Setting Your Guitar's Intonation

Do you have trouble getting your guitar properly in tune? Do you have trouble making those high notes sound sweet? - Ian Downing looks at a way to improve your guitar's flavour.

The guitar is an imperfect instrument when it comes to tuning. What I mean is, it is impossible to have every note on the guitar in tune at the same time. Surprised?

Why is THIS you might ask?

The strings on a guitar are closer to the fret board at the nut end of the guitar than they are at the pickup end. In other words: as you go up the neck from the nut towards the bridge, the strings get progressively higher off the fret board. So that at the first fret (near the nut) your strings might be half a millimetre above the frets, where as up at the 18th fret, the strings could be 2 millimetres or more above the frets.

What's the significance of THIS?

If your string is 2 millimetres above the frets at the 18th fret, in order to press the string down onto the fret, you'll have to stretch it 2 millimetres! This is going to pull the string out of tune, the note will sound slightly sharp. Where as at the 1st fret, where the string is only half a millimetre above the frets, the distance and amount of string stretch necessary to press the string to the fret, is negligible.

The result?

The higher up the neck (towards the bridge) you play the more out of tune (sharp) the notes will get.

What's the solution?

In order to combat this, most electric guitars have what's called adjustable intonation. This means that if you look at the bridge, each string has its own little piece (known as a saddle piece) that it sits on separate from the rest. These saddle pieces are usually adjustable in two ways. One, you can (usually) change the height of each string separately. This is used to make the height of the strings follow the curve of the fret board (if it has a curve). Two you can change the position of the saddle piece in relation to its distance from the nut (end of the guitar). Its this second adjustment that we are concerned with. As you move the saddle piece towards the nut, what you are actually doing is shortening the string. If you move it back, you lengthen the string.

What's the point of that?

If you move the saddle piece back (away from the nut), you'll lower the pitch of the string. Even when you tune the open string back up to pitch with the machine heads (tuning pegs at the nut end of the guitar), you'll find that the strings pitch relative to the positions of the frets has changed slightly. The result is that the notes up at the 18th fret won't be as sharp when pressed, but that the notes down at the 1st fret will be ever so slightly flat. When adjusted correctly you'll find that the notes up around the 18th fret will sound acceptably in tune (only the tiniest bit sharp) and that the notes down at the 1st fret will also sound reasonable (only the tiniest bit flat). When adjusted correctly (If the guitar is of any quality) most people will not perceive any sort of tuning problem.

If your intonation (the lengths of the strings) is not correctly adjusted, you'll find it very hard (if not impossible) to tune up the guitar accurately, no matter how you try, it still sounds a little sour (out of tune). You play a chord in one area of the neck and it sounds OK, you play it in another and its sounds out of tune.

How do I set the intonation?

Its not hard, but you need a a tuning meter. I strongly recommend, if you haven't already bought one, you splash out and get a good quality one. Saving a bit of money by getting a cheap tuner is never a good idea in my experience. You'll probably find it difficult to get accurate tunings, because the meters on the cheap tuners tend to jump around a lot, they won't settle long enough for you to read them accurately.

You must have brand new strings on the guitar, this is VERY important.

Start by plugging the guitar into the tuning meter. Then tune up the guitar as normal using the meter. Then starting on the low E string, play the harmonic at the 12th fret. Tune this harmonic to pitch in the normal way with the meter if it isn't already there.

Next, play the note (E) on the E string at the 12th fret and look at the tuning meter. If this is in tune, then you have no problem on that string. the harmonic at the 12th fret and the note pressed down at the 12th fret should both be exactly in tune at the same time. check back and fourth between them.

If the fretted note reads flat on the meter, this means that the string is too long and you need to move the saddle piece towards the nut end of the guitar slightly. If the note at the 12th fret is reads sharp, it means that the string is too short and you need to move the saddle piece back away from the nut end of the guitar slightly.

Remember to check that the harmonic is in tune!

Every time you adjust a saddle piece, retune the harmonic at the 12th fret to the meter in the usual way, and see if the note pressed down at the 12th fret is in tune. If not, readjust and test again until both it and the harmonic are in tune.

How do I move the saddle piece?

Bog off... I'm not telling.

No, what you need to do is look at your bridge. Different guitars have different systems for adjusting the intonation (length of the strings). Your standard Strat or Gibson type guitars have screws at the back of the bridge, one for each saddle piece. You turn the screw one way and it lengthens the string, the other way and it shortens it, very easy. Guitars with locking tremolo units usually have one of two ways of doing it, both are devilishly difficult to adjust. Basically, on most locking tremolos, there is no screw which adjusts the length of the sting as such. What you have are screws that hold the saddle pieces on position, when you loosen these nuts, the saddles will move freely. what happens is that as soon as you loosen the screw, the string tension snaps the saddle as close to the nut end of the guitar as it will go. You then have to force it back to the correct position under tension of the string, impossible to make micro adjustments. So here's one way to do it. Make a guess at how much you think the saddle piece need to move. Depress the tremolo arm to the point where there is little or no tension on the strings (they're slack). Loosen the screw slightly. Use a screwdriver to nudge the saddle piece back or forward as necessary. Re-tighten the screw, release the tremolo arm. Sound like a nightmare, it is, but its got to be done.

Didn't they have set it in the shop before I bought the guitar?

in my experience, most music shops (even many of the good ones), don't take the time to set the intonation on the guitars they sell (it is very time consuming). Sometimes the factory will set it up before shipping, sometime not.

But this is irrelevant really, because even if the intonation is perfect when you buy the guitar, it won't be in a years time. Guitars wear in, the wood changes slightly as it does and is also affected by temperature humidity etc... so you'll probably need to set the intonation (or at least tweak it) about once a year. Also, if you change your gage of strings, or change the height of the strings (the action), you'll need to reset the intonation.

Even if you have a rough and ready attitude towards your guitar and are not worried about it being perfectly in tune, you'll really need to get it set up before you do any recording. Slight imperfections in the tuning show up much more clearly in the studio, than they do live or at home (though I think live performances suffer too). You don't want to arrive at the studio start to lay down a track and then be told by the engineer or producer that your guitar is out of tune. You don't want to then spend the better part of an hours studio time setting the intonation. I'll tell you what's far more likely to happen, you'll end up playing someone else's guitar (or an in house one) instead, and your performance may suffer as a result if you're not used to the instrument.

One option is to take your guitar to your local music shop and pay them to set it up for you. But I think you'll find that if you set it up yourself a couple of times, it won't seem as difficult as it might sound.