Clipping and true peak check online

Sample peak vs true peak

Sample peak is the loudest sample in the file. But the analog signal a DAC or decoder rebuilds passes between samples and can rise above them — these are inter-sample peaks. True peak measures exactly those: the signal is oversampled 4× and the peak is found on that denser grid (ITU-R BS.1770).

So a master with a −0.1 dBFS sample peak can easily have a +0.8 dBTP true peak — and crackle on a cheap DAC or after conversion.

Why −1 dBTP

Platforms re-encode your WAV into lossy formats (Ogg Vorbis, AAC, Opus). The codec changes the waveform and peaks grow after decoding. That's why streaming services recommend keeping true peak at or below −1 dBTP, and for very loud masters (louder than −14 LUFS) Spotify suggests −2 dBTP.

In the report, true peak above −1 dBTP is highlighted, and the normalization table shows that a platform can't raise a quiet track past that headroom.

Clipping: what the analyzer looks for

Clipping means samples hitting the digital ceiling, with the tops of the waveform cut off. The engine counts:

• clipped samples — at 0 dBFS (|x| ≥ 0.9999);
• flat tops — runs of 3 or more clipped samples in a row, i.e. real flattened peaks rather than single random touches;
• where it happens — with timecodes in the list of notes.

PLR and PSR — how squashed the master is

PLR (Peak to Loudness Ratio) is the difference between true peak and integrated loudness. The smaller it is, the harder the limiter is working: values below 6–7 LU mean a very dense master. PSR is the same in a short window and shows how compressed individual moments are, such as the chorus.

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