Odd Intonation Issue

[bockscar]

Hello everyone,

I recently built an JEM and it seems that ever since I finished stringing it and tuning it, it's been having really strange intonation problems that I just can't figure out how to fix them. Basically, the intonation at the nut and at the harmonic above fret 12 are perfect, but everything in between is just a little bit sharp at varying degrees. For example, Fretting low E at fret 5 will produce a slight A sharp. Fretting D at fret 5 produces a very slight G sharp.

Is this a problem with the frets being too high? Basically any time I try to play chords, it sounds awful.

[dpm99]

Here are some critical questions to answer that might get you some better help:

1.) Did you cut the fret slots yourself? If so, how did you do it? If not, who did?

2.) What size fretwire did you use?

3.) What string gauge are you using?

[DarkAvenger]

Are you tuning the harmonic 12th to the 12th fret or to open(the nut)

[Ripthorn]

This problem occurs for me most commonly when I have to press the strings too far the fret them, thus stretching the string further and producing slightly sharp notes. Check your action. String gauge and neck relief will also play into this. You didn't notice the problem with open strings or at the harmonics because you aren't depressing the string at all. If it's not that, the others above also gave good suggestions.

[SwedishLuthier]

If the nut has reasonable correct string height, you have finally encountered "the cures of the badly intonated guitar". This is why Buzz Feiten, Earvana, True Temperament and similar system exist. The guitar is simply to inperfect...

[Workingman]

It sounds like a set-up issue to me. If you have other guitars and they don't bother you this is not an issue of the inherent tuning problems of guitars. As Swedish Luthier pointed out, nut height is critical. Also a high action can cause notes to fret sharp. High frets and light strings and high frets will also cause this problem.

[bockscar]

1.) Did you cut the fret slots yourself? If so, how did you do it? If not, who did?

2.) What size fretwire did you use?

3.) What string gauge are you using?

I did not, I bought the neck premade. The frets are jumbo but I do not know more than that off hand. I am using light strings; 9's.

Are you tuning the harmonic 12th to the 12th fret or to open(the nut)

I am tuning to the harmonic directly above the 12th fret.

It sounds like a set-up issue to me. If you have other guitars and they don't bother you this is not an issue of the inherent tuning problems of guitars. As Swedish Luthier pointed out, nut height is critical. Also a high action can cause notes to fret sharp. High frets and light strings and high frets will also cause this problem.

It is interesting that you say that because A. My action is remarkably high, and B. The spot where the strings meet the nut seem awfully high. Since I have jumbo frets, higher than normal nut, and light strings, could that possibly be the reason I am seeing this issue?

[westhemann]

yes..the high nut slots and high action,not the jumbo frets

[dpm99]

Sound like the guitar is fine, other than some possible setup issues. Have you tried a softer touch? I have this problem a lot when I play with 9's, because I'm used to heavier strings.