Guitar Intonation

[FRANK]

So I ve been in discussion with my guitar player about Intonation . I seam to remember that I first need to tune the open string first and then test it against the 12th fret actually fretting it up against the 12th fret sometimes finding a happy medium between the 12th and the 19th fret  . and his recollection was that you tune the open string and test that against the 12th frets harmonic and I had to disagree but am I wrong or are we both right whats your Advice for this conversation so that I can report back and share with my Stringed Musician friends .

[Paul Verticchio]

Hi FRANK (:

Either route gets you to the same destination.  It's six of one and a half-dozen of the other.

I use the harmonic as that positions my finger right over the 12th fret and provides me with an "instant" comparison of the same pitch (8va).  In my case, it's more of a matter of "economy of motion" than which way is more widely used.

Have a great day man! (:

[Brandon A]

Frank, you check the open note against the harmonic. Good luck

[FRANK]

So how can both be right when in one instance your stretching the string by fretting it ,and the other your checking just the harmonic by lightly touching the string and releasing it which dose not stretch the string like in the first instance .I would think that if you were to use both method's one would be slightly different than the other .??? I am also under the impression that in areas of the fret board it is useful to use the harmonic for tuning to pitch but I dont think this means the frets and the saddles are in the correct position ??? needing adjustment for Equalized temperament .. I just had this discussion last night so I am needing more clarification on the subject FF where are you .

[Ron Ellison]

Checking the open string against a harmonic only tests the strings integrity not the fretting or saddle placement. The simplest test is open string or 12th harmonic against the string fretted at the 12th fret. If all is correct they should read the same.

[Paul Breen]

Checking intonation compares a string that is not stretched, plucked open or at the 12th fret harmonic to a string that is stretched by fretting it at the 12th fret.

[scott gannon]

I try to go with open, light fret at 12, harmonic at 12. My 2c. Never tried 19th, just gave it a go, hmmm. I know a classic player or two that do not tune harmonic or unison except for tuning to one note across all strings as described in the Kamimoto book so they tell me. Seems the guitar has to be on in the first place. Yeah I know, outside of discussion, just got bee stung!

[harrison phipps]

Comparing the open string (or its octave harmonic) to the fretted note at the 12th fret and adjusting the bridge saddle to get the two to be the same note sets the intonation correctly only if you just play open strings and notes at the 12th fret.  If you want the notes in between to sound acceptable, the entire guitar must be properly adjusted in the correct order starting with the neck, nut, bridge curve, bridge height and lastly intonation.  With the guitar up to pitch (or whatever tuning the player uses) fret a string at the first and ~14th frets and observe the distance between the bottom of the string & the top of the frets midway between the two fretted notes.  If the string is setting on the fret, the neck may have a back-bow.  If there is a large gap between string & fret, the neck has a bow & hopefully a truss rod adjustment will compensate.  The neck needs a small amount of "relief" or bow but too much will make it difficult to play in tune.  After the neck is properly adjusted, the next step is to check the action at the nut.  Fret each string at the 3rd fret and observe the distance between the bottom of the string & the top of the first fret.  There should be only a slight gap.  If the string is touching the 1st fret, the nut slot may be too deep causing open string buzz, if the gap is more than the thickness of a piece of paper (or so), the slot needs to be cut deeper.  A too-high nut (I know many) will cause excessive stretching of the string as it is fretted-resulting in a note that is sharp.  Next step is to assure the shape of the bridge results in the strings conforming to the curve of the fingerboard.  Next set the height of the bridge to suit the player.  Only now does it make sense to set the intonation.  Open string or harmonic (personal choice) compared to the fretted note at the 12th fret & adjust the saddle until the two are the same note.  Keep in mind that the guitar is an even tempered instrument with the half steps between octaves evenly spaced resulting in certain chords sounding out of tune even after all adjustments have been made properly.

[Ned Knepp]

Of course, as Harrison pointed out, a complete setup schedule needs to be followed but I've always understood that the whole point of compensating a bridge was to correct for the higher pitch of stretched strings  in comparison to the open notes on the same string. To that end, I've only used the fretted 12th / harmonic 12th. I don't see how using the 12th / 19th check would correct intonation in comparison to open strings.