Intonation is the degree to which an instrument stays in tune across its full register. Proper technique is vital; crushing strings down to the frets or sloppy technique that doesn't efficiently move the string straight down to the frets forces notes sharp.

        If the nut is too high, the extra distance the string must be stretched to reach the frets causes fretted notes near the nut to go sharp. (Lower tension light gauge strings aggravate this problem.) Nut slots equal to fret height is the ideal. Check this by pressing each string down on the bridge side of the third fret, then see how much the string must move to reach the first fret. It should barely move at all. This is very inexpensive (about $15) to have done by a pro; as a bonus the guitar will play its best. Low action at the nut means lower action all the way up the neck.

        On guitars with single coil pickups, the guitar will never intonate properly if the pickups are too close to the strings. Their magnetic pull dampens the string's vibration, causing false overtones as well as choking sustain. For best results, lower the pickups before setting intonation, then raise them afterward checking for intonation problems.

        To set intonation, start with new strings tuned to concert pitch. (Check out G-tune, it's amazingly accurate, easy to use, & FREE.) Compare the harmonic at the 12th fret to the fretted note, they should be identical. If the fretted note is flat, the string is too long. Shorten the string length (moving the harmonic "over" the fret) at the bridge, re-tune the string, and repeat. If the fretted note is sharp, lengthen the string at the bridge, re-tune the string, and repeat. That's all there is to it.

        Avoid this mistake: Don't intonate using the harmonic at the 19th fret. It's sharp of the note from the tempered scale (the fretted note) by about 1.5 cents. Most people can't detect a difference of less than 3 cents, but there's no reason to build this error into your setup. If you do, your string length will be too short and the intonation will be slightly sharp.

        For intonation adjustments done at the nut, check out The Compensated Nut by Stephen Delft, Earvana's precompensated nut, and of course, Buzz Feiten's system.

        Tuning is a function of intonation, described above. (The better the intonation, the better a guitar can be tuned.) Tuning by ear is one of the most misunderstood aspects of guitar. It involves compromises, because each string must be tuned so all of its notes are as close to true as possible within the limitations inherent in the design of the instrument. I find tuning by ear, in addition to being a benifitial exercise in ear training and a time to meditate and focus, to give more pleasing results than using an electronic tuner. However, to the beginner I recommend the tuner exclusively.

        One common error is to tune using harmonics at the 7th fret. These harmonics result in frequencys slightly sharp of the tempered scale, so their use must be avoided when accurate tuning is the goal. Another is to tune one chord perfectly, expecting other chords to agree. This never happens; the closer one chord shape gets to perfection, the farther another gets out of tune. A more reasonable goal is to have all chords equally balanced.

        Wave superposition is a method some use to tune (incorrectly) by comparing for example the harmonic at the 5th fret on the A string to the harmonic at the 7th fret on the D string. When these frequencys are not identical, there is a pulsing, throbbing sound which slows down and stops as the frequencies align. This is the right method, but the 7th fret harmonic must be avoided. Familiarize yourself with this technique before expecting the tuning sequence below to work for you. The reason it works so well is its simple method of getting the outer strings in perfect tune, followed by using only those strings as datums, you tune from the outer strings in using only octave harmonics and unison intervals.

Tuning by Ear

        Start by tuning the treble E string to a reference tone. Tune the harmonic at the 5th fret of the bass E to the treble string, then the E at the seventh fret of the A string and the E at the 2nd fret of the D string to the harmonic at the 12th fret of the bass E. Tune the E at the 5th fret of the B string to the treble E, and the harmonic at the 12th fret of the G string to the G at the 3rd fret of the E string. Double check the 12th fret harmonics of the D & A strings to the D at the B 3rd fret & the A at the G 2nd fret.

        Your guitar is now as in tune as it's ever going to be. Enjoy!


Tone

        This article says everything about tone that there is to say. To summarize: There is no perfect tone. Instead of looking for "The Tone" you need to think about finding your place within the frequency spectrum. The key to finding your tone is simple: stop looking for it. Your tone will find you.