What Is a Limiter in Mixing and Mastering?

What Is a Limiter?

A limiter is a dynamics processor designed to stop a signal from rising past a chosen maximum level. Think of it as a hard ceiling: gain below that ceiling mostly passes; peaks that would break through get reduced so the output stays under the limit.

Producers meet limiters in two main contexts. On individual tracks or group buses, a limiter can catch occasional spikes (a snare hit, a vocal shout) without the long gain-reduction curve of a gentle compressor. On the master bus, a mastering limiter is the last safety net before export—raising overall level while preventing digital overs.

Limiters share DNA with compressors (threshold, attack, release, makeup gain), but they are tuned for extreme control. The practical difference is intent: a compressor shapes dynamics and tone over time; a limiter enforces a maximum peak so the file, converter, or stream encoder does not clip.

• Ceiling / output max The absolute highest level the limiter will allow on its output. On modern plugins this is often labeled Ceiling, Output, or Max Output, and is set in dBFS or dBTP.
• Threshold / input gain How hard you push into that ceiling. Many mastering limiters use input gain (or a linked threshold) so turning up the input creates more gain reduction and more loudness, while the ceiling stays fixed.
• Attack and release How fast peaks are caught and how quickly gain returns. Ultra-fast attack catches transients; slower release can sound smoother but risks pumping if overdone.
• Lookahead A short delay so the limiter can “see” a peak before it arrives and reduce gain in time. Essential for transparent brickwall behavior.

Brickwall Limiting: The Ceiling Concept

Brickwall limiting means the output is not allowed past the ceiling—full stop. The name comes from the idea of a wall at a fixed level: nothing gets over it. In digital audio that wall is usually just under 0 dBFS so sample peaks never hit full scale.

A brickwall limiter is not magic loudness. Pushing 6 dB into the ceiling can make a track feel “louder,” but it also flattens punch, distorts transients, and can make quiet sections feel denser in a fatiguing way. Streaming platforms then often turn that loud master back down, so you paid with dynamics and got little competitive benefit.

When brickwall is the right tool

Use brickwall behavior when you need a guaranteed maximum: final masters, safety on a live bus, or protecting a hardware converter. Skip heavy brickwall on every track; fix balance, EQ, and compression first so the limiter only does a few dB of peak control—not the whole mix job.

Limiter vs Compressor

Both tools reduce level when a signal crosses a threshold. The difference is how aggressively they do it and what you want to hear afterward. A compressor with a moderate ratio (for example 2:1–6:1) still lets some of the peak through; a limiter aims for near-infinite ratio so peaks stop at the ceiling.

Rule of thumb: if you want the part to feel more controlled and present, start with a compressor. If you need “this peak must never exceed X,” use a limiter (or a compressor followed by a light limiter). Many chains do both—compress for tone, limit for ceiling.

True Peak Limiting (dBTP)

Sample-peak meters only look at the highest digital sample. Between samples, the reconstructed analog (or the oversampled path inside a codec) can still go higher. Those inter-sample peaks are measured as true peak, usually in dBTP.

International recommendation ITU-R BS.1770 defines algorithms to measure programme loudness and true-peak audio level.^[1] A true peak limiter uses oversampling (or equivalent estimation) so the ceiling applies to that reconstructed peak, not only to the raw sample values.

Why care for streaming? Lossy encodings (Ogg/Vorbis, AAC, and similar) can create extra overs if the master sits hard at 0 dBFS. Spotify’s mastering guidance is explicit: keep true peak below −1 dB TP for lossy formats, and if the master is louder than −14 LUFS integrated, keep true peak below −2 dB to reduce encoding distortion risk.^[3]

Sample peak vs true peak in practice

If your limiter only shows sample peak at −0.1 dBFS but a true-peak meter hits +0.5 dBTP, codecs and some DACs can still clip. Enable true-peak mode on the limiter (or use a dedicated ISP/true-peak limiter), set ceiling to about −1.0 dBTP for streaming delivery, then re-check with a BS.1770-compliant meter.

Mix Bus Limiter vs Mastering Limiter

The same plugin type can serve different goals depending on where it sits. Mixing limiters protect and glue; mastering limiters finalize level and compliance.

If you will send the mix to a mastering engineer, leave headroom (commonly several dB under 0 dBFS, without a slammed brickwall on the mix bus). If you master yourself, treat the last limiter as a measured stage—not a volume knob you crank until the waveform looks like a sausage. For a full walkthrough of the mastering stage, see how to master a track and limiting for mastering.

Limiters, Loudness, and LUFS

A limiter controls peaks. LUFS (Loudness Units relative to Full Scale) measures perceived average loudness over time using the BS.1770 family of algorithms.^[1] You can hit a perfect true-peak ceiling and still be too quiet or too loud in LUFS terms—or crush the limiter and look “loud” on a peak meter while streaming still turns you down.

European broadcast practice codified loudness normalization in EBU R 128, which targets an average programme loudness of −23 LUFS and uses loudness range and maximum true peak descriptors.^[2] Music streaming is a different world: Spotify adjusts playback toward −14 dB LUFS (ITU 1770), with Premium modes at −11 and −19 LUFS, and publishes the true-peak tips above for masters.^[3]

Practical takeaway: set the limiter ceiling for delivery safety (true peak), then use gain staging and tasteful limiting to land where the music still breathes at a competitive integrated LUFS. Do not treat “as much limiter as possible” as a ranking strategy—platforms normalize loud tracks down. Deeper LUFS walkthrough: what is LUFS.

How to Use a Limiter (Clean Workflow)

This sequence keeps the limiter honest: mix first, measure second, limit last.

1. Fix the mix and gain staging
   Balance levels, EQ problem resonances, and control dynamics with compression where needed. Leave headroom so the master bus is not already slamming 0 dBFS. See gain staging if peaks are chaotic before any limiter.
2. Place the limiter last on the master
   After EQ, mild bus compression, and any saturation. Nothing after the limiter except a meter (or dither on final export if your DAW applies it at bounce).
3. Set a true-peak ceiling
   For streaming-oriented masters, start around −1.0 dBTP true peak, matching common lossy-delivery guidance such as Spotify’s −1 dB TP recommendation.^[3] Use true-peak mode if the plugin offers it.
4. Raise input (or lower threshold) in small steps
   Aim for a few dB of gain reduction on the loudest sections—not constant deep GR. A/B against the unlimited mix at matched loudness so you hear damage, not just “louder = better.”
5. Measure integrated LUFS and true peak
   Use a BS.1770-style loudness meter. Check integrated LUFS for the whole track, short-term peaks in drops/choruses, and max true peak. Adjust limiter input until the track is competitive without lifeless transients.
6. Export and re-check the bounced file
   Meters on the live master bus can disagree slightly with the rendered file. Open the bounce, re-measure true peak and integrated LUFS, then revise if encoding headroom is gone.

Free Metering and Mastering Tools

You do not need a boutique limiter to understand the concept. Many DAWs ship a stock limiter that can brickwall and, in newer versions, offer true-peak options. Pair any limiter with a dedicated loudness meter so you are not guessing from waveform height alone.

When you shop free plugins, prioritize: (1) a limiter with ceiling + true-peak or oversampling, (2) a LUFS / true-peak meter aligned with BS.1770 thinking, and (3) a simple spectrum or correlation meter so stereo width mistakes do not get locked under the ceiling. Stock tools plus one solid free meter will teach more than ten unmeasured preset chains.

If your next gap is compression technique rather than the final ceiling, continue with audio compression explained, best free compressor plugins, and mixing fundamentals.