# Normalization History Card Generate a shareable before/after report card for any loudness change: gain applied, LUFS, true peak, sample peak, loudness range, waveforms and third-octave spectral deltas. > Canonical page: https://elysiatools.com/en/tools/audio-normalization-history-card - **Category:** Media - **Keywords:** normalization report, loudness history, before after compare, lufs delta, true peak check, waveform compare, spectral delta, gain report, mastering documentation, level change card, ebur128, lra ## Overview A readable audit of what normalization did to your audio. Upload the file from before the change and the file from after it — a master before and after loudness normalization, a podcast pass before and after leveling, or any two stages of a chain — and the card measures both with a BS.1770-4 compliant meter, then lays the numbers side by side: integrated loudness, oversampled true peak, sample peak, loudness range (LRA) and duration, with the applied gain computed from the loudness delta. The waveform pair is drawn from the decoded PCM on a shared amplitude scale, so a level change or a squashed crest is visible at a glance, and a third-octave spectral comparison (long-term average spectra of both sides) shows which frequency regions gained or lost energy — a tip-off that more than pure gain was applied. The card ends with a verdict: faithful-gain when the change is a clean level move (loudness delta matches the peak delta and the loudness range survives), dynamics-compressed when LRA shrank by 3 LU or more, clipping-risk when the result peaks above 0 dBTP or 0 dBFS, and level-lowered / level-raised for plain downward or upward moves. Great for documenting delivery versions, proving a normalize pass behaved, or sharing an A/B with a client. ## Inputs - **Audio before normalization** (file) - **Audio after normalization** (file) - **Card title (optional)** (text): e.g. Single master - streaming v2 ## When to use - Verifying that a loudness normalization pass applied pure linear gain without unintended dynamic compression or inter-sample clipping. - Auditing podcast leveling passes to verify voice consistency, dynamic range reduction, and loudness standard compliance. - Delivering client-facing A/B mastering proof cards showing exact LUFS adjustments, peak headroom, and spectral balance differences. ## How it works - Upload the original audio file and the post-normalization audio file. - Optionally enter a custom card title to label your delivery version or production stage. - The tool decodes PCM audio and analyzes both files using an ITU-R BS.1770-4 meter to compute integrated LUFS, oversampled true peak, sample peak, and loudness range (LRA). - An HTML report card is generated featuring side-by-side metric tables, shared-scale waveforms, third-octave spectral deltas, and an automated behavioral verdict. ## Use cases - Auditing post-production loudness passes against target broadcast delivery specifications. - Comparing unmastered mixes against mastered deliverables to evaluate dynamic range compression and spectral alterations. - Creating documentation for audio batch processing pipelines to guarantee that automated normalization tools do not induce clipping. ## Frequently asked questions ### What audio formats and file sizes are supported? You can upload standard audio files up to 100 MB each for both the before and after inputs. ### How are the loudness metrics measured? Metrics are analyzed using an ITU-R BS.1770-4 compliant meter to calculate integrated LUFS, oversampled true peak (dBTP), sample peak (dBFS), and loudness range (LRA). ### What do the different verdicts indicate? Verdicts include faithful-gain for clean level shifts, dynamics-compressed when LRA drops by 3 LU or more, clipping-risk if peaks exceed 0 dBTP or 0 dBFS, and level-raised or level-lowered for simple directional moves. ### Why does the report include a third-octave spectral delta? Third-octave spectral analysis compares long-term average spectra across frequency bands to show whether equalization, saturation, or multi-band processing was introduced beyond linear gain. ### In what format is the final report provided? 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