# 📐  L2 Spec — Duct Acoustics — wave propagation in ducts / silencers Mismatch-Only Spec

**ID:** `L2-269-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-269`](/artifact/l1/L1-269)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554053

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| L m | m | 0.1 – 20 |
| M mach | — | 0.0 – 0.8 |
| Snr db | dB | 0 – 40 |
| N modes | — | 1 – 32 |
| Freq hz | Hz | 50 – 10000 |
| N probes | — | 2 – 64 |
| Flow mach error | — | 0.0 – 0.1 |
| Duct geometry error | — | 0.0 – 0.05 |
| Liner impedance error | — | 0.0 – 0.3 |

## 2. Tolerance (ε)

**Type:** `fn`

```
17.0 + 0.25*SNR_dB - 15.0*liner_impedance_error - 30.0*duct_geometry_error - 8.0*flow_mach_error
```

## 3. Difficulty

| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |

## 4. Fingerprint

`1bce3ec254fe8a3c408643cb5c89818706deff0ef37f52b8ae5ab8eea53b657a`

## 5. On-chain Registration

- **Chain hash:** `0x2e71c27fd885e3dfd3f67559544982482020cb5aba45366a13a80eb6dc46a85c`
- **Chain tx hash:** `0x3c679fb0764e4f012308887b1b541fa39c44382ab7925e8c4a84f380457dec13`
- **Chain block:** `41554053`

---

## File Mapping

This bundle consists of: `L2-269-001.md`, `L2-269-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-269-001.md` | Source of truth — edit this | Human or LLM |
| `L2-269-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |

**Prompt for your LLM after editing this Markdown:**

> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.

_This Markdown was auto-synthesized from the catalog row for `L2-269-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._