Limiter

In-Depth Explanation

A limiter is an audio processor that prevents an audio signal from exceeding a defined ceiling level. It functions as a compressor with a ratio of infinity to one, meaning any signal that crosses the threshold is immediately reduced to that threshold level. Limiters are used primarily in mastering to raise overall loudness while preventing digital clipping.

How a Limiter Works

A limiter is a compressor with an infinite ratio. In standard compression, a ratio of 4:1 means that for every 4 dB the signal exceeds the threshold, only 1 dB passes through. A limiter takes this to the extreme: no matter how far the signal overshoots the threshold, the output never exceeds it. The threshold on a limiter is typically called the ceiling.

Key Parameters

1. Ceiling (or Output Ceiling): The maximum output level. Set to -1.0 dBTP (decibels true peak) for streaming masters to prevent inter-sample peaks during lossy encoding. Some engineers use -0.3 dBTP for club masters or -2.0 dBTP for especially loud material.

2. Threshold (or Input Gain): Lowering the threshold pulls the entire signal up against the ceiling. The more you lower it, the louder and denser the output becomes. Every 1 dB of threshold reduction equals 1 dB of loudness gain, but also 1 dB more gain reduction applied to the signal.

3. Attack: How quickly the limiter clamps down on transients. A true brick-wall limiter has an attack time of zero milliseconds. In practice, most limiters use look-ahead detection, analyzing the audio a few milliseconds in advance so they can react before a transient arrives. Look-ahead times of 1 to 5 ms are standard.

4. Release: How quickly the limiter stops reducing gain after the signal drops below the threshold. Short release times (50 to 150 ms) preserve loudness but can introduce distortion and pumping artifacts. Long release times (200 to 500 ms) sound more transparent but reduce the average loudness gain. Many modern limiters offer auto-release modes that adapt to the incoming signal.

Limiter vs. Compressor

The line between a compressor and a limiter is the ratio. A compressor with a ratio of 10:1 or higher is generally considered a limiter. A true brick-wall limiter has an infinite ratio and guarantees that no sample exceeds the ceiling. Standard compressors shape dynamics. Limiters maximize loudness. Most engineers use both in a mastering chain: compression first for glue and tone, limiting last for loudness.

Types of Limiters

• Brick-wall limiters: The most common type in digital mastering. Plugins like FabFilter Pro-L 3, iZotope Ozone Maximizer, and Waves L3 guarantee the output never exceeds the ceiling. Pro-L 3, released in 2025, added true peak limiting with 16x oversampling and up to 9.1.6 channel support for Dolby Atmos masters.
• Clip limiters: Instead of reducing gain smoothly, a clip limiter hard-clips the waveform at the ceiling. This preserves transient impact but introduces harmonic distortion. Popular for hip-hop and electronic masters where transient aggression matters more than transparency. Plugins like StandardCLIP and KClip are widely used.
• Multiband limiters: Split the signal into frequency bands and limit each independently. This prevents the bass from triggering gain reduction on the entire mix. iZotope Ozone Maximizer offers this with its IRC IV algorithm.

Real-World Example

You finish mixing a pop single. The stereo mix peaks at -3 dBFS with an integrated loudness of -18 LUFS. It sounds quiet compared to commercial releases.

You insert a brick-wall limiter on the master bus and set the ceiling to -1.0 dBTP. You lower the threshold by 7 dB. The limiter now applies up to 7 dB of gain reduction on the loudest peaks. The integrated loudness rises to approximately -11 LUFS. The track sounds dramatically louder and more competitive.

But there is a tradeoff. Those 7 dB of gain reduction flatten the transients. The snare drum, which previously cracked through the mix, now sounds squashed. The kick drum loses its punch. If you push the threshold down another 3 dB to reach -8 LUFS, the distortion becomes audible on bass notes and cymbal fades.

A skilled mastering engineer finds the sweet spot where the track is loud enough to compete but not so limited that it loses life. For streaming, -9 to -11 LUFS is a common target for pop and hip-hop. Spotify will turn it down to -14 LUFS, but the dense, limited character remains.

Why It Matters for Independent Artists

The limiter is the last processor in your mastering chain. It is also the easiest tool to misuse. Bedroom producers routinely push their limiter too hard, chasing maximum loudness. The result is a master that sounds flat, harsh, and fatiguing. Streaming platforms normalize loudness anyway, so an over-limited master at -7 LUFS gets turned down to -14 LUFS on Spotify, losing all the loudness advantage while keeping the sonic damage.

Three practical rules:

1. Set the ceiling first. Always set your output ceiling to -1.0 dBTP before touching the threshold. This ensures your master will not clip on any streaming platform. Use a true peak limiter, not a sample peak limiter, to catch inter-sample peaks. See our True Peak entry for why this matters.

2. Listen while you push. Lower the threshold slowly while listening on multiple playback systems. The moment you hear the snare lose crack or the bass start to distort, back off by 1 dB. That is your loudness ceiling for that track.

3. Use oversampling. Enable 4x or 8x oversampling on your limiter if your CPU can handle it. Oversampling gives the limiter a more accurate picture of the waveform between samples, reducing aliasing and inter-sample peak errors. FabFilter Pro-L 3 and iZotope Ozone Maximizer both offer this.

For genre-specific guidance, read our mastering for streaming platforms guide. To understand where limiting fits in the production chain, see our mixing vs. mastering breakdown. For stem-based workflows, our stem mastering article covers when to limit individual stems versus the stereo bus.

Related Terms

• Compression - The foundational dynamic processor that limiters build upon
• LUFS - The loudness unit that determines how streaming platforms turn your limited master up or down
• Mastering - The final production stage where limiters are applied
• True Peak - The measurement that determines where to set your limiter ceiling
• DAW (Digital Audio Workstation) - The software where limiter plugins operate