LUFS, true peak & dynamic range explained

Quick reference

Metric	Measures	Target or diagnostic?
Integrated LUFS	Average perceived loudness, whole track	Reference (~−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	Spec ceiling (−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 expresses loudness measured using the algorithm in ITU-R BS.1770. The algorithm applies K-weighting and channel weighting to estimate program loudness. Meters commonly display three time scales:

• 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 following brief changes in loudness.

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 is the highest digital sample value, expressed in dBFS. True peak estimates the reconstructed signal’s maximum level between samples, expressed in dBTP. Encoding and decoding can change that maximum, so measure the decoded file to check a particular codec result.

A sample peak reading of 0 dBFS does not rule out inter-sample peaks above full scale. Lossy encoding can change the peaks further. Spotify recommends keeping true peak below −1 dBTP, or below −2 dBTP for masters louder than −14 LUFS. Check the decoded audio as well as the source. Soneam uses 4× oversampling for its true-peak measurement.

LRA: loudness range

Loudness Range describes how much the loudness varies across a track. Broadly, it's 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

These measurements compare peak level with an average or loudness measurement. They help describe dynamics, but do not determine sound quality.

• 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. A higher value indicates a larger measured peak-to-average gap.
• PLR (peak-to-loudness ratio). True peak minus integrated LUFS. A quick read on how much the whole master was pushed: higher values indicate a larger peak-to-loudness gap. 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. Compare it with PLR to see how the loudest passage differs from the track average.

Read these values alongside the material and your listening notes. A low ratio can result from the arrangement, the recording or processing; it does not by itself show that a master has been processed incorrectly.

Which numbers actually matter when you deliver

Check integrated loudness and true peak before delivery:

1. Integrated LUFS. Use it to understand the overall loudness and likely normalization gain. Choose the master’s level by listening and checking the delivery requirements.
2. True peak (dBTP). Check the destination’s true-peak recommendation and leave appropriate headroom. Measure a decoded test encode when you need to check peak changes.

LRA, DR, PLR and PSR provide further context about variation and peak-to-average relationships. Compare them with your references and listen to the passages where the readings differ.

A worked example: reading a real master

The following example shows how to read several measurements together:

Metric	Reading	What it says
Sample peak	0.0 dBFS	At full scale on the sample meter
True peak	+0.6 dBTP	Already over full scale between samples; whether that is audible depends on the codec and the material
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	Peak-to-loudness gap across the whole track
PSR	6.7	Smaller peak-to-loudness gap in the loudest passage

This example has a sample peak at full scale and an estimated true peak above it. The short-term loudness is higher than the integrated value, giving a lower PSR than PLR. Listen to the louder passages and test the intended codec before deciding whether any changes are needed.

See your own numbers

The Soneam loudness tool reports the measurements described here and offers loudness and codec previews. Audio is uploaded for server-side analysis; the original analysis upload is deleted after processing. Playback previews approximate the selected service and settings.

And when the numbers are where you want them, the next step is getting the client to hear the master properly and sign off on it: see how to send a master to a client for approval.

Frequently asked questions

What is LUFS, in plain terms?

LUFS measures how loud audio sounds to a listener over time using a K-weighting curve that approximates human hearing. It's defined in ITU-R BS.1770 and is what streaming platforms use to normalize playback.

What's the difference between dBFS and dBTP?

Sample peak in dBFS is the highest digital sample value. True peak in dBTP estimates the peak of the reconstructed waveform, which can exceed the sample peak. Lossy encoding can change both values; measure the decoded encode to check that change.

What is a good PLR or DR value?

There is no universal target. Compare the readings with the arrangement, genre and reference tracks. Lower peak-to-average ratios describe a denser signal, but do not establish whether the sound is better or worse.

What's the difference between PLR and PSR?

PLR subtracts integrated LUFS from true peak; PSR subtracts the loudest short-term LUFS. Comparing them shows how the peak-to-loudness gap differs between the whole track and its loudest short-term window.

Is LRA a target I should aim for?

No. LRA is descriptive; it tells you how much loudness varies across the track. Use it to confirm the master's dynamics match the music's intent, not as a number to hit.

Which metrics actually matter when delivering to streaming?

Integrated loudness helps estimate normalization gain. True peak helps assess headroom, including changes after encoding. The other measurements describe dynamics and variation; use them alongside listening.