Glossary
True peak
The real peak level including inter-sample peaks that appear after MP3 or AAC encoding, not just the sample meter.
True peak is the actual highest level a waveform reaches once it is reconstructed as an analog signal, which can be higher than what a basic sample peak meter shows. This happens because lossy formats like MP3 or AAC can create inter-sample peaks between the digital samples that a simple meter never measured during editing.
A track that reads as safely under 0 dBFS in an editor can still clip after being exported and compressed for a podcast feed, producing audible distortion that only shows up once the episode is published. True peak metering catches this by estimating those inter-sample peaks before export rather than after a listener hears the problem.
A common safety practice is limiting true peak to around -1 dBTP during mastering, leaving a small buffer below the absolute digital ceiling. Many loudness normalization tools and podcast hosting platforms apply this automatically, but checking true peak manually before uploading a final export avoids relying on a host to fix it after the fact, especially for episodes distributed across several apps and formats.