The problem with sample peak
Your DAW's peak meter shows the highest sample value in the file. That is not the highest value the signal reaches.
Digital audio is a set of points; playback reconstructs a continuous waveform through them, and that waveform routinely goes higher than any individual sample. Two consecutive samples sitting just under full scale can reconstruct to well above it in the space between them.
The consequence is concrete: a file showing −0.1 dBFS on your meter can clip in a lossy encoder, in a converter, or on a phone. Nothing was wrong with the file as a set of numbers — the problem appears when it becomes a waveform again.
What true peak measures
True peak, in dBTP, is the peak of the reconstructed waveform — measured by oversampling, exactly as ITU-R BS.1770-4 specifies.
It is always greater than or equal to sample peak. If both read the same, the inter-sample content simply happened not to overshoot on that file.
Reading it
| You see | What it means |
|---|---|
| Above 0 dBTP | The row turns and says clips. This file will clip on playback. |
| −1 to 0 dBTP | No headroom for a lossy encoder to work with. MP3 and AAC shift peaks around; files mastered this hot frequently come back over. |
| −1 dBTP or lower | The common recommended ceiling for anything headed to a lossy codec. |
There is nothing magic about −1. It is a convention that exists because it is usually enough; some delivery specs ask for −2.
When it clips
- Lower the ceiling on your limiter and re-export. A true-peak-aware limiter does this correctly; a sample-peak limiter does not, which is often how the file got here.
- Check what you are delivering to. A WAV going to a mastering engineer does not need the same ceiling as an MP3 going to a streaming platform.
- Do not "fix" it by turning the whole file down. That moves the number without changing what a limiter already shaped into the audio.
Not the same as loudness
A quiet file can clip and a loud file can have headroom. True peak and LUFS answer different questions, which is why DropWave prints both.