H1−H2: The Thickness Metric
H1−H2 (dB) = the amplitude difference between the first and second harmonics, directly reflecting vocal fold thickness.
This is a core metric in vocal analysis. Why? Thick vocal folds (TA contraction) → low harmonics are strong → H1 above H2 → H1−H2 is negative; thin vocal folds (CT stretch) → high harmonics are strong → H2 above H1 → H1−H2 is positive. The ideal range in the app is −3 dB to +8 dB (the green zone) — too thick or too thin both lose points.
Experiment 8 · Find the Balance Between −3 and +8 dB
Drag the slider to change H1−H2 (the height difference between the two lines); the green vertical band is the ideal range. Switch between three vocal fold states with one click and watch the line shapes: Chest (H1 high, H2 low, negative) → Balanced mix (inside the range) → Head (H2 high, H1 low, positive).
H1−H2 = the "thermometer" of vocal fold thickness. This is where the app's thickness balance score comes from, matching the TA/CT pendulum model. Related: TA/CT balance chart