True peak: the headroom check LUFS does not replace
True peak estimates peaks between samples that can appear during reconstruction or encoding.
Diagnosis
- Read dBTP separately from LUFS.
- Check the final rendered file, not only the live mix bus.
- Leave margin when the delivery chain may transcode.
Decision
- Reduce limiter ceiling before adding more limiting.
- Re-render after sample-rate or codec changes that matter.
- Compare audible change at matched level.
Measurement boundary
A safe true-peak reading closes one failure mode; it does not guarantee a clean master.
Common failure: Using sample peak as if it were true peak can miss reconstruction overs.