Ever noticed that your guitar sounds in tune on open strings but goes sharp or flat as you play higher up the neck? That's an intonation problem — and it's one of the most common issues guitarists overlook. Proper intonation ensures your guitar plays in tune across the entire fretboard, not just at the open strings.
What Is Guitar Intonation?
Intonation refers to the accuracy of pitch as you move up the neck. A guitar with correct intonation will play the same note in tune whether it's an open string, fretted at the 5th fret, or at the 12th fret. When intonation is off, chords that sound fine in open position become increasingly out of tune as you move higher up the neck.
What You'll Need
- A chromatic tuner (clip-on or pedal — the more accurate the better)
- A screwdriver (Phillips or flat, depending on your bridge)
- Your guitar in standard tuning with fresh strings
When to Check Intonation
Always check intonation after:
- Changing to a different string gauge
- Adjusting neck relief or saddle height
- A significant change in climate or season
- Setting up a new guitar
Step 1: Tune Your Guitar to Concert Pitch
Before checking intonation, make sure all strings are tuned to pitch. Use a reliable chromatic tuner and ensure the guitar is at room temperature — strings expand and contract with heat, affecting pitch.
Step 2: Check the 12th Fret Harmonic vs. Fretted Note
This is the key test:
- Play the 12th fret harmonic (lightly touch the string directly above the 12th fret wire and pluck — don't press down)
- Check the tuner — it should read exactly in tune
- Now play the fretted 12th fret note (press down normally)
- Compare the two readings on your tuner
- If the fretted note is sharp — the saddle needs to move back (away from the nut, lengthening the string)
- If the fretted note is flat — the saddle needs to move forward (toward the nut, shortening the string)
Step 3: Adjust the Saddle
On most electric guitars, each saddle has a screw at the back of the bridge. Turning it clockwise moves the saddle back (sharpens intonation), counter-clockwise moves it forward (flattens intonation).
Make small adjustments — a quarter turn at a time. Re-tune the string after each adjustment (moving the saddle changes the tension slightly), then recheck the harmonic vs. fretted comparison.
Repeat this process for every string.
Step 4: Acoustic Guitars
Acoustic guitar intonation is more complex because the saddle is a single piece. Minor intonation adjustments can be made by carefully sanding the saddle at an angle — but this requires experience and precision. Acoustic intonation correction is best handled by a professional luthier.
Common Causes of Poor Intonation
- Old or worn strings — always intonate with fresh strings
- Wrong string gauge — changing gauge without re-intonating throws everything off
- High action — pressing strings down too far sharpens the pitch
- Worn frets — uneven fret height causes inconsistent pitch across the neck
- Poorly cut nut — nut slot depth affects open string intonation
How Often Should You Check Intonation?
Check intonation every time you change strings or string gauge, and at least twice a year in Malaysia's changing climate. A quick intonation check takes under 10 minutes and makes a massive difference to how musical your guitar sounds when playing with others or recording.
Available at Reco Music Malaysia — free delivery for orders over RM100 to West Malaysia. Fast delivery nationwide. Contact us for more information.