Sample peak — what your DAW shows

A digital audio file is a series of samples. At 44.1 kHz, that's 44,100 samples per second per channel. Each sample has a value somewhere between -1.0 and +1.0 (in normalized terms) or -0 dBFS and 0 dBFS.

Your DAW's peak meter shows the highest individual sample value in the file. If the loudest sample is at -0.1 dBFS, that's your sample peak. You can read it on any peak meter in any DAW.

That number is correct. It just doesn't tell you what's between the samples.

The thing your DAW doesn't show

Audio playback isn't a series of staircases. When a digital file plays, the audio system reconstructs a smooth analog waveform between the samples — interpolation. The waveform that comes out the speaker can rise above the value of any individual sample.

That higher value, the actual peak the audio system reconstructs, is called the true peak. It can be higher than the sample peak, sometimes substantially.

In a file where the sample peaks all sit at -0.1 dBFS, the reconstructed waveform between those samples can swing up to +0.5 dB or more in some cases. The peak the listener hears is +0.5 dB above the digital ceiling — clipping, even though no individual sample is clipping.

This is inter-sample peaks, and it's why true peak measurement exists.

How true peak is measured

The standard for true peak measurement is ITU-R BS.1770-4 Annex 2. It works by oversampling the audio signal — typically 4× oversampling — and then finding the actual peak of the reconstructed waveform.

The oversampling uses a specific FIR filter with coefficients defined in the spec. The peak of the oversampled signal is the True Peak (dBTP). Any audio meter or measurement tool that's true-peak-compliant runs this same algorithm and gets the same answer.

The free LUFS Mix Analyzer implements the BS.1770-4 spec verbatim — drop a file, get the true peak in dBTP, validated against iZotope Insight 2.

Why streaming codecs make this worse

If you only played your master back on a lossless DAC, the inter-sample peak situation would be manageable — most consumer audio systems have a small amount of internal headroom that handles minor over-peak situations cleanly.

The problem is lossy codecs. When Spotify encodes your file to Ogg Vorbis, or Apple encodes to AAC, or YouTube encodes to AAC, the encoder reconstructs the waveform and applies its own compression. That process can add inter-sample peaks that weren't even in your original master. A file with true peaks at -0.5 dBTP can come out of an Ogg Vorbis encoder with peaks at +0.2 dBTP — clipping in the encoded file.

Lossy codecs don't preserve true peaks. They can push them higher. That's why every streaming platform recommends a true peak ceiling that's well below the digital ceiling.

The right true peak ceiling

The widely accepted standard:

• -1.0 dBTP for streaming (Spotify, Apple Music, YouTube Music, Tidal, Amazon Music)
• -1.0 to -2.0 dBTP for lossless platforms (some prefer -2.0 for safety)
• No published ceiling for Bandcamp / lossless downloads — Bandcamp doesn't set one; -1.0 dBTP is still safe general practice
• More conservative (-1.5 dBTP or quieter) for podcast / spoken-word delivery

A true peak ceiling of -1.0 dBTP gives the streaming codec room to add its inter-sample peaks without clipping. The ceiling becomes part of the master's character — your limiter is set so the true peaks never go above -1.0 dBTP, which means the lossy encoder has roughly 1 dB of headroom to work with.

If you skip this and let your master sit at -0.1 dBTP true peak, you're sending the encoder a signal with effectively zero codec safety. The encoder will add peaks, those peaks will clip, and your listeners will hear distortion on lossy playback.

How to check your master's true peak

The free LUFS Mix Analyzer reads true peak alongside integrated LUFS. Drop your master, get the reading in seconds. If the true peak is above -1.0 dBTP and you're releasing to streaming, you have a codec-safety issue.

If you're mixing and want to check whether a pre-master bounce has hidden inter-sample peak issues, the Mix Readiness Checklist flags true peak as part of its automatic checks.

True peak limiting — what it does

A true-peak limiter is a brick-wall limiter that measures and limits the true peak of the signal, not just the sample peak. Most modern mastering limiters (Pro-L 2, Newfangled Elevate, Ozone Maximizer in true-peak mode) include a true-peak detection mode that catches inter-sample peaks and limits them.

When mastering hits the limiter for the final loudness push, the true-peak detection keeps the final master's true peak from going past the ceiling you set — typically -1.0 dBTP. The limiter does a little extra work to catch inter-sample peaks that a sample-peak limiter would miss.

In the master file, this means:

• Sample peaks might sit at -1.2 dBFS (lower than the true-peak ceiling)
• True peaks sit at -1.0 dBTP (right at the ceiling)
• Inter-sample peaks are caught and limited before they cause encoder clipping

What goes wrong without true peak limiting

A real example: a master at -8 LUFS integrated with sample peaks at -0.1 dBFS, no true peak limiting. The file looks fine on a sample-peak meter. The true peak meter reads +0.6 dBTP — already clipping in the lossless playback. On Spotify, the Ogg Vorbis encoder adds another 0.3 dB, putting the encoded file's peaks at +0.9 dBTP. Listeners hear distortion on every loud transient.

The fix is to remaster with the true peak ceiling at -1.0 dBTP. That costs about 1 dB of perceived loudness in the master, which Spotify's normalization would have taken away anyway. The result: clean playback across every streaming platform, no distortion on lossy encoding.

The short version

• Sample peak is what your DAW shows. It doesn't account for the reconstructed analog waveform.
• True peak (dBTP) is what the audio system outputs after reconstruction.
• Lossy streaming codecs can add inter-sample peaks on top of your true peaks.
• The right true-peak ceiling for streaming is -1.0 dBTP.
• Use a true-peak limiter on your mastering limiter chain.
• Verify your master's true peak with a true-peak meter before you ship.

A 1 dB difference between sample peak and true peak doesn't sound like much. After a lossy codec encodes the file and ships it to a phone speaker, that 1 dB is the difference between a clean transient and a distorted one.