How to set guitar intonation
The guitar intonation must be as precise as possible. For that, the vibrant length of the string must be proportional to the scale length, the action and string caliber. Without a proper intonation it’s impossible to reach precise and tuned notes along the fretboard. It’s important to check or change the strings and check the height of the nut, neck curve and guitar dynamic. Also the frets must be in good shape.
Most electric guitars, allows you to intone each string individually.
After tuning, you compare the obtained note with the note that you get while pressing the 12th fret. If its lower, you should make the string length shorter. If it’s higher, you should do the opposite. The adjustment must continue till both notes are the same.
An electronic tuner would be very helpful. If the note is lower, the tuner needle should be before “0” and if it’s higher it would be after the “0”. If you use your hearing, it’s better to use the harmonic on 12th fret instead of the natural string note. Most acoustic guitars have an immovable bridge, so the intonation adjustments should be in hands of a professional.
In Tune-O-Matic bridges, like the ones you find in Gibson guitar, you will need to loosen up the string to be able to reach the screw to make the adjustment. In other bridges like those on Fender guitars, that won’t be necessary,