Source: https://guthlabs.ai/docs/instruments/sound-level-distance-attenuation-inverse-square-law/implementation/

instrument implementation / implementation-contract

# Sound Level Distance Attenuation (Inverse Square Law) implementation

A source-bound implementation contract for Sound Level Distance Attenuation (Inverse Square Law); deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t2-013

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not explicitly state that both reference and target distances must be strictly positive. A zero reference distance produces division by zero and an undefined logarithm, so an implementation without domain validation can fail or emit a non-finite result.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "reference_spl_db_spl": 74,
    "reference_distance_m": 2,
    "target_distance_m": 8
  },
  "expected_outputs": {
    "target_spl_db_spl": 61.96
  },
  "working": "d2/d1 = 8/2 = 4. log10(4) = 0.60206. Distance loss = 20 x 0.60206 = 12.0412 dB. SPL2 = 74 - 12.0412 = 61.9588 dB SPL, approximately 61.96 dB SPL."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/sound-level-distance-attenuation-inverse-square-law/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/sound-level-distance-attenuation-inverse-square-law/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/sound-level-distance-attenuation-inverse-square-law/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche2/tranche2-results.json`