Action & Intonation on a classical

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by ap1, Feb 14, 2008.


  1. ap1

    ap1 Member

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    I'm trying to get an idea as to how these work together. The action on my classical (actually a Takamine hybrid) is about 2/16" at the 12th fret, a little more at the 16th. At the first fret it's .008. So it gets a little too high for my liking in the upper frets. In measuring string height at the 8th fret with a capo on the 1st and holding down at the 16th, I get .010. There doesn't seem to be any neck bow in either direction.

    The intonation is spot on if I compare each 12th fret harmonic with the respective fretted note (i.e. for each individual string). Yet in playing, say, an E chord at the 12th and comparing it with a first position E, it sounds just a hair sharp.

    I'd like to lower the action at those higher frets without completely throwing out the intonation. What can I do to accomplish this? Truss rod? Lower the notches in the saddle? I've never quite understood how intonation is adjusted on a classical.

    Thanks in advance,
    Alan
     
  2. Dana Olsen

    Dana Olsen Gold Supporting Member

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    Hey Alan -

    Most classical guitars do not have a truss rod, so no adjustment possible there. If I read your post correctly, it sounds like the "E" chord in the first position (lowest frets, low and high "E" and "B" strings open) that the G# on the 1st fret "G" string is sharp - right?

    That's a common problem, probably caused by the nut slot not being cut deeply enough. Do you have a good guitar tech in your neighborhood? sounds like you could use a setup on your classical. Make sure to tell the tech what the specific problem is so they know what to look for.

    Don't cut notches in the bridge saddle. On a classical guitar, the fretboard is flat, so the action is adjusted by sanding the bottom of the bridge saddle. The top of the saddle can be shaped to make the string come off the back of the saddle or the front by creating a wedge shape on the top of the saddle, like a compensated bridge saddle on an acoustic guitar.

    The only way to lower the action on a classical is to sand the bottom of the bridge saddle, unless there is some other larger problem, like the bridge is too thick and needs to be shaved down or the saddle rout needs to be cut deeper. Remember if you're trying to d this yourself that you have to hold the bridge saddle VERY LEVEL when sanding it, and remember also that we have a tendency to sand off more material on the "push" stroke (pushing the saddle away from your body) than on the return stroke, so KEEP YOUR EYES OPEN to avoid this.

    IMPORTANT: Lowering the action on a classical is a one way street - you can't put it back on once you've sanded it off, so PROCEED VERY SLOWLY or you'll have to replace the bridge saddle.

    If you haven't done this kind of work before you should take it to a tech. It's a simple, low cost job, but it's better done by someone who has experience, much better in my opinion.

    What's your location? Us TGP types can help you find a good tech in your neighborhood ... well, your city anyhow. (GRIN)

    Hope this helps, Dana O.
     
  3. ap1

    ap1 Member

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    Dana -

    Thanks a bunch for the tips. Actually, being a 'fake' classical (basically an electric/acoustic nylon string), this thing does have a truss rod.
    The intonation issue is that the E chord played on the 12th fret sounds a little sharp when compared with the 1st position E chord. I was thinking that the higher action at the 12th fret made for intonation discrepancies but my tuner sez everything's ok for each string. I don't get it.

    I should've known about shaving the saddle; makes a lot more sense. I could give it a whirl myself, but maybe the thing could use an overall setup. I'm in the Philly area.

    BTW, since real classicals don't have truss rods, how are neck issues dealt with?

    Thanx,
    Alan
     
  4. Dana Olsen

    Dana Olsen Gold Supporting Member

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    Hey Alan -

    I get it now. Well, I doubt the truss rod will change the intonation much. Mostly nylon strings don't need much compensation ... maybe try new strings?

    I find that you can tune a classical guitar a little tighter than an electric. I try to make all the open 4th's a little wide (like the open "D" string to the open "G" string), then check 'em against 5th's to make sure they're not too wide (like open "D" to 2nd fret on the "G" string, which is an "A").

    How about it, fellow TGP'ers? Anybody recommend a good guitar tech in Philly?

    Dana O.
     
  5. henry_the_horse

    henry_the_horse Member

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    What kind of genre are you using the classical guitar for? Do you play with pick or fingers? What gauge of strings do you setup the guitar with?
    Depending on the answers to those questions you would need a higher or lower action.
    Usually classical guitars come from factory setup with no relief and action between 8/64" and 10/64". Mine is luthier built and was setup for my playing with no relief and 5/64" action. I use hard tension strings and play with a pick in a jazz context and only for solo passages. If I use the pick for comping it buzzes so I strum with my thumb.
    archtop.com recommends an action of 6/64" for the 6th string and 5/64" for the 1st string.

    Regards
     
  6. The Pup

    The Pup Supporting Member

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    I find that intonation and tuning are some of the variables and compromises in playing classical guitars.

    Tempered tuning and a constantly adjusting playing technique and feel (read touch) makes playing classical a wonderful challenge.

    There are some luthiers who have made great strides in classical intonation...I applaud their efforts.
     
  7. henry_the_horse

    henry_the_horse Member

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    You are right. That is why classical guitarists spend a lot of years building their sound on long practice daily sessions and searching for the perfect strings and the perfect guitar without much compromising of the shape and materials.
     
  8. ap1

    ap1 Member

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    Mostly for classical and other fingerpicking styles; occasional pick use for single lines. Strings are medium gauge.
     
  9. ap1

    ap1 Member

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    Agreed. And yet it's still bothersome to, say, strike a chord in open position and have the same chord on the higher frets sound noticeably sharp; with single lines it's not so evident.

    But it's still not clear to me how intonation is set on a classical. If my 12th fret harmonic is sharp compared to the fretted note, how is that dealt with?
     
  10. The Pup

    The Pup Supporting Member

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    Your string gauge/tension may not be right for the guitar, your action may be too high...your fret positions may be slightly off, your neck angle and relief may be slightly off, your bridge and saddle placement could be slightly off, etc. How your guitar was designed, made and setup is quite crucial to getting satisfactory intonation...not to mention playing technique and tempered tuning issues. Also, over time, your guitar may change as the materials settle in to their new form.

    ...someone once said a guitar still thinks it's a piece of wood (tree) for the first 25 years. :)
     
  11. henry_the_horse

    henry_the_horse Member

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    If the strings are new and the fretted note at the XII position is different from the harmonic at the same position then you have to move to a higher string gauge. Depends of the quality of the guitar. Maybe the frets are not where they should be.
    Never use a chord up in the XIIth position with a high action to measure intonation. When will you use such a high chord voicing when comping anyway? You should trust the individual fretted notes at XIIth position instead of the chord.

    Judging by the style you play, I would go down a few 1/64s of inch on the action, and use higher gauge strings. You need more string mass for better intonation, you longer the string scale by moving the bridge, then the other solution is to fatten the string.

    How do you tune the guitar?

    Regards.
     
  12. ap1

    ap1 Member

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    Henry,

    The strings are new; the guitar is not top of the line, but it's certainly not a poorly made instrument.

    It's not that I use the chord at the 12th fret to check intonation - I do it on each string. Harmonic first, then fretted note. The fretted note on a couple strings is ever so slightly sharp, hardly noticeable to the ear, one or two cents tops on the tuner. But when I play a full chord up there, it's noticeably out of tune.

    I'll try heavier gauge strings, and then bring the bridge down a bit if the problem persists.


    Not sure if you meant how I go about tuning, or what tuning I use. In any case, I play in standard tuning and use a tuner.

    Thanks,
    Alan
     
  13. David Collins

    David Collins Member

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    Discussion on classical intonation could go on and on in a dozen different directions. It's important to say thought that intonation on a classical depends a lot more on your fingering skills than it does on a steel string. If your bridge is properly located and your string choice seems to work with your instruments and setup, and the intonation checks okay with a tuner, then you just have to learn how to tune your chords as you play. This can of course mean training your hand for different stretches and pressures in particular chord shapes with thirds and sixths, or simply reworking your arrangements. If you're trying to play an open E or C above the 12th fret, have fun. If chords like that are what you're referring to I would suggest rethinking your arrangements.

    Other than that, it's the usual. Good strings, (and with more sensitive classicals this can involve a lot of time finding the match for your instrument) and good setup. The nut should always be cut from the rough ballpark factories set them. Action set to your preferences, which typically ranges from low as 4-5/64" for some flamenco and jazz up to 10/64" or above for traditional concert classical performers. Then if the intonation is still inconsistent at the upper frets you would either need to reshape the saddle or experiment more with different strings.

    So I pretty much just agree with all the advice Henry has offered you. I would add though, that in my experience a top of the line instrument isn't at much lower risk of manufacturing errors than mid or lower level. Gibson and Martin have certainly had their share of misplaced frets and bridges, and I see it on every down to the cheapest imports. Just had a Fender acoustic in on Thursday that had the bridge positioned about 1/8" too far back to ever play in tune (about .260" total compensation). From what you describe I don't necessarily think something like this is your problem, but it certainly can't be ruled out by an instrument's brand name or price bracket.
     
  14. henry_the_horse

    henry_the_horse Member

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    Thanks David.
    Yet when dealing with a luthier you have the opportunity to appreciate his or her work before ordering the guitar to be made or by trying different guitars he or she already made. If you are not satisfied you can ask him or her to correct the problem. With guitar factories there is more probability of inconsistencies between guitars (of course this speaks badly of the factory).

    I asked how the guitar was tuned because I have found that many of the problems regarding intonation comes from bad tuning in the first place. Using an electronic tuner and tuning the open strings is a ticket to bad intonation, specially when tuning acoustic instruments using the tuner microphone. Tuning the open strings to a reference is fine if you play mainly at the lower frets. If you play scales and voicings up the neck then tuning the strings' harmonics is better, the higher the harmonic you tune the better. I recommend to use as high a harmonic as your tuner microphone can measure.
    Tune the strings in order, from the outter strings to the inner strings, 6th, 1st, 5th, 2nd, 4th, 3rd. Always tune the 3rd string last and be ready to make some compromises in tuning. I always tune the VIIth position harmonic (d4) on the 3rd. string flat, against the same d4 harmonic on the Vth position on the 4th string. I usually tune the 4th and 3rd string using the harmonics from the VIIth position instead of the Vth position harmonics from the other four strings. Tuning the VIIth position harmonic means you are tuning the fifths and not the octaves. So I end with the 4th and 3rd strings sounding a little flat. The open D or G chord usually end sounding tight because of the 5ths intervals on those chords are tuned higher. But then, I don't play those two open position chords that often. Those compromises make the higher position barré chords sound intonated. But then again I prefer perfectly tuned 5ths intervals and flat 3rds to the opposite. There are other musicians who prefer the opposite situation: lower 5ths and higher 3rds.
    As David said, intonation in classical context could go for days or never end at all. It has already been going for 600 years.

    Regards.
     
  15. ap1

    ap1 Member

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    Great stuff, guys. Much obliged...
     

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