Setting up Your Guitar - Intonation
"Intonation" refers to the pitch accuracy of an instrument. In the case of guitars - the distance from the nut to the bridge is where intonation is affected. As you fret a string higher up the neck, its tuning will change, and if your intonation is out, the string will sound more and more out of tune the higher up the neck you go. Several factors contribute to fretted instrument intonation, including depth of the string slots in the nut, bridge saddle position, and the position of the frets themselves.
The easiest and most common way to adjust your guitars intonation is by adjusting the bridge saddles. Most modern electric guitars have 6 individual bridge saddles, which can be adjusted up and down for string height, and backwards or forwards for intonation. Two of the most common bridges are pictured - a Les Paul and a Stratocaster. Both are adjusted by a small screw.
THE GOLDEN RULE OF INTONATION: Flat = saddle needs to go FORWARD, Sharp = saddle needs to go BACK. Remember this and you can't go wrong! Now, onto how to adjust...
You will need: A decent guitar tuner, and the correct sized screwdriver for your saddle screws.
First, tune your string to pitch with a guitar tuner. Next, fret the string at the 12th fret (one octave up), and see if this note is flat or sharp. This tells you which way to adjust the saddle, as per golden rule above! Next, loosen the string off, and adjust the saddle incrememtally forwards or backwards with a screwdriver. This process can take a few goes, as each time you adjust you need to then re-tune the string and check wether it is in tune t the 12th fret or not. Once you have done this for all strings your guitar should be perfectly in tune!