Source: https://guthlabs.ai/docs/instruments/dbfs-audio-level-calculator/implementation/

instrument implementation / implementation-contract

# dBFS / Audio Level Calculator implementation

A source-bound implementation contract for dBFS / Audio Level Calculator; 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**: t4-232

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero reference value produces a division-by-zero before the logarithm, so the instrument must reject the input or explicitly return an undefined result. Exact zero signal amplitude also reaches the logarithm boundary and must be represented as -Infinity rather than a finite dB value.

## 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_type": "amplitude",
    "amplitude": 0.5,
    "full_scale_amplitude": 1
  },
  "expected_outputs": {
    "dBFS": -6.020599913,
    "linear_ratio": 0.5,
    "headroom_dB": 6.020599913
  },
  "working": "A1/A2=0.5/1.0=0.5. log10(0.5)=-0.3010299957. dBFS=20*(-0.3010299957)=-6.020599914 dBFS. Headroom=0-(-6.020599914)=6.020599914 dB."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/dbfs-audio-level-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/dbfs-audio-level-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/dbfs-audio-level-calculator/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-tranche4/tranche4-results.json`