MUED.

How to set a true-peak ceiling (and why −1 dBTP)

Once you know true peak can exceed sample peak (see True peak vs sample peak), the practical question is simple: what ceiling do I set on my limiter? For most masters, the answer is −1 dBTP. Here's why, and how.

Why not 0 dBFS

Setting a ceiling at 0 dBFS — or −0.1 dBFS on a sample meter — leaves no room for two things that happen after your limiter:

  • Inter-sample overshoot on playback: the reconstructed waveform can rise above your last sample.
  • Lossy encoding (MP3, AAC): the encoder reshapes the waveform and can push peaks higher still.

A little headroom absorbs both. That headroom is what a true-peak ceiling buys you.

Why −1 dBTP

−1 dBTP is the widely-used default, and it's not arbitrary:

  • It reserves 1 dB for inter-sample peaks and encoder overshoot — enough for typical program material.
  • It matches common streaming guidance: AES TD1008 recommends a maximum true peak no higher than −1 dBTP at the lossy codec input; Spotify asks for true peak below −1 dBTP. Apple asks for at least 1 dB of headroom, without specifying dBTP or true peak.

Two situations to nudge lower:

  • Heavily-limited, dense masters push more energy into inter-sample peaks — −2 dBTP is a safer bet before aggressive lossy encoding. Spotify explicitly asks for true peak below −2 dBTP when your master is louder than −14 LUFS integrated.
  • Spoken-word / podcast delivery specs sometimes ask for −2 dBTP outright.

If you're unsure, −1 dBTP is the safe default; −2 dBTP is the conservative one. There's rarely a reason to go above −1.

How to set it

  1. Put a true-peak limiter last in your master chain (a plain sample-peak limiter won't protect you — it can't see inter-sample peaks).
  2. Set the output ceiling to −1.0 dBTP as a starting point. For Spotify, keep measured true peak below −1 dBTP, or below −2 dBTP if your master is louder than −14 LUFS integrated.
  3. Confirm the limiter is in true-peak mode, not sample-peak mode (on some plugins this is a switch; on a dedicated true-peak limiter it's the default).
  4. Drive loudness with input gain into the limiter until it reads right on your LUFS check (see LUFS targets for streaming) — the ceiling holds the peaks while you set level.

Common mistakes

  • Ceiling set at −0.1 dBFS sample and assuming you're safe — that's not a true-peak ceiling.
  • True-peak metering off, so overs never show.
  • Chasing loudness by lowering the ceiling — the ceiling controls peaks, input/drive controls loudness. They're different knobs.

Takeaways

  • Set a true-peak ceiling, last in the chain, at −1 dBTP for most work; −2 dBTP for dense masters or podcast specs. Spotify asks for measured true peak below −2 dBTP when the master is louder than −14 LUFS integrated.
  • The ceiling protects against inter-sample and encoder overshoot; input/drive sets loudness.
  • Verify true-peak mode is actually on.

Part of the Loudness and true peak guide.

Sources