Is my audio uploaded to a server?
No. Decoding, loudness analysis, normalization, and encoding all happen inside your browser using the Web Audio API and WebCodecs. Files never leave your device.
What does LUFS mean and which target should I pick?
LUFS (Loudness Units relative to Full Scale) measures perceived loudness. Common targets: -14 LUFS for streaming platforms (Spotify, YouTube, Apple Music), -16 LUFS for general podcast/voice, -23 LUFS for broadcast (EBU R128).
What is the Max True Peak limit?
True peak is the highest sample value, measured in dBTP. Setting -1.0 dBTP leaves 1 dB of headroom so lossy encoders (MP3, AAC) do not introduce inter-sample clipping. Use -2.0 dBTP for safer mastering.
When should I use each normalization mode?
EBU R128 targets perceived loudness via LUFS — the most accurate for mixed material. ReplayGain is similar but historically calibrated for music libraries. Peak Normalization scales the file so the loudest sample hits the target — fast but ignores perceived loudness.
What does Prevent Clipping do?
It caps the applied gain so the resulting peak does not exceed Max True Peak. If a chosen LUFS target would force gain that pushes the file into clipping, Prevent Clipping reduces the gain to stay within the headroom.
Why is there only a single Gain Change number?
Normalization is a static gain offset applied to the whole file. The displayed value is the difference (in dB) between the original loudness and the target. Negative means quieter, positive means louder.
How accurate are the LUFS metrics?
We apply a BS.1770-style K-weighting filter (high-shelf + high-pass) before computing mean-square loudness. The output is within ~0.5 LUFS of professional meters for typical material — ideal for browser-side normalization, not for broadcast certification.
What is the maximum file size?
200 MB. Decoding, analysis, and rendering all stream through memory rather than buffering the whole file twice, so long voice recordings still process responsively.