Source: https://guthlabs.ai/docs/instruments/absorption-reflection-coefficient-lookup-acoustic-materials/

instrument / verified-clean

# Absorption/Reflection Coefficient Lookup (Acoustic Materials)

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/absorption-reflection-coefficient-lookup-acoustic-materials/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/absorption-reflection-coefficient-lookup-acoustic-materials/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/absorption-reflection-coefficient-lookup-acoustic-materials/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/absorption-reflection-coefficient-lookup-acoustic-materials/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Audio, Music, Photography & Color

**Tranche**: tranche-7

**Evidence ID**: t7-091

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The lookup concept is sound, and the honest label appropriately states that published laboratory values differ from installed performance. NEEDS_REVIEW is required because the exact table source and edition, coefficient convention, specimen conditions, supported frequency keys, interpolation policy, and material alias/error behavior are not specified. The four vectors use exact table-key lookups; none uses interpolation.

### Formula and scope findings

- Lookup-only retrieval is the correct algorithm for displaying published absorption coefficients; there is no numerical formula to verify.

- The specification does not identify a particular published table, source edition, mounting condition, room-test convention, or frequency-band convention, so the returned value cannot be uniquely verified from the specification alone.

- Material-name matching and behavior for unsupported or synonymous material names are unspecified.

### Unit assumptions

- Absorption coefficient α is dimensionless and conventionally reported on a nominal 0.00 to 1.00 scale, although measured reverberation-room coefficients can occasionally exceed 1.00.

- Frequency bands are assumed to be standard octave-band nominal center frequencies in hertz, such as 125, 250, 500, and 1000 Hz; the instrument should not treat an arbitrary frequency as an exact table key unless interpolation is explicitly supported.

- The tabulated values are assumed to be area-normalized random-incidence/reverberation-room absorption coefficients, not impedance-derived normal-incidence coefficients.

- Values depend on specimen mounting, backing, thickness, installation, humidity, aging, and test method; those conditions must accompany a production table.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification supplies no actual published data table, so coefficient values cannot be independently verified from the instrument specification. The lookup also has exposed hazards at unsupported or extreme frequency inputs and at ambiguous unit/convention text unless validation and explicit unit normalization are implemented.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "material": "ideal rigid wall",
    "frequency_band_hz": 1000
  },
  "expected_outputs": {
    "absorption_coefficient_alpha": 0
  },
  "reference_data": {
    "material": "ideal rigid wall",
    "frequency_band_hz": 1000,
    "absorption_coefficient_alpha": 0,
    "source_convention": "widely tabulated standard value; ideal perfectly reflective boundary reference, octave-band convention"
  },
  "working": "1. Match the material key: ideal rigid wall. 2. Match the exact octave-band key: 1000 Hz. 3. Retrieve α = 0.00. 4. No interpolation or unit conversion is performed. This is the canonical zero-absorption reference entry."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche7/tranche7-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`