Sound & signal

True peak

True peak is the highest level a waveform actually reaches between the samples that describe it. A file whose every sample sits below the ceiling can still overshoot it once a player reconstructs the sound.

In practice

A file can read under the ceiling on every sample and still clip the moment a player turns it back into sound.

Nothing a DJ does in a booth fixes this, so it is a buying and preparing concern rather than a performing one. The useful habits are ordinary: leave the mixer some headroom rather than assuming a commercial file is safe, and treat a track that sounds brittle on a big system as possibly clipped at the source rather than as something the EQ can rescue. Mastering engineers ceiling at −1 dBTP for exactly this reason, which is why the loudest masters you own still leave a sliver of room.

−1 dBTP

The mastering ceiling

0 dBFS

What a sample meter shows

Between samples

Where the overshoot lives

Where these come from: Conventional mastering targets and the arithmetic of reconstruction, not catalog figures. Our own reading cannot see this at all: we store an average level (RMS in dBFS) rather than a peak, so nothing we publish describes how close a track comes to the ceiling on any single sample. For what we can measure, see what happens when it goes over.

Why it matters

It explains a failure that looks impossible: a track that never reads 0 dBFS on any meter still distorting on a club system. The samples are only points on a curve, and the curve between two points can rise higher than either of them. The converter has to draw that curve, and if it goes above full scale, something clips.

It matters more on lossy files than on the master they came from, because an encoder redraws the waveform. A file that was exactly at the ceiling before encoding can come back out fractionally above it, which is why mastering leaves a decibel of room rather than filling the scale.

Frequently asked

What is the difference between true peak and sample peak?+

Sample peak is the highest value stored in the file. True peak is the highest value the reconstructed waveform reaches between those stored values, and it is always equal to or higher than the sample peak.

Why do masters stop at −1 dBTP?+

To leave room for inter-sample overshoot and for what a lossy encoder does to the waveform. Filling the scale exactly means any of those steps pushes the file over the ceiling.

Can a DJ fix true-peak clipping?+

Not in the booth. It is baked into the file. What you can do is keep headroom on the mixer so you are not adding to it, and prefer a lossless source where the encoder has not redrawn the waveform.

Related terms