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Soft Clipper Vs Limiter: What Each Does To A Peak

A clipper changes the shape of the wave, a limiter turns the level down for a moment. That difference decides which to use, and why most chains use both.

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By Nolvra

Shape Versus Gain

A clipper and a limiter both stop a peak from going past a line, and they get compared as if they were two settings of the same tool. They are not. A clipper changes the shape of the waveform: anything above the line is cut off or bent over, sample by sample, with no memory of what came before. A limiter changes the gain: when a peak arrives it turns the whole signal down for a moment and then lets it come back up. One reshapes the wave, the other moves its level. Everything else about how they sound follows from that.

What Each One Does To The Sound

Because a clipper works on each sample on its own, it has no attack and no release. It reacts instantly and leaves everything under the line untouched, so the body of a kick or a snare keeps its full level while only the very tip is removed. The cost is harmonics. Cutting the top off a wave changes its shape, and a changed shape means new overtones. On a short transient they read as a little extra bite. On a long, loud note they read as distortion. A soft clipper rounds the corner where the cut begins, which spreads those harmonics more gently than a hard, flat cut.

A limiter keeps the shape of the wave and moves its level, which is why it stays cleaner on sustained material. The cost is movement. The gain has to come down and go back up, and if that happens fast enough to catch a drum hit, you can hear the level duck and recover around it. Set it slow and the hit gets through. That is the trade a limiter makes and a clipper does not.

Using Them Together

Clip The Tips First

Put the clipper before the limiter and let it take the sharpest few dB off the transients. Those tips are short, so the harmonics a clipper adds there are brief and mostly read as attack rather than as distortion. What reaches the limiter is denser and has fewer isolated spikes for it to react to.

Let The Limiter Hold The Line

With the spikes already gone, the limiter has less to do and can work gently. It catches what the clipper left, mostly the sustained loud passages where clipping would turn into audible grit.

Pick The Curve By The Edge You Want

In BRIM, HARD cuts flat at the clip level and is the brightest of the four curves. CLASSIC, PRO and RATIO round the entry as softness rises from 0 to 100 percent. Set the drive first, so the material actually reaches the curve, then choose by ear. The BRIM modes and softness article draws each curve.

Match The Level Before You Judge

A louder version always sounds better for a few seconds. PRO and RATIO lift everything under their knee as softness rises, so bring the output gain down until the levels match before you decide which curve wins.

Oversampling And The Peak You Did Not Expect

Clipping creates harmonics above the top of the audio band, and at the normal sample rate those fold back down as tones that were never in the music. Oversampling runs the clipper at a multiple of the sample rate and filters the result back down, so those harmonics are removed instead of folding. BRIM goes from x1 to x256, opens at x4, and can use a separate factor for renders.

There is a side effect worth knowing. The filter that brings the signal back down rebuilds part of the cut edge, so the output of an oversampled clipper can peak slightly above the clip level. On BRIM's own measurements that is about a tenth of a dB on a low sine and up to about 4 dB on dense drums. That is why the output meter, which shows true peak, matters more than the clip setting, and why a ceiling or a limiter after the clipper still has a job. The true peak targets streaming services ask for are in what -14 LUFS actually means.

Which One The Material Wants

  • Short, sharp transients such as kicks, snares and claps: a clipper, because it takes the tip without moving the body.
  • Sustained loud material such as pads, held vocals and an 808 tail: a limiter, because clipping a long note is audible distortion.
  • A drum bus that has to get louder without losing punch: a clipper first, then light limiting.
  • A master that has to hit a level: a clipper for the spikes, a limiter for the line, and the true peak read after both.
  • An 808 that needs more presence: compare clipping with saturation first, since the three ways to drive a bass differ in what they do to the peak.
  • Anything going to a lossy encoder: leave headroom below zero on the true peak, whichever tool you end on.

Clip With The Numbers In View

BRIM clips with four curves, oversamples from x1 to x256 and shows the dB it took off, the output peak and the true peak, so the cut is something you read rather than guess.

See BRIM

FAQ

What is the difference between a soft clipper and a limiter?

A soft clipper reshapes the waveform above a threshold, sample by sample, with a rounded corner and no attack or release. A limiter turns the gain down for a moment when a peak arrives and leaves the shape of the wave intact.

Should a clipper go before or after a limiter?

Usually before. The clipper takes the shortest, sharpest peaks off first, and the limiter then works gently on what is left.

Why does a clipper need oversampling?

Clipping creates harmonics above the audio band, and without oversampling they fold back down as tones that were not in the music. Oversampling removes them before the signal returns to the session's sample rate.

Can a clipper's output go above its clip level?

An oversampled one can, slightly, because the filter that returns the signal to the session rate rebuilds part of the cut edge. Read the true peak on the output, and use a ceiling or a limiter if the level must never be passed.

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