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intonation fretted vs harmonic

Discussion in 'Hardware, Setup & Repair [BG]' started by briandavismurph, Dec 12, 2017.

  1. briandavismurph


    Jul 1, 2013
    Tried to search and found nothing that applied. Recently got a peterson strobe tuner and checking the intonation, it's almost perfect [if I can use that word] when comparing the open string with the 12th fret [harmonic]. When I compare the open string with the fretted note at the 12th fret it's a little sharp [3 cents or so]. Does this seem right? I know it's not the end of the world but I am curious. Thanks for any insight.
  2. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    It depends on how high your action is. The higher the action, the more likely it is to be sharp when fretted.
    I always rely on the 12th fret note when setting intonation, since that's the one that matters the most, and you can hit the harmonic anywhere on the string.
    reverendrally and superheavyfunk like this.
  3. lz4005


    Oct 22, 2013
    The open string and 12th fret harmonic will always be in tune unless the string is defective.

    Matching up the 12th fretted and harmonic is how you set intonation.
  4. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    The open string and 12th harmonic will always jive unless your bass is possessed. You need to match the 12th harmonic and 12th fretted and get those to match by adjusting the bridge saddle. Once you've set the intonation, check the 5th, 7th, and 17th (fretted) to make sure you're within spec.

    96tbird, Beej and rwkeating like this.
  5. Just an additional note here. On a plain (unwound) guitar string, as they get older, they stretch in weird ways due to corrosion. So the open string can be in tune, but the 3rd fret can be flat. This is typical on the high E string on acoustic guitars. So, if you're going do the intonation on a guitar, do it with new strings. Basses are a little more forgiving, but beware of really old strings.
  6. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    I think old bass strings can be the same.
    I had an old set on my BTB that wouldn't intonate at the E string, because the saddle just wouldn't got back far enough.
    Changed to a new set, same diameter, and it intonated fine.
    reverendrally likes this.
  7. lz4005


    Oct 22, 2013

    I would say that falls under a relatively broad definition of 'defective'.
  8. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    A note of caution ...

    Peterson Strobe Tuners are deadly accurate, down to one tenth of 1 cent, that's a thousandth of a semi tone. That level of accuracy is enough to drive many users nuts as they try to chase perfect intonation.

    Having said that, generally an open string and its 12th fret harmonic will always be in tune. It's either the open string or 12th fret harmonic vs the fretted note at the 12th fret that you should compare. If it's off by 3 cents you can improve that my adjusting the intonation screw on the saddle. If the fretted 12th is sharp use the intonation screw to move the saddle further from the nut, if flat move it closer. Reset the witness point on the string, retune and check again. Repeat until it's right. Or, since you are using a Peterson, until it is close to right. Good luck and don't over obsess.
  9. briandavismurph


    Jul 1, 2013
    thanks to all on you replies, it all makes perfect sense now
  10. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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