Peak Volume
Damian Moore, Last updated: 9 November 2026
Measures true peak: the highest level your audio reaches once it’s turned back into a waveform for playback, including the peaks between samples that a sample-peak meter misses. MP3 and AAC encoding can push it higher. Apple Podcasts asks for a true peak no higher than −1 dB, and ACX asks audiobooks for peaks no higher than −3 dB.
Sample peak vs true peak
Our peak check reports sample peak — the loudest individual sample stored in the file. True peak is the level the waveform can briefly reach between samples once it’s reconstructed for playback, measured by oversampling. These inter-sample peaks can exceed what the stored samples show, so a file that just clears -1 dBFS in Audio Audit can still overshoot slightly on playback or once it’s re-encoded to AAC or MP3. Peak also needs to be judged alongside loudness (LUFS).
Fixing peaks with Audio Audit
Audio enhancement includes volume normalisation, which brings the whole episode to a target loudness with a single, constant gain change and then applies a true-peak safety limiter (-1 dBTP on the Podcast preset). The limiter only catches the occasional stray peak — it’s a backstop, not a levelling tool, and does nothing when nothing exceeds the ceiling. If your speech has lots of uneven peaks, the compression stage evens out the gap between loud and quiet speech before normalisation. Neither can repair audio that was clipped when it was recorded, so get your levels right at the microphone. See Enhancing audio for the options.
The peak check is Required at -1 dBFS in all the built-in standards (Podcast, AES speech and EBU R128). If you need a different limit, you can change it in a custom standard.
Header photo courtesy of @chairulfajar_
