Intonation Problem Diagnostic

What this tool is for

Interpret 12th-fret tuner error only after tuning, relief, and action checks. Diagnostic tools rank observations and controlled checks. They do not identify a defect from one symptom, and their safest output is often the next measurement rather than an adjustment.

Use it when you can describe the current state and need a defensible next check. It is not a shortcut around inspection: preserve the starting state, change one variable, and verify the result under the same conditions.

Before you begin

Install stable strings, tune accurately, verify relief and action, and compare the fretted 12th note with the open note or 12th-fret harmonic using consistent fretting pressure.

• Use a stable, tuned instrument unless the page specifically investigates tuning.
• Name the physical reference, unit, and test condition beside every important number.
• Keep the original measurements so any reversible change can be returned to baseline.

Input guide

Instrument

identifies the record so its result is not attached to the wrong instrument or work order.

12th-fret reading

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

String condition

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

String action

supplies a measured geometric quantity whose datum and resolution should be written down.

Neck relief

records neck curvature under the stated capo, fret, position, and tuning method.

Pattern

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

Input labels describe evidence, not targets. A placeholder demonstrates format only; it is never a recommendation for a particular guitar.

How the result should be read

Look for a repeatable per-string pattern. Similar errors across every string can indicate measurement, tuning, scale, or setup problems rather than six independent saddle faults.

Read priorities from top to bottom, but stop as soon as new evidence contradicts an earlier assumption. Save or print the result ticket with the entered conditions so another person can reproduce the decision.

Method and logic

The result interprets error direction only after setup dependencies. A sharp fretted note generally needs a longer speaking length; a flat note generally needs a shorter one, subject to bridge design.

The page keeps calculation and diagnostic claims deliberately bounded. Display rounding improves readability, while the underlying logic uses entered values; descriptive branches report relative tendencies and the evidence needed to confirm them.

Worked example

With the open E centered and the fretted 12th reading 7 cents sharp on an otherwise stable string, the controlled next step is a small saddle move away from the nut, retune, and retest.

The example demonstrates reasoning, not a universal setup specification. Substitute real measurements and repeat the final test before accepting the next action.

Assumptions and limitations

Old strings, excessive fretting force, high nut slots, magnetic pull, compensated systems, and limited saddle travel distort simple direction rules. The tool does not prescribe irreversible bridge relocation.

Instrument design, service history, measurement error, and player technique can outweigh a calculator or checklist. Where manufacturer instructions exist for the exact hardware, use those instructions and record the revision consulted.

Safety and stop conditions

Stop for abnormal resistance, cracking, heat, odor, electrical sensation, moving wood or joints, a measurement that cannot be repeated, or any step that would remove material without a confirmed cause. Secure strings and stored mechanical energy before hardware work. Refer structural, fret-cutting, mains-powered, or uncertain repairs to a qualified technician.

Related workflow

• Guitar Setup Wizard — Turn symptoms and measurements into a safe setup order.
• Fret Buzz Diagnostic Tool — Prioritize likely buzz causes by location, playing context, and measurements.
• High Action Diagnostic Tool — Separate relief, bridge, nut, and neck-angle clues before adjustment.

Open the related page that answers the next unresolved question; do not run every tool as if every system needs adjustment.