Loudness Unit (LUFS) Reference / Target Checker mechanism

Model scope

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.

• 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.

Units and conventions

• 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.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

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.

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json