Why Guitars Require Intonation Compensation

If you calculate fret spacing using Pythagoras's musical division rules, frets sit at mathematically precise harmonic fractions of scale length. However, when you press a guitar string down to a fret crown, you physically stretch the string downward, slightly increasing string tension and pulling the note sharp.

To compensate for this sharpening effect, the bridge saddle must be set slightly farther back than the theoretical scale length. Thicker strings require more compensation than thin strings.

How to Intonate with Precision

  1. Ensure neck relief, nut slot height, and bridge action are finalized before touching intonation saddles.
  2. Tune the guitar to concert pitch using a high-precision strobe tuner.
  3. Play the 12th-fret natural chime harmonic, then lightly fret the 12th fret note with normal playing pressure.
  4. If Fretted Note Is Sharp: The string is effectively too short. Move the saddle backward away from the nut.
  5. If Fretted Note Is Flat: The string is effectively too long. Move the saddle forward toward the nut.

Why the B-String and Low-E Always Sit Farther Back

Because plain unwound strings have solid steel cores, the plain B string has a larger core diameter than the core of the wound G string! This is why acoustic saddles and electric bridges always display a stepped zigzag pattern.