PRESS PLAY
Push the glass
LEARN THE LIMITER.
A limiter stops music getting louder than a ceiling you choose. Here is one you can play with.
- 1Press play. The glass is your music.
- 2Pick what is playing: kick, bass, drums, synths, in any mix.
- 3Push the music up, or drag the lid down. Watch the water, and the wave.
Tip: you can also drag the lid.
How dynamic it is: the pointer goes red and slides left as the limiter flattens the peaks.
Lowering it brings the lid down. Less room, so the limiter works harder, and it gets quieter.
Pushing feeds the limiter more level. It is like pouring more water in.
CHOPPED OFF THE TALLEST PEAK IN THE LAST HALF SECOND: -- dB
Both are set to sound the same loudness, so you can hear what is still moving. Picking one puts the lid back to the top.
A clipper chops the very tops of the tallest peaks off instantly; the limiter then turns the rest down smoothly. They go hand in hand: the clipper takes the sharp spikes, so the limiter has less to do and the music can be louder before it sounds squashed. The clipper is set once on the whole track, so switching instruments off does not move it.
How to read the wave
- White is what comes out of the limiter.
- Blue ghost is what went in.
- Orange is what the clipper chopped off the tops of the tallest peaks, before the limiter (only when the clipper is on).
- Red fill is how much the limiter turned the wave down to fit.
- Dark blue between the red and the white is the level match: the setting is turned down after the limiter so Gentle and Crushed sound equally loud.
- Dashed line is the threshold. The wave is held under it (the true peak, between samples, can poke a hair above).
- Red bars on top show how hard the limiter is pressing.
LOUDNESS
--LUFS
How loud it feels. A bigger number (closer to 0) is louder.
LUFS measures how loud something sounds to a person, not just how tall the wave is. Streaming and club tracks are mastered to a loudness you can measure in LUFS. The number is negative: -8 is louder than -16.
GAIN REDUCTION
--dB
How much the limiter is turning the music down.
When a peak is about to go over the threshold, the limiter turns the whole signal down for a moment. This number is the most it turned it down in the last half second. 0 means it did nothing. A big number means it is working hard.
CREST
--dB
The gap between the peaks and the average. Big is punchy and alive.
Crest factor is how far the loudest peaks stick out above the average level. Lots of limiting flattens the peaks, so the crest number goes down and the music sounds squashed. Watch it fall when you push.
TRUE PEAK
--dBFS
The highest the real wave gets. It should stay near or under the threshold.
Digital audio is a list of samples, but the wave between the samples can rise a little higher than any sample. True peak estimates that real highest point. It can sit slightly above the threshold, which is normal for a limiter that watches samples.
Not just for loud. A sound tool too.
This page shows a simple limiter: it holds the music under a ceiling so you can get it loud. Engineers also use a limiter to shape how the music feels. Those are more advanced techniques, and the same limiter gets set very differently depending on the music. Here are two of them.
Warmer and softer
Disco, soul, classic house
Lean on the limiter. A short attack grabs the peaks early, and a long release lets the level creep back slowly. The sharp edges of the drums round off and everything sits closer together: warm, soft, glued.
Try it here: push harder and watch the red work for longer.
Punchy and clean
Tech house, EDM
Keep the limiter as invisible as you can and let a clipper take the sharp tips instead. The drums keep their snap, the limiting stays transparent, and it is still loud.
Try it here: bring the clipper up to about 3.5 dB, and see how much less the limiter has to do.
These need attack and release controls, which this page does not have yet. Push, threshold and the clipper are the ones you can hear and see here, so you can get a feel for the idea but not the full technique.
Questions you might have
What is a limiter?
A limiter is a safety ceiling for loudness. You decide the highest level the music is allowed to reach. When a peak is about to go over, the limiter quietly turns everything down for a moment, so it stays under the ceiling without chopping anything off. (The real wave between the samples can still poke a hair above it: that is what the true peak meter shows.)
Why does the water move?
The water is the level of the music right now, so it jumps with every kick and falls back between them. Pushing feeds the limiter more level, like pouring in more water, so the water sits higher. When the water reaches the lid there is no room left, and that is exactly when the limiter has to turn the music down.
What is the red on the wave?
Red shows how much the limiter turned the wave down to keep it under the threshold. It does not chop the top off (that is what a clipper does): it turns the whole sound down for a moment, then lets it back up. A little red is normal. A lot of red means you are squashing it.
What is the clipper?
A clipper chops the very tops of the tallest peaks off instantly, like trimming the tips of a hedge. The limiter then turns the rest down smoothly. Engineers usually use both: a little clipping first (about 3.5 dB here) takes the sharpest spikes, so the limiter works less and the music keeps more of its movement. Too much clipping sounds harsh and crunchy. On the wave, the orange is what the clipper chopped off.
What do Gentle and Crushed do?
They are two push settings. Both are set to the same loudness, so the difference you hear is not volume. Crushed has flattened the peaks, so there is less movement left in the music.
Why can I move the threshold?
The threshold is the lid. Lowering it has the same effect as pushing harder: less room, more limiting. The difference is that lowering it also makes the music quieter, because the ceiling is lower.
The demo plays the film’s own music loop. Meters are measured from it.