Loudness Unit (LUFS) Reference / Target Checker

Inspectable records

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

t7-083

Ledger rows

1

No ledger note is attached.

Review findings

The comparison concept is valid, but the instrument needs a documented gain-adjustment sign convention, an explicit pass tolerance, versioned provenance and effective dates for each target, and clearer labeling that these are nominal guidance/reference values rather than universal platform guarantees. Actual LUFS analysis remains out of scope as stated.

Formula and scope findings

• The gain-adjustment sign is ambiguous: if delta = measuredLUFS - targetLUFS, the gain needed to reach the target is targetLUFS - measuredLUFS, which is the negative of delta.
• The specification does not define a pass/fail tolerance. The vectors below assume pass only when measuredLUFS exactly equals the nominal target.
• The listed Spotify and YouTube values are commonly cited guidance values, not necessarily immutable platform requirements; platform normalization policies and targets may change.
• EBU R128 at -23 LUFS is a broadcast loudness target/nominal reference, not a platform-delivery target.

Unit assumptions

• LUFS means integrated loudness in LUFS/LKFS-equivalent units; LUFS values are treated numerically as dB-like quantities for differences.
• The gain adjustment is defined here as targetLUFS - measuredLUFS, in dB: a negative value means attenuate and a positive value means increase gain.
• Pass means exact equality to the nominal target because no tolerance was supplied.
• The supplied measured value is already an integrated loudness measurement; this checker performs no audio analysis or LUFS conversion.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The specification has no division or domain trap, but an extreme finite LUFS input causes the target offset to disappear through floating-point precision, and the instrument does not state finite-range or plausibility validation. The sign of the reported gain adjustment is also convention-dependent unless delta and corrective gain are kept distinct.

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": {
    "measured_integrated_lufs": -12,
    "target_platform_preset": "Spotify"
  },
  "expected_outputs": {
    "target_lufs": -14,
    "delta_measured_minus_target_lufs": 2,
    "gain_adjustment_suggestion_db": -2,
    "pass": false
  },
  "reference_data": {
    "Spotify_target_lufs": -14,
    "source_convention": "widely tabulated platform guidance value; verify current Spotify documentation"
  },
  "working": "1. Target = -14.0 LUFS from the Spotify table row. 2. Delta = measured - target = (-12.0) - (-14.0) = 2.0 LUFS. 3. Gain adjustment to reach target = target - measured = (-14.0) - (-12.0) = -2.0 dB, so reduce gain by 2.0 dB. 4. Pass test: -12.0 == -14.0 is false."
}

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