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  • tallen 9:34AM

Intonation adjustment for just one string?



  • Thanks, there are some interesting points there. I'll see how I get on with it over Christmas. A bit more tinkering with it should give me a better understanding of how to fix it.
  • Jeff MooreJeff Moore Minneapolis✭✭✭✭ Lebreton 2
    edited January 2014 Posts: 476
    jonpowl is on to it, but let's get even further.

    Don't carve or alter anything yet.
    If your G is that far off, while the other are not (or ok) then buying different kinds of strings won't do that much. typically the heavier the string the sharper the fretted 12 fret will be compare to the the harmonic. Meaning and unwound G (like used for string bending rock) requires a longer setting to be intoned correctly.
    Don't file the bridge in such a way that you drop the G strings height below the other strings. It sounded like someone suggested this. Every bridge must adjust all the strings in all 3 dimensions. Up and down, back and forth, and side to side. You can't do alterations to any one dimension without accounting also for the other two.

    Before you alter anything at all, do this:
    Put your bridge dead center between the mustaches. See if any of the 12 fret (harmonic vs fretted note) intonations are perfect. If so, mark this on a quick sketch of your bridge. Now move the bridge back and then forth first a little one way then the other, (checking all the other strings) after each little move to see how their intonation is affected. Find "perfect" for each string. Don't be surprised how difficult this might be (hearing those harmonics over and over). When you find perfect for a string, mark the distance on your sketch that the bridge must be moved out of alignment (the distance measured from edges of the mustaches to edge of bridge for each string to be intoned.
    When you have the measurements as close as you can indicated on your sketch, make another sketch wear you add those corrections to the intonation you have on your current bridge, you'll begin to see what a intoned bridge would look like.
    How you finally get a bridge that matches the corrections that are now in your second sketch, with the intonation placement for each string correct is another matter, but at least you know what its gonna look like.

    My methods aren't endorsed by anybody else but result in really sweet sounding guitars. I'm a player (and a carpenter) not a guitar tech, but I've learned what I need to do the hard way.

    "We need a radical redistribution of wealth and power" MLK
  • Jeff MooreJeff Moore Minneapolis✭✭✭✭ Lebreton 2
    Posts: 476
    I wonder where the edit function went after posting? I'd like to retract the last statement I made about "buying better guitars". I've found I need to make bridges for guitars - period, but I don't really want to make such a global sounding critique of people who build guitars. They are amazing and of tremendous value to us all, and though I'm perplexed buy the standards of intonation that prevail, I don't want to undercut the value of our luthiers.
    Besides, I could be wrong and just have weird ears that hear a different "perfect". I also understand that my methods aren't accepted. That's ok with me, but I don't want to come off as down on luthiers. I'm not. They make the sounds I want to play and do so with tremendous skill and in a tough market. The bridge thing is a small part that I (at least) can, and don't mind, individualizing on my own guitars.
    "We need a radical redistribution of wealth and power" MLK
  • MichaelHorowitzMichaelHorowitz SeattleAdministrator
    Posts: 5,974
    Jeff, you can edit your post by clicking the cogwheel on the upper right of your post. Mouseover and you'll see it.

  • pickitjohnpickitjohn South Texas Corpus, San Antonio, AustinVirtuoso Patenotte 260
    Posts: 936
    I thought I made this post this morning and do Believe I saw it posted.

    Where did it Go? :shake:

    Hey Jay you said…
    I have a paper on correctly intonating a guitar. Done by a classical guitar playing physicist it is some 17 pages long with formulae to make your eyes water but it is correct. I have played one guitar set up this way and it was the best tempered guitar I have ever played.

    Is it possible to post the paper your referring to please.

    Thanks pickitjohn

    pick on
  • pickitjohnpickitjohn South Texas Corpus, San Antonio, AustinVirtuoso Patenotte 260
    Posts: 936

    I'm glad I'm not alone with the intonation thing. I'd have to say your solution of each string
    (the distance measured from edges of the mustaches to edge of bridge for each string to be intoned.)
    makes sense.
    Then according to other post about argentines being inconsistent it sounds like a lot of work for a Maybe Fix.

    I was watching a ebay auction for an Archtop Jazz Guitar Rosewood Bridge W Roller Saddles Adjustable Height


    I was wondering how this would sound.

    Has anyone ever tried one on a G J Guitar?

    If in the least it would give the references you were going for in your post.

    Any Thoughts?

    pick on

  • edited December 2013 Posts: 3,707
    Raising the action only accentuates the problems of intonation as it increases the stretch of the string. If one were to angle the bridge a bit to correctly intonate the B string then there could well be issues with E and G strings.

    Raising the action does not perceptibly change the length of the open string.
    The Magic really starts to happen when you can play it with your eyes closed
  • Jeff MooreJeff Moore Minneapolis✭✭✭✭ Lebreton 2
    edited January 2014 Posts: 476
    Thanks for the tip Michael. Dumb sentence deleted.

    The roller bridge in the picture has a fixed height for each string but the thumb wheels raise and lower the whole bridge. But yes you can fix the intonation on each saddle with a screwdriver with that arrangement.

    I've found that different kinds of strings don't require very much change in a bridge to account for the differences in mass and materials of whatever kind of string it is. The only kicker once you have a nicely intoned guitar is that if you try putting a unwound string where a wound one was used, like using an unwound G string that unwound G requires its own intonation to be practicle . That isn't likely on any acoustic guitar, but if you want to play blues rock on your Selmac with a .0017 (for instance) G string it'll be pretty out of whack when your playing high on the fret board.
    But the difference in intonation between Argentines and a light set of Bronze, or stainless, or whatever could hardly be noticed unless your using wildly light or heavy gauges.
    The difference between the usual types of strings for these guitars isn't usually gonna throw your intonation off enough to bother anyone but the perfectionist.

    Jay and PickitJohn
    Yeah the "correct" method of intonation takes lots of other things into account beyond just trying to perfect the 12th fret harmonic vs fretted note comparison. A "correct" guitar isn't in tune in any perfect sense, but tempered somewhat like a piano.
    But in the real world a guitar doesn't have to contend with the massive differences in string length and string construction like piano tuner does. A piano also plays notes closer to the extremes of human hearing and the tempering of a piano also has to account for how well we hear things at the extremes. A guitar only has the middle and upper octaves of our hearing to contend with. Much nicer.
    Next time your around a piano that has been recently tuned (tempered is the better word), just try playing simple triad chords in the center of the key board. They are out of tune enough to jangle a bit. A guitar can and should sound much more "perfectly" in tune than a piano.
    I find that by only using the 12th fret octave comparison thing yields a really consonant sounding guitar everywhere on the fretboard. The advantage of intoning this way also requires no math, no theory, can be described in a couple paragraphs, and works better. I was constantly irritated with the sharpness of my low E strings when playing chords way up the neck (not particularly on GJ guitars but acoustics in general. Particularly if the chord included open strings like playing a simple G chord at the 12th fret so the open G and D string are included with g, b, and g (again) at the 15th and 14th frets.
    I says: why? So I started making bridges that just account for the 12th fret thing. And Viola, everything sounded in tune! It took a lot of wasted saw dust to learn to make light, intoned, fitted and otherwise decent bridges, but now I can crank one out in a few hours with the simple jigs I've made. Part of what 12th fret intonation requires is more room on the bridge for intonation than exists on acoustic guitars. Like the typical bone (or plastic) saddle implanted on a fixed bridge acoustic, there isn't enough bone for 12intonation. The Selmac bridge barely has enough room. The low E will rest on the extreme back edge of the typical 3/4" wide Selmac bridge: Not very comfortably either. I build a wider bridge for that and other reasons.
    But doing this has become just part of what I want to do to get a guitar working right for me. It leaves me wondering: Is this just me? Is it just my ears? Don't others noticed their guitar plays pretty out of tune up the neck? Hasn't anyone tried the most obvious way to intonate. Why are the usual intonation "theories" not working for my ears?
    "We need a radical redistribution of wealth and power" MLK
  • edited December 2013 Posts: 3,707
    Great post Jeff. I will see if I can dig up that reference paper on bridge/nut adjustments. Although the math is a bit daunting, and the info necessary to do the calculations is hard to come by, you might find it of interest.

    As a sax player the whole temper vs just thing comes into play all the time. In sax quartet we play and tune beatless and as saxes (and other ww) have a bit of pitch variablility note to note well trained players adjust it automatically

    My Dunn selmac is as good as most any guitar gets in my limited experience. I do the final sweetening using chords and octaves where I do the most playing. My fan fret Dunn classiferri has, with the Tomastic classic steel strings, the best intonation of any guitar I have played.

    Interestingly, my Peterson strobe tuner has several acoustic guitar sweetenings
    The Magic really starts to happen when you can play it with your eyes closed
  • Jeff MooreJeff Moore Minneapolis✭✭✭✭ Lebreton 2
    Posts: 476
    Thanks Jazzaferri,
    Seems like all breathe driven instruments take more experience. The biggest difference I hear with high school and college bands when compared to the pros is the sweetness of sound, as in, in tune. Even a imperfect guitar if tuned carefully won't grate on you like the beginning wind player might. I love quartets of any kind if done well!
    Never tried Thomastiks.
    How hard is it to adjust to fans frets? Looks pretty hard! Every chord shape looks like it would require its own algorithm of shape shifting as you move up the neck.
    "We need a radical redistribution of wealth and power" MLK
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