Intonation is out, but it’s perfect if I capo the 1st fret and tune it

Discussion in 'Hardware, Setup & Repair [BG]' started by THarp91, Apr 14, 2019.


  1. THarp91

    THarp91

    Dec 11, 2018
    Glasgow, PA
    One of my basses has been having intonation problems lately. For example, I’ll get the open A string and the 12th fret of the A string both perfectly in tune, but frets 1-7 will all be sharp. But I’ve found that if I put a capo on the first fret and get all the strings in tune, then the intonation is good all the way up the neck. Is this an issue with the nut? Do I need to get it filed or possibly just get it replaced?
     
  2. MattZilla

    MattZilla

    Jun 26, 2013
    CNY
    Filed maybe.

    Now that you've broken your fine-tune cherry you may be having to also look into compensated nuts like the earvana.
     
  3. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Possibly but let's do a couple things first:

    *Re-set (...or set) your witness points at the tuner posts, nut, and bridge saddles. This is mission critical.

    *Set your intonation by matching the 12th fret harmonic vs 12th fret fretted...don't use the open string. There are variations on the aforementioned process but's it's a widely-accepted industry standard.

    *Re-check your intonation in the suspect areas. You have a capo...a set of feeler gauges may come in handy if the issues persist.

    Edit: you may want to move this thread to the "Repairs" forum.

    Riis
     
  4. ixlramp

    ixlramp

    Jan 25, 2005
    UK
    It does sound like the nut is out of tune with the frets. It may be improperly positioned laterally, or have slots that are cut too shallow, or this may be caused by not setting the witness points of the strings.
    This is a commonly used method, but is actually sloppy and prone to error, and doesn't use the advantage of a tuner.
    I disagree it is an industry standard, it is more a common bad habit that has unfortunately spread and assumed to be right due to it's commonality: a vicious cycle. It may be widely accepted but that doesn't make it right.

    Here's the key point: This method is only for when you don't have a tuner, because it is a way of comparing the tuning of the open note, via it's 2nd harmonic, to the tuning of a fret higher up.

    The 12th fret harmonic, the 2nd harmonic, is exactly an octave above the open string, so is the same as using the open string, so will include the nut tuning error.

    Many basses have open notes that are out of tune with the frets, for various reasons, the common method will not detect this problem and will result in incorrect intonation due to the problem.
    The tuning of the higher frets is much more sensitive to intonation adjustments than lower frets, so checking tuning above the octave and up to the highest played fret is essential.

    If you have a tuner it is obviously best to use it to check the tuning of the open note and many frets up to the highest played fret.
    Intonation is not about harmonics, it's about gettng every played note along a string in tune, therefore it obviously follows that the correct method is to use a tuner to check the tuning of every played note along a string (but every 2nd or 3rd fret is good enough).

    * Use a tuner to observe the tuning of various frets from the 1st to the highest played fret / highest fret, maybe check every 2nd or 3rd fret, ignore the open note. Adjust intonation as best you can.
    * Now that the frets are properly intonated and tuned, check the tuning of the open note, if it's out the nut is the problem, or it may be a case of setting the witness points in the strings.
    * Until you fix the issue you will have to compromise to minimise the tuning errors when using the frets and the open string.
    * Once the nut is in tune with the frets, intonate by this better method but also check the tuning of the open note in this process.
     
    Last edited: Apr 14, 2019
  5. b/o 402

    b/o 402

    Jul 14, 2015
    DC & MD
    You said lately. If this problem wasn't present before, could be bad strings - it happens. Otherwise it's the nut as previously stated.
     
    sissy kathy, Turnaround and JZQuantum like this.
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