H06 — Quality tiers
Crowd data is survey-grade at best — never implied Class 1 / engineering-grade.
Tiers (working)
| Tier | Meaning |
|---|---|
| A | Reference SLM / validated external mic + documented protocol |
| B | Supported phone model with experimental correction profile |
| C | App on unprofiled device; complete metadata; no major warnings |
| D | Import / incomplete session / reduced control |
| E | Manual / legacy / insufficient metadata |
Map honesty rules
- Show sample size + uncertainty
- Do not rank sparse sections as precise fact
- Do not hide device-quality mix
- Separate measured noise vs passenger perception
- Quiet-room check ≠ calibration
Confidence (multi-axis, not one score)
Acoustic level · frequency · journey assignment · device calibration · metadata · subjective
Detail
calibration & tiers · acoustic methodology · R3291 notes · measurement philosophy · public map