# Intonation Diagnostic Tree

Logic rules for diagnosing pitch accuracy issues.

## Symbols

- `Sharp_12th`: Note at 12th fret is sharp relative to open string.
- `Flat_12th`: Note at 12th fret is flat relative to open string.
- `Sharp_1st`: Note at 1st fret is sharp (relative to open).
- `Sharp_All`: Notes are sharp everywhere when fretted.
- `Saddle_Forward`: Saddle contact point is too close to the nut.
- `Saddle_Back`: Saddle contact point is too far from the nut.
- `Nut_High`: Nut slots are too high.
- `Action_High`: General action is too high (stretching string when fretted).
- `String_Bad`: String core is damaged or inconsistent.
- `Pickup_High`: Magnetic pull from pickup is detuning the string (Stratitis).

## Logic Rules

### 1. Saddle Position (General Intonation)
**Condition:** `Sharp_12th`
**Logic:** `Sharp_12th → (Saddle_Forward ∨ Action_High)`
**Diagnostic Step:**
1.  Compare 12th fret harmonic vs fretted note.
2.  **Result:** If Fretted > Harmonic → Move saddle **BACK** (lengthen string).

**Condition:** `Flat_12th`
**Logic:** `Flat_12th → Saddle_Back`
**Diagnostic Step:**
1.  Compare 12th fret harmonic vs fretted note.
2.  **Result:** If Fretted < Harmonic → Move saddle **FORWARD** (shorten string).

### 2. Nut Height (First Position Intonation)
**Condition:** `Sharp_1st`
**Logic:** `Sharp_1st → Nut_High`
**Diagnostic Step:**
1.  Play open string (In Tune).
2.  Press 1st fret (gently).
3.  **Result:** If sharp > 5 cents → Nut slots need deepening.

### 3. General Sharpness
**Condition:** `Sharp_All`
**Logic:** `Sharp_All → (Action_High ∨ Fret_Crown_Flat)`
**Diagnostic Step:**
1.  Check if frets have a flat top (crowned improperly).
2.  Check if action is excessive (requiring large deflection to fret).

### 4. Warbling / Inconsistent Pitch
**Condition:** `Pitch_Warble`
**Logic:** `Pitch_Warble → (Pickup_High ∨ String_Bad)`
**Diagnostic Step:**
1.  Lower pickups away from strings.
2.  **Result:** If warble stops → `Pickup_High`.
3.  If persists → Change string (`String_Bad`).
