Intonation problem...

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by ap1, Aug 7, 2006.

  1. ap1

    ap1 Member

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    ...with my SG. No matter how precisely set, individual notes played around the first three or four frets are sharp, sometimes up to about 10 cents. The problem is especially acute on the second through fifth strings. First position chords sound pretty bad. As I move up the neck, the sharpness decreases; the intonation becomes acceptable at around the 5th or 6th fret, and is near perfect from that point up the neck.

    The neck is fine, the action is not too high, the intonation is perfect at the 12th fret, and I'm not applying undue pressure when I play in the first position.

    Could it have anything to do with the string height at the nut? Sometimes it seems that I could bring it down just a hair, so I'm willing to do that if I knew it would solve the problem. Otherwise, could it just be a Gibson scale length issue?

    Any ideas on either the cause of the problem or how to eliminate it? Thanks.
     
  2. Guinness Lad

    Guinness Lad Silver Supporting Member

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    It probably is because the nut is cut too high. If it's sharp only in the first 3 or 4 frets this would point to a improperly cut nut.
     
  3. carbz

    carbz Supporting Member

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    Welcome to reality... Intonation will never be 100% accurate on a stringed instrument. Its one of the most frustrating things about guitars. There are methods to get it close but unfortunately your in tune or your not.
     
  4. ap1

    ap1 Member

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    I know, but the problem is particularly bad with the SG. My other axes don't suffer like this. And almost 10 cents sharp in some cases! That's intolerable; and it's why I think there's something over and above the usual intonation issues.
     
  5. ap1

    ap1 Member

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    So my suspicion may be spot on. I've never messed with nuts before - (what's the best strategy besides taking it to someone who knows what they're doing?), pop it off, file it down some, and glue it back on? Or get the appropriate tool (which would be...?) and take down each slot a little?

    thanks
     
  6. PaulM

    PaulM Member

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    I'll bet this is precisely what it is.

    Don't pop the nut off and file the bottom, get a proper nut file (although any *very* small file will do if you are good with your hands) and cut them deeper. The strings only have to be high enough to clear the first fret, anything more is just screwing up your scale length.

    If you cut too deep on a bone nut, crazy glue and bone dust will work in a pinch to re-fill the slot a little and let you re-file it.

    Also, if you don't have files, you can use wound strings as a "saw" but that won't help you much with B and E... just do what you can to make sure the bottom is round and smooth and the cut angles downward toward the headstock, away from the fretboard slightly so you don't get a buzz in there.

    Good luck.
     
  7. ap1

    ap1 Member

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    Great! Thanks for the tips.
     
  8. burchyk

    burchyk Member

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    Get that nut fixed by a pro luthier
     
  9. bettiefan

    bettiefan Member

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    You didn't mention if your frets are worn. Worn frets (and they will wear faster in the lower positions with most players) will cause intonation problems you can't fix. Get them dressed properly or replaced if necessary.
     
  10. ap1

    ap1 Member

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    The frets are in great shape; had it refretted not too long ago.
     
  11. ap1

    ap1 Member

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    I thought about that, but I guess I don't mind doing it myself. I certainly have enough know-how, confidence, and patience to cut a few slots. And there's always got to be a first time with this sort of thing. The worst that can happen is I cut too low and have to replace the nut. Then I'll bring it to my guy.


    The only thing that's not clear to me is this - there are a alot of suggestions about using a saw on the first two slots, and rounded files on the rest, since the latter will have wound strings in them (except for maybe the G) and will be susceptible to snagging or breaking if the slots are cut with a saw, since the cut willl be somewhat square. But on all the axes I've seen, there doesn't seem to be that much of a difference among the type of cut; it just seems that they get wider as they go from 1st to last (obviously). Maybe I just can't see the diff? Maybe this is more important on an acoustic?
     
  12. rooster

    rooster Member

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    I've put Earvana nuts into 2 of my guitars, and they pretty much take care of that problem.

    rooster.
     

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