every note on it to be within three cents of 'correct', according to a good tuner. Even then it's still 12-tone Equal Temperament, with all of it's problems, but you have to start someplace.