LUFS, true peak & dynamic range explained

Quick reference

Metric	Measures	Target or diagnostic?
Integrated LUFS	Average perceived loudness, whole track	Target (~−14 LUFS)
Short-term LUFS	Loudness over a 3 s window	Diagnostic
Momentary LUFS	Loudness over a 400 ms window	Diagnostic
Sample peak (dBFS)	Highest individual digital sample	Incomplete on its own
True peak (dBTP)	Real peak after reconstruction / codec	Target (≤ −1 dBTP; −2 Amazon)
LRA (LU)	Loudness variation across the track	Descriptive
DR	Crest-style peak-to-average gap	Diagnostic
PLR	True peak − integrated LUFS	Diagnostic
PSR	True peak − loudest short-term LUFS	Diagnostic

LUFS — perceived loudness

LUFS (Loudness Units relative to Full Scale) is the modern standard for measuring how loud something sounds, defined in ITU-R BS.1770 (current revision BS.1770-4). It applies K-weighting — a weighting curve (a high-pass filter plus a high-frequency shelf) that approximates how we perceive loudness, so it tracks perception far better than raw peak or RMS. You'll see it three ways:

• Integrated LUFS — one loudness figure for the whole track. This is what streaming platforms read to decide how much to turn you up or down.
• Short-term LUFS — loudness over a 3-second window, useful for spotting the loudest section.
• Momentary LUFS — a 400 ms window, for catching transients.

Lower (more negative) is quieter: −16 LUFS is quieter than −9 LUFS. For the specific numbers each platform targets, see streaming loudness targets.

Sample peak (dBFS) vs true peak (dBTP)

Sample peak (measured in dBFS) is simply the highest individual digital sample in the file. True peak (dBTP) reconstructs the continuous waveform between samples — the way a digital-to-analog converter or a lossy codec does — and reports the real maximum. Those inter-sample peaks routinely exceed the highest sample.

This is why a master can read exactly 0.0 dBFS yet clip once Spotify encodes it to Ogg Vorbis: the true peak was above 0 dBTP all along, and the codec exposes it. Keep true peak at or below −1 dBTP (−2 dBTP for Amazon Music, and for any Spotify master hotter than −14 LUFS). Soneam measures true peak with 4× oversampling, the minimum specified in ITU-R BS.1770.

LRA — loudness range

Loudness Range describes how much the loudness varies across a track — broadly, the spread between its quieter and louder passages, expressed in LU. (Technically it's derived from the statistical distribution of gated short-term loudness, not a simple max-minus-min, which is why brief silences don't skew it.) A ballad with big dynamic swells has a high LRA; a wall-of-sound master has a low one.

LRA is descriptive, not a target: use it to confirm the master matches the music's intent.

Dynamic range: DR, PLR and PSR

Three related figures describe how much life is left in the master.

• DR (dynamic range) — most often the TT / Pleasurize Music Foundation "DR" value (the figure behind the Dynamic Range Database), a crest-style measure of the gap between peaks and average level. Higher means more punch and space; aggressively limited masters trend low.
• PLR (peak-to-loudness ratio) — true peak minus integrated LUFS. A quick read on how much the whole master was pushed: a PLR around 8+ usually breathes, while 3–5 signals heavy limiting. The "right" range is genre-dependent.
• PSR (peak-to-short-term ratio) — true peak minus the loudest short-term LUFS, so it reflects dynamics in the densest section rather than averaged across the song. A loud master can show a healthy PLR overall yet a crushed PSR in the chorus.

None of these has a single "correct" value — they're diagnostic. They tell you whether the master's dynamics fit the genre, and whether you've limited too hard chasing loudness the platforms will only give back.

Which numbers actually matter when you deliver

When you hand off a master, only two are hard targets:

1. Integrated LUFS — set it to the genre-appropriate level (≈ −14 LUFS for most modern releases; quieter for dynamic genres).
2. True peak (dBTP) — keep it at or below −1 dBTP (−2 for Amazon).

The rest — LRA, DR, PLR, PSR — are there to verify the first two were achieved without crushing the music. If your PLR or PSR has collapsed to hit a loudness number the platform is just going to turn down, you've traded dynamics for nothing.

A worked example: reading a real master

Numbers mean more together than apart. Here's a single pop master, straight off the meter, and what each figure is actually telling you:

Metric	Reading	What it says
Sample peak	0.0 dBFS	Looks maxed but safe — and it's lying to you (see the next row)
True peak	+0.6 dBTP	Already over full scale between samples; will clip when a codec re-encodes it
Integrated LUFS	−8.9 LUFS	Loud — Spotify Normal will turn it down ~5 dB to sit at −14
Loudest short-term	−6.1 LUFS	The chorus is the dense part driving that average
LRA	4 LU	Narrow range — consistent, intentionally so for the genre
PLR	9.5	Whole-track headroom is fine on paper…
PSR	6.7	…but the chorus is noticeably more crushed than the song average

Read top to bottom, the story is clear: the master looks clean on a sample meter, but the +0.6 dBTP true peak will distort after encoding, and the −8.9 LUFS loudness buys nothing — Spotify, YouTube, Tidal and Amazon all turn it back down to −14. The fix isn't more limiting. It's pulling the true-peak ceiling to −1 dBTP (here, hotter than −14 LUFS, so −2 dBTP is safer), and easing the chorus limiting that dragged PSR down — the loudness you'd lose is loudness the platforms were going to take anyway.

See your own numbers

The free Soneam loudness tool reports all of these — integrated LUFS, true peak, sample peak, LRA, DR, PLR and PSR — from a WAV or FLAC, and plays the master back the way each streaming platform will after normalization. Analysis runs in your browser; nothing is uploaded or stored.