PSR, PLR and LRA Explained: How Dynamic Is Your Master?
LRA, PLR and PSR describe how dynamic a master is. LRA is the spread of short-term loudness across a track, PLR is true peak minus integrated loudness, and PSR is true peak minus short-term loudness over the last three seconds. Keep PSR above 8 LU in the loudest sections. BeamTracer's Loudness tab shows all three live, free.
Hi, I'm Trina with BeamTracer.com, and today it's the three dynamics numbers most meters bury: LRA, PLR and PSR.
Take two tracks, both measuring exactly −14 LUFS integrated. Play them back to back. One punches; the other lies there, loud and flat. The main number on the loudness meter — the one everyone argues about — is identical for both, which means the difference between them lives somewhere else entirely.
It lives in three readings most people skip past: LRA, PLR and PSR. They sound like alphabet soup and they're actually three simple subtractions — and one of them comes with the single most useful threshold in modern mastering.
What are LRA, PLR and PSR?
Three readings, three different questions about the same track — one about the arrangement, one about the whole programme's headroom, one about this very moment:
| What it is | Window | The question it answers | |
|---|---|---|---|
| LRA | Spread of short-term loudness | Whole session | Does the arrangement move — verses vs choruses? |
| PLR | True peak minus integrated | Whole track | How much headroom does the whole track keep? |
| PSR | True peak minus short-term | Last 3 seconds, live | How crushed is this moment? |
All three are in LU, and 1 LU = 1 dB, so the numbers mean exactly what they look like: a PLR of 10 says the peaks ride 10 dB above the average loudness.
What is PSR, and why does PSR 8 matter?
PSR is peak-to-short-term-loudness ratio: how far the peaks stand above the loudness of the last three seconds. Heavy limiting shaves the peaks down toward the average, so the harder a section is pushed, the smaller its PSR — it's a live crush detector, moment by moment.
And it comes with a genuinely useful rule of thumb from the engineer who coined the measurement, Ian Shepherd: don't go below PSR 8 in the loudest sections, in any genre. Below that, loud parts reliably start to sound crushed — flat, fatiguing, gray. Above it, you can be as loud as you like and keep the punch.
On the BeamTracer loudness meter the three readings live together on the DYNAMICS card, and PSR turns amber below 8 LU so the threshold watches itself. The DYNAMICS view takes the same idea further — the waveform trace glows green while PSR is healthy, amber as it approaches 8, red when the last few seconds read crushed. It's an is-it-squashed check you can read from across the room, while the track plays.
The DYNAMICS view live: the waveform stays green while PSR is healthy. Watch it during your loudest chorus — if it goes amber, the limiter is eating the punch.
Here's why PSR became the competitive number in the streaming era. Once every platform normalizes playback, all tracks arrive at roughly the same perceived loudness — the loudness war's weapon is confiscated at the door. What survives normalization is the shape of the sound: after two tracks are leveled to −14, the one with more peak headroom simply hits harder. Being louder bought nothing; keeping your transients bought punch.
What is PLR (peak-to-loudness ratio)?
PLR is true peak minus integrated loudness: the headroom of the entire programme, one number. A modern loud master might have a PLR of 6–8; a dynamic one 12–15.
PLR is also the number that quietly decides what happens when a platform wants to turn your quiet master up — the boost can't push your peaks past the ceiling, so high-PLR tracks hit the cap early. If that sentence is surprising, the Spotify post walks the arithmetic with real numbers.
What is LRA, and what is a good loudness range?
LRA is the spread of short-term loudness across the whole session, in LU, with the extremes discarded so a fade-out or one silence can't distort the answer. It answers a different question from the other two: PLR and PSR are about transients — the microdynamics of hits and peaks — while LRA is about the macro, whether the arrangement itself moves.
- A brickwalled pop master: 3–5 LU
- A dynamic album master: 6–10 LU
- A live set or film mix: 15 LU and up
None of those is a grade. A club track should have a low LRA — nobody wants a 15 LU dynamic journey at 2 a.m. What LRA tells you is whether the track you made matches the track you meant to make.
The RANGE view draws LRA rather than quoting it: every short-term reading becomes a dot spread around the integrated level, fit to the session so far, colored by whether the spread reads flat, moderate or clearly dynamic. The histogram under the HISTORY view tells the same story as a distribution — with dashed brackets marking exactly the range the LRA calculation keeps.
LRA lies for the first minute
LRA is a statistic over the whole measurement, and statistics need data — below about 60 seconds of programme, the standard itself says don't trust the reading. A good meter flags LRA as settling until then. If yours confidently reports an LRA ten seconds into a track, it's confidently wrong.
Is the loudness war over?
De-escalated, not over. Normalization removed the incentive — a −8 LUFS master gets turned down ~6 dB on every major platform, gaining nothing — but plenty of charting tracks are still mastered that hot anyway, out of habit or fear. And the evidence that louder masters perform better on streaming? There isn't any. At matched playback loudness, listener studies find no reliable preference for the more compressed version — the sources are collected in streaming loudness targets. "Louder = more streams" is folklore from an era whose mechanism no longer exists.
Which puts the choice back where it belongs: master as loud as the music wants, keep PSR above 8 in the loud parts, keep true peak under −1 dBTP, and let the platforms do the leveling they're going to do anyway.
How do you measure your master's dynamics?
Drop the master onto BeamTracer's Loudness tab and read LRA and PLR off the DYNAMICS card for the whole-track picture, then play the loudest section live and watch PSR — it turns amber below 8 LU. It runs in the browser, free, with nothing to install.
- Open the Loudness meter — free, in the browser, no account
- Drag your master onto the tab — the whole file is analyzed in seconds
- Read PLR and LRA from the DYNAMICS card for the full-track story
- Play the loudest chorus live and watch PSR — amber below 8 is your crush warning
- Switch the hero view to DYNAMICS or RANGE to see the same story drawn instead of quoted
Every reading is also a control signal
This being BeamTracer, every one of these values has a pulse icon next to it — click it and the reading becomes a modulation source for any visualizer control. PSR inverts beautifully into "crush" effects; short-term loudness makes a useful slow driver for changes in a visual.
Next
- LUFS in plain language — the rest of the meter, without a manual
- What Spotify actually does to your track — normalization, the boost cap, and the −14 myth
- Level a multi-person livestream in the browser — the same meter on live voices
- Make a music visualizer from the same MP3 — your track, but visible
Find out how dynamic your master really is — in your browser, free.
MEASURE YOUR MASTER →Three numbers, no mystery left. beamtracer.com — I'll see you in the next one.