Have you ever tuned your guitar meticulously, only to find that chords higher up the neck sound off? This frustrating phenomenon is often due to poor intonation. Intonation, in essence, is your guitar’s ability to play in tune with itself across the entire fretboard. Understanding how to intonate guitar is a crucial skill for any guitarist who wants their instrument to sound its best. If you’re noticing notes sounding sharp or flat as you move up the neck, especially after tuning the open strings, chances are your guitar’s intonation needs adjustment. This guide will walk you through the process of intonating your guitar, ensuring every note rings true.
Why Guitar Intonation Matters
Imagine a piano where some keys are slightly out of tune relative to others; it would sound jarring and unprofessional. The same principle applies to the guitar. Proper intonation ensures that each note you play, from open strings to the highest frets, is accurately pitched. When a guitar is correctly intonated, playing chords and melodies across the neck becomes a much more pleasant and harmonious experience. Conversely, poor intonation can lead to a consistently out-of-tune sound, even when the open strings are perfectly tuned. This issue isn’t uncommon as guitars, being physical instruments, are susceptible to various factors that can throw off their intonation.
Environmental changes, particularly fluctuations in temperature and humidity, are major culprits. These conditions can cause the wood of the neck to expand or contract, subtly altering string length and thus, intonation. String age and gauge also play a role; as strings wear out, or when you switch to a different gauge, intonation adjustments become necessary. Even under stable conditions, regular intonation checks are part of routine guitar maintenance, much like tuning your strings before each playing session. In fact, intonation adjustment is a key component of a professional guitar setup, a service highly recommended to optimize your instrument’s playability and sound.
Properly adjusted bridge saddles are essential for accurate guitar intonation.
Understanding the Mechanics of Intonation
Guitar intonation is adjusted at the bridge, the anchor point for your strings on the guitar body. Most electric guitars and basses are designed with adjustable bridges specifically for this purpose. These bridges feature saddles for each string, which can be moved forward or backward, effectively changing the speaking length of the string – the distance between the nut and the bridge saddle. By precisely adjusting these saddles, we fine-tune the intonation.
The fundamental principle of intonation relies on the octave. Ideally, the note fretted at the 12th fret should be exactly one octave higher than the open string. Similarly, the 12th fret harmonic should also ring at this octave. If these pitches align, that string is correctly intonated. Discrepancies between the fretted 12th fret note and the 12th fret harmonic indicate an intonation problem that needs correction.
How to Check Your Guitar Intonation
To check your guitar’s intonation, you’ll need an accurate tuner. Electronic tuners or tuner apps are ideal for this task.
- Tune the Open String: Begin by tuning your open sixth string (low E) to pitch using your tuner. Ensure it’s perfectly in tune before proceeding.
- Check the 12th Fret Harmonic: Gently pluck the string directly over the 12th fret to produce a harmonic. Observe the pitch reading on your tuner. It should ideally be the same note as the open string, but an octave higher.
- Check the Fretted 12th Fret Note: Now, fret the sixth string at the 12th fret and pluck the note. Again, check the pitch on your tuner.
- Compare the Pitches: Compare the pitch of the 12th fret harmonic and the fretted 12th fret note. Ideally, they should be identical.
Interpreting the Results:
- In Tune: If both the 12th fret harmonic and the fretted 12th fret note are in tune, your intonation for that string is good.
- Sharp (Fretted Note Higher): If the fretted 12th fret note is sharper (higher in pitch) than the 12th fret harmonic, the string is too short. You need to lengthen the string to correct the intonation.
- Flat (Fretted Note Lower): If the fretted 12th fret note is flatter (lower in pitch) than the 12th fret harmonic, the string is too long. You need to shorten the string to correct the intonation.
Repeat this process for all six strings to assess the intonation across your entire guitar.
Adjusting Guitar Intonation: Step-by-Step
Now that you know how to check your intonation, let’s look at how to adjust it. You’ll typically need a small screwdriver or Allen key, depending on your guitar’s bridge type.
- Identify the Adjustment Screws: Locate the intonation adjustment screws on your guitar’s bridge. These are usually located at the back of the bridge, behind each saddle.
- Adjust for Sharp Notes: If the fretted 12th fret note is sharp, you need to lengthen the string. Turn the adjustment screw to move the saddle away from the nut (towards the tailpiece of the guitar). Make small adjustments and re-check the intonation after each adjustment.
- Adjust for Flat Notes: If the fretted 12th fret note is flat, you need to shorten the string. Turn the adjustment screw to move the saddle towards the nut (away from the tailpiece of the guitar). Again, make small adjustments and re-check.
- Tune and Re-Check: After each saddle adjustment, retune the open string and re-check the intonation at the 12th fret. This is crucial as intonation adjustments can slightly affect the overall tuning.
- Repeat for All Strings: Work through each string, one at a time, until the intonation is accurate for all six strings.
- Fine-Tuning: Intonation is an iterative process. You may need to go back and forth between strings, making minor tweaks until everything is perfectly dialed in.
Use a screwdriver to adjust the bridge saddles, moving them forward or backward to correct intonation.
Initial Intonation Setup (Optional)
For a starting point, especially after changing string gauges or completely resetting your bridge, you can use a tape measure to roughly set the intonation.
- Measure Scale Length: Measure the distance from the inside edge of the nut to the center of the 12th fret. Double this measurement to find your guitar’s scale length.
- Set First String Saddle: Adjust the high E string saddle so that the distance from the inside of the nut to the center of the saddle is approximately equal to the scale length.
- Stagger Subsequent Saddles: For the remaining saddles, you can stagger them slightly backward, increasing the string length incrementally for the thicker strings. A very rough rule of thumb is to move each saddle back by roughly the string gauge thickness from the previous string’s saddle position, but this is just a starting point, and fine-tuning with a tuner is always necessary.
This initial setup is not a substitute for accurate intonation using a tuner, but it can get you in the ballpark and minimize the amount of fine-tuning needed.
Conclusion: Maintaining Perfect Pitch
Intonating your guitar might seem daunting at first, but with a little patience and the right approach, it’s a manageable task. Regularly checking and adjusting your guitar’s intonation is essential for maintaining accurate pitch across the fretboard and ensuring your instrument sounds its best. By following these steps, you can confidently tackle how to intonate guitar and enjoy playing in tune, no matter where you are on the neck. Consistent intonation maintenance not only improves your playing experience but also contributes to the overall longevity and health of your instrument.
