This article explains how to adjust guitar intonation. Adjusting the intonation of your guitar is an important step in maintaining the overall playability and sound of your instrument. Intonation refers to the accuracy of the pitch of each string when played at different frets along the neck of the guitar. If the intonation is off, it can cause certain notes or strings to sound out of tune, particularly higher up the neck, even if the guitar is properly tuned. Luckily, adjusting the intonation is a relatively simple process that can be done at home with a few tools.
Before you begin, you will need the following:
- A guitar tuner
- An allen wrench or small screwdriver (depending on the type of bridge that your guitar has)
Step 1: Tune your guitar to standard tuning (E, A, D, G, B, E) using a guitar tuner. Note, if you regularly play with your guitar in an alternate tuning, you should adjust the intonation while in the tuning that you usually play in. For example, if you play in Eb standard (1/2 a step down), set the intonation while in this tuning. This is because intonation is tuning dependent. If you ‘intonate’ your guitar correctly for standard tuning, the intonation will likely be slightly off if you then tune to Eb standard, for example.
Step 2: Locate the intonation adjustment screws on your guitar. These are typically found on the bridge of the guitar, near where the strings are anchored. When turned, these screws move the saddles (the parts of the bridge where the strings sit), shortening or lengthening the portion of the string that is free to vibrate. The location and type of intonation adjustment will vary depending on the type of guitar and bridge you have.
Step 3: Starting with the low E, play the natural harmonic at the 12th fret and the fretted note at the 12th fret. The harmonic is produced by lightly touching the string over the 12th fret and plucking it, while the fretted note is produced by pressing the string down at the 12th fret and plucking it. The two notes should be in tune with each other, if not, you will need to adjust the intonation.
Step 4: To adjust the intonation, use the allen wrench or screwdriver to carefully turn the intonation screw for the string in question. If the fretted note is sharp (higher in pitch than the harmonic), you need to lengthen the string by turning the screw so that the saddle is moved towards the bridge (away from the nut). If the fretted note is flat (lower in pitch than the harmonic), you will need to shorten the string by turning the screw so that the saddle is moved away from the bridge (toward the nut). Whether you need to turn the intonation screws clockwise or anticlockwise to move the saddle toward/away from the nut depends on the design of bridge that your guitar has. After making any adjustments, re-tune the string and re-check the intonation. Re-adjust as needed until the fretted note and the harmonic are equal in pitch.
Step 6: Repeat step 3 (and step 4, if adjustments are needed) for each string, making sure that the intonation is correct for that string before moving onto the next one.
It’s always a good idea to check the intonation on your guitar every couple of months, or whenever you notice that the guitar is not playing in tune. With a little practice and patience, you’ll be able to adjust the intonation on your guitar in no time.
You should always check the intonation of your guitar when you change strings, particularly if you are changing string gauge, as this will have a large impact on intonation (you many also need to check your action and truss rod). Keep in mind that intonation is also affected by various other factors such as the quality and age of your strings, action, and even humidity and temperature.