True Peak Metering & Intersample Peaks: Preventing Streaming Distortion
Many music producers observe their master track peaking cleanly at -0.1 dBFS on their DAW meter, only to hear audible crackling when the song is uploaded to Spotify, Apple Music, or YouTube. The culprit is intersample peaks (ISPs).
The Physics of Intersample Peaks
A standard DAW peak meter only checks the discrete digital sample values. However, when the consumer's DAC converts these samples back into continuous analog voltages using sinc reconstruction interpolation, the curved waveform between two consecutive sample points can swing significantly higher than either individual sample.
When streaming platforms convert 24-bit masters into lossy codecs (Ogg Vorbis, AAC, or MP3), the psychoacoustic filter banks introduce additional peak shifts of +0.5 to +1.5 dB. If a master was maximized right up to 0 dBFS, severe digital clipping occurs inside the decoder.
Best Practice True Peak Ceiling
Audio engineers adhere to ITU-R BS.1770 true peak metering guidelines, setting the final limiter ceiling to -1.0 dBFS True Peak (dBTP) for lossy streaming distribution.