What Is an Inter-Sample Peak?
Published · updated · by Loopin
A standard peak meter only measures the exact samples in a digital file — but when that file gets converted to analog or a different format, the actual waveform can peak higher between those samples than the meter ever showed you.
Why this gap exists
Digital audio stores a series of discrete sample points, and playback reconstructs a smooth waveform between them. If two adjacent samples are both near maximum level, the reconstructed curve between them can actually exceed what either individual sample measured — a peak that's real in the reconstructed signal but invisible to a meter only reading sample values.
This is a genuine acoustic and technical phenomenon, not a meter malfunction — it's simply measuring something different from what a true-peak meter measures.
Why it causes real problems
A file that reads as clean on a standard peak meter can still clip during D/A conversion, or distort during a lossy format conversion like MP3 encoding, specifically because of this gap between measured and actual peak level. This is why a track can sound fine in your DAW and distort slightly after being converted for streaming.
The distortion this causes is often subtle rather than dramatic — a slight harshness or grain rather than an obvious crackle — which makes it easy to miss without specifically checking for it.
How true-peak metering solves this
A true-peak meter, denoted dBTP, oversamples the signal to estimate what the reconstructed waveform actually peaks at between samples, rather than only reading the discrete sample values. This gives a more accurate picture of what will happen during conversion or lossy encoding.
Most modern mastering limiters include a true-peak mode or a dedicated true-peak ceiling setting — use it instead of relying on a standard peak meter alone.
The practical target
Setting your limiter's true-peak ceiling to −1 dBTP leaves enough headroom to absorb this inter-sample effect safely, which is why this specific number shows up as standard mastering guidance across nearly every genre and platform.
Going right up to 0 dBTP, even if a standard peak meter shows headroom, is where inter-sample peaks most commonly cause audible problems after conversion.
How to check if this has already affected a finished file
Load a suspect file into a true-peak-capable meter or analyzer and look specifically for readings above 0 dBTP, even if the file's standard peak reading looks fine. If you find this, the safest fix is going back to the master with a proper −1 dBTP ceiling set, rather than trying to correct an already-exported file after the fact.
This check is worth doing on any master before final delivery, especially ones mastered without an explicit true-peak setting engaged.
Frequently asked questions
What's the difference between a standard peak and a true peak?
A standard peak meter only reads the exact digital sample values. A true-peak meter estimates the actual reconstructed waveform between samples, which can be higher -- this gap is what causes clipping during format conversion even when a standard meter shows headroom.
Why does my track distort slightly after converting to MP3 even though it sounded clean in my DAW?
This is a common symptom of inter-sample peaks -- the file measured clean on a standard peak meter but exceeded 0 dBTP in the reconstructed waveform, causing subtle distortion during lossy format conversion.
What true-peak ceiling should I use to avoid this?
-1 dBTP is standard mastering guidance across most genres and platforms. It leaves enough headroom to absorb inter-sample peaks safely during format conversion or D/A playback.