Clipper vs limiter vs transient shaper

At a glance

What's the difference between a clipper, a limiter and a transient shaper?

All three work on the transient, the short spike at the start of a drum hit, and that's why they end up on the same drum bus and get mixed up so often. The difference is in what they're listening for.

A clipper and a limiter are ceiling tools. You set a level, the ceiling, and they stop anything going past it. The clipper does that by changing the shape of the wave at the moment it crosses the line; the limiter does it by turning the volume down around that moment. A sound that never reaches the ceiling goes through either of them untouched, apart from any gain you add on the way in.

A transient shaper has no ceiling and no threshold. It follows the level of the sound with two detectors, a fast one and a slow one. When the fast one jumps ahead, a hit has started, and the shaper turns that part up or down by the amount you set on its Attack control. When the fast one falls behind, the hit is dying away, and the Sustain control decides what happens to it. A quiet ghost note gets the same treatment as the loudest snare.

The lab boils this down to one number: how far the front of the loudest hit sits above its tail, measured as the peak at the front against the average level 40 to 100 ms later. On the drum loop it starts at 17.9 dB. Clippers and limiters can only shrink that gap, and a transient shaper can move it either way.

Reading the lab

The four buttons along the top switch between the original and the three tools; you can also press 1 to 4. The big screen shows the whole loop, with what goes in in pale grey and what comes out in colour. For the clipper and the limiter, "what goes in" means the loop after the Drive knob has turned it up, so the pink shading shows how much of it is trying to get past 0 dBFS.

The amber box marks the loudest hit, which the zoom underneath shows over 120 milliseconds. Next to it, the gain screen draws what all three tools do to that same hit: the one you're hearing is bright and the other two are faint, at their current settings. Match loudness is on by default, so switching between them changes the shape of the sound and leaves the volume alone.

Clipping a drum hit

A clipper leaves everything under the ceiling exactly as it is and cuts everything over it to a flat line. The Drive knob turns the loop up before it gets there, so more drive means more of each peak gets cut off. That's clipping, done on purpose and at a level you choose.

With 6 dB of drive on the drum loop, only 0.7% of the samples cross the line. The loudest loses 5.1 dB. Everything else, including the tail of every hit, comes out the full 6 dB louder, because the clipper only acts while a sample is over the line. That's why the gap between the front of the hit and its tail falls from 17.9 dB to 12.8 dB, and why the loop is 4.8 dB louder at the same peak level.

Clip the peaks in the lab

The cost is distortion. A flat top can only be built from extra high frequencies, so every cut adds harmonics. On a transient that lasts a couple of milliseconds you mostly hear the hit get a bit harder and brighter, and the gain screen shows why it stays short: the clipper's line only dips on the samples that are over, then snaps straight back. Soft clippers round the corner off instead of cutting it; soft clipping vs hard clipping vs limiting covers that difference.

Limiting a drum hit

A limiter never changes the shape of the wave. It watches the level and, when a peak is about to go over the ceiling, turns the whole sound down just enough to keep it under, then lets the volume back up over its release time. Most limiters use lookahead, a short delay that lets them see each peak coming and start turning down before it arrives. The one in the lab looks 5 ms ahead and releases over about 80 ms.

With the same 6 dB of drive, it turns the loop down by up to 5 dB. On the loudest hit the dip starts 5 ms before the peak and stays more than 1 dB deep for over 100 ms, which is longer than the front of the hit lasts. So the start of the tail, and any quiet hit that lands in that window, gets turned down with it. The front ends up 15.9 dB above the tail, and the loop is 3.0 dB louder at the same peak, less than the clipper managed.

Limit the same peaks

A limiter pushed too hard fails differently from a clipper: the quieter sounds sink every time a loud hit arrives and the loud hits lose their edge, which is pumping. Try it with the drive at 12 dB: the limiter turns the loop down by 11 dB and only makes it 4.3 dB louder at the same peak, while the clipper at the same drive makes it 8.7 dB louder. A limiter is a very fast compressor, and compression vs limiting explains where one ends and the other begins.

Shaping a drum hit with a transient shaper

A transient shaper has two controls, Attack and Sustain, both in decibels. Attack turns the front of every hit up or down and Sustain does the same to the part after it. Because it's following the shape of each hit and ignoring how loud it is, there's no threshold to set, and nothing stopping it from pushing the peaks over 0 dBFS.

Turn the attack up 6 dB and that's exactly what happens. The front of every hit comes up for about 26 ms, the peaks rise to +4.8 dBFS, and the front stands 23.6 dB above the tail. The loop is now 2.7 dB quieter at the same peak, because the peaks grew more than the average did. In a session that means you need something after it to catch the new peaks, which is where a clipper or a limiter comes back in.

Turn the attack up Turn it down instead

Turned down, the attack softens every hit without flattening anything. The front-to-tail gap drops to 12.2 dB, about where the clipper left it, but the loop gets no louder at the same peak: the peak falls 1.7 dB and the average falls almost as much. A transient shaper changes the feel of a hit; it isn't much use for loudness.

The sustain control is the move the other two can't make. At −6 dB the tail after each hit drops and the front stands 21.9 dB above it, so the drums sound tighter and drier. Boost it instead and the room and ring come up between the hits. Transient shaping goes through both controls in more detail.

Dry out the tails

Which one makes drums punch harder?

Punch is how hard the front of a hit lands compared with what comes after it, and how loud it is overall. Those two pull in opposite directions, which is why this question causes so much confusion. The table shows the lab's measurements for each setting on the drum loop.

If the drums sound soft and you want each hit to jump out more, the transient shaper is the tool. The clipper and the limiter both make the hits stand out less, even though the clipped version sounds bigger at first because it's louder.

If the drums already have plenty of snap and the track needs to be louder, a clipper gets you there with the least gain change, and a limiter catches whatever is left. Most of the time you want a bit of both, which is what the drum bus chain further down does. How to make drums hit harder covers the rest of the job, from choosing samples onwards.

Which one makes a track louder?

The clipper. On the drum loop it bought 4.8 dB at the same peak against the limiter's 3.0 dB, and the transient shaper's attack control bought nothing. Loudness at a fixed peak level depends on the crest factor, the gap between the peak and the average (RMS) level, and the clipper shrinks it the most because it only touches the few samples that are over.

The limiter has to turn down a whole stretch of sound around each peak, which costs some of the average as well. A transient shaper can shrink the crest factor too, by turning the sustain up, but on the drum loop +6 dB of sustain only bought 1.6 dB, and it fills the gaps with room sound as it goes.

When to use a clipper, a limiter or a transient shaper

Start with the transient shaper on individual drums, because it's the only one that changes the sound of the hit without needing it to be loud. A clipper is the usual way to win level on a drum bus. On a master the limiter goes last, always, since it's the one that holds every peak under the ceiling.

How to use all three on a drum bus

The order matters because each tool changes the peaks the next one sees. The shaper goes first because boosting the attack makes new peaks, and whatever comes after it is there to catch them.

1. Shape the hitsPut the transient shaper first. Set the attack and sustain by ear, with its output trimmed so it plays as loud active as bypassed. +3 to +6 dB of attack is plenty on most drum loops.
2. Catch the new peaksPut a clipper after it with its ceiling at 0 dBFS, or a little lower, and raise its input until it starts shaving the peaks the shaper made. Back off as soon as the snare starts to sound gritty. A limiter works here too if you'd rather keep more of the snap and give up some level.
3. Limit only at the very endOn a drum bus inside a mix, the clipper is often enough. On a master, the limiter goes last, with its ceiling at −1 dBTP and true peak detection on.
4. Compare at matched loudnessBypass the whole chain and match the levels before you decide it helped.

The lab plays one tool at a time, but its code can run two in a row. With the attack at +6 dB going into a clipper at 0 dBFS with no extra drive, about 0.2% of the samples get clipped. The front of the loudest hit ends up 18.8 dB above its tail, a little more than the original 17.9 dB, and the loop is 1.9 dB louder at the same peak. Swap the clipper for the limiter and the front stays 21.1 dB above the tail, but the loop is only 0.5 dB louder, because the limiter spent almost 5 dB of gain reduction undoing the boost. The drum bus lesson builds a whole chain around this.

Is a transient designer the same thing?

Yes. SPL's Transient Designer is a hardware unit whose two main controls are Attack and Sustain, and its name stuck to the whole category. Logic Pro's Enveloper, FL Studio's Transient Processor and the free Kilohearts Transient Shaper all do the same job. What makes something a transient shaper is that it reacts to the shape of each hit whatever its level.

Clippers and limiters have fewer naming problems. Most DAWs have a limiter built in, such as Ableton Live's Limiter and Logic's Adaptive Limiter. Dedicated clippers are less common as stock devices, though FL Studio has Fruity Soft Clipper and Ableton's Saturator has a Soft Clip switch.

Common mistakes

Forgetting the peaks a transient shaper adds

Six decibels of attack took the drum loop's loudest peak from −0.9 dBFS to +4.8 dBFS. If nothing after the shaper catches those peaks, they clip when you export, or they hit the limiter on your master almost 6 dB harder than before. Put a clipper or a limiter straight after any attack boost, or turn the shaper's output down.

Reaching for a limiter to add punch

A limiter can only take the front of a hit down. If a limited drum bus sounds punchier, it's because it's louder; match the levels and the original usually has more snap.

Long bass notes through a clipper

A clipper treats a held 50 Hz note the same as a 2 ms snare transient, so a sub that crosses the line gets flattened for its whole length and turns buzzy. Clip the drums on their own bus before they meet the bass. Limiting vs clipping has more on where each one fits.

Judging by volume

Clipping and limiting both make the loop louder at the same peak, and the louder version wins every quick comparison. Match the loudness, as the lab does by default, before you pick.

Hear how much louder the clipper is

A transient shaper on the full mix

A transient shaper reacts to every new note, so on a full mix the bass, the chords and the vocal consonants get the same treatment as the drums. If the drums need more snap, shape them before they reach the mix bus.

Train your ears

The quiz under the lab plays the drums through one of the three at matched loudness with the screens covered. Listen to the very front of each hit for grit, which means the clipper, and to the moment straight after it for the ducking that gives the limiter away. If the hits jump out more than they did, it's the transient shaper.

Questions people ask

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