dB SPL / dBu / dBV Converter mechanism

Model scope

The listed SPL, dBu, and dBV reference formulas are standard under the stated RMS-unit assumptions. The instrument is not sufficiently specified for its advertised dBFS and cross-domain conversions. It should either be narrowed to independent reference-scale conversions and same-domain linear ratios, or add explicit dBFS conventions and calibration parameters.

• 20log10(V1/V2) is correct for amplitude quantities such as RMS voltage or RMS sound pressure, but it is not the power-ratio formula; power ratios require 10log10(P1/P2).
• The specification claims dBFS conversions but gives no dBFS reference or formula. dBFS is relative to digital full scale and cannot be converted to dBu, dBV, or dB SPL without an explicit digital-to-analog calibration reference.
• Direct conversion between dB SPL and dBu/dBV requires a transducer, acoustic/electrical gain, and calibration relationship; the listed fixed references alone are insufficient.
• The input called 'reference level' is ambiguous because it is unclear whether it means the source reference, target reference, physical full-scale level, or a calibration offset.

Units and conventions

• Voltage inputs are RMS volts unless explicitly documented otherwise; dBu uses 0.775 Vrms and dBV uses 1 Vrms.
• Sound pressure is RMS pascals; SPL uses p0 = 20 µPa = 0.000020 Pa.
• dB SPL is a pressure ratio, while dBu and dBV are voltage ratios; they are not directly interchangeable without calibration.
• For dBFS, the linear ratio is interpreted as amplitude ratio to digital full scale: ratio = 10^(dBFS/20). No physical voltage or pressure is implied.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "source_scale": "SPL",
    "source_value_db": 94,
    "target_scale": "linear_pressure_ratio",
    "reference_pressure_Pa": 0.00002
  },
  "expected_outputs": {
    "pressure_ratio_to_p0": 50118.72336272725,
    "pressure_Pa": 1.002374467254545
  },
  "working": "SPL = 20log10(p/p0). Therefore p/p0 = 10^(94/20) = 10^4.7 = 50118.72336272725. Then p = 50118.72336272725 × 0.000020 Pa = 1.002374467254545 Pa."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The zero linear-ratio input produces an undefined logarithm and must be rejected. The instrument also has a convention-sensitive ratio direction and requires explicit source-scale branching to avoid confusing dBu with dBV.

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-tranche2/tranche2-results.json
• BOUNDARY_HAZARD_CATALOG.json