Limiter and true peak

What it is and how it works

A limiter is a compressor with a very high ratio (∞:1 for a brickwall), very fast attack and lookahead: it keeps the signal from exceeding a ceiling and lets you raise the average level. In mastering it is the last processor and the one that determines loudness and the final peak. A modern limiter works in several stages: a fast one for transients, a slower one for the average level, with adaptive release.

True peak and inter-sample peak

Digital samples can all sit below 0 dBFS, but the waveform reconstructed by the D/A converter between one sample and the next can exceed them: these are inter-sample peaks. They get amplified after lossy encoding (AAC, Ogg, MP3), which changes the waveform's shape. A true peak meter (dBTP) oversamples (4× or more, as required by ITU-R BS.1770) to estimate these peaks; a true peak limiter prevents them. With FabFilter Pro-L 2, 4× oversampling and a minimum of 0.1 ms of lookahead keep inter-sample peaks within about 0.1 dB; True Peak mode adds about 5 ms of latency.

Parameters one by one

• Input / Gain: how hard you push into the limiter (= how much loudness you gain). In Fruity Limiter (LIMIT tab) it is GAIN.
• Ceiling / Output: output ceiling. Streaming: −1 dBTP; for masters louder than −14 LUFS Spotify recommends −2 dBTP. In Fruity Limiter it is CEIL (at maximum, +12 dB, limiting is disabled).
• True Peak: on for the final master.
• Attack / Lookahead: 0.1–5 ms. More lookahead = more transparent on transients but more latency; in Fruity Limiter the limiter's ATT also sets the look-ahead (0 ms = no latency).
• Release: short (1–50 ms) = more loudness, more distortion; long (100–500 ms) = cleaner but pumps; auto/adaptive is usually the best. Fruity Limiter also has CURVE (1–8) for the attack/release shape and SUSTAIN (RMS averaging).
• Style / Character / Mode: Pro-L 2 has styles (Transparent, Punchy, Dynamic, Allround, Aggressive, Modern, Bus, Safe); Emphasis has Versatile, Loud, Transient, Steady modes and the Emphasis knob.
• Stereo link / Linking: 100% = stable image; lower values give more loudness but the image can shift. In Emphasis: Linking 0–100% and Mid/Side mode (which pushes harder: lower the input by 3–6 dB).
• Oversampling: 2–16×; reduces distortion and inter-sample peaks.
• Dither: some limiters include it: use it only on the final 16-bit export.
• Level matching / Delta / Bypass: for honest comparisons (Emphasis has RMS Level Matching and Delta).

Limiters in FL Studio

• Emphasis (multistage mastering limiter): clean reduction stage + clipping stage (Hardness 0–9) + brickwall and True Peak (EBU R 128, oversampling), DC Block, Instant Recovery, oversampling up to 16×, Level Matching, Delta and LUFS meters (momentary 0.4 s, short-term 3 s, integrated) with Range. It is the most complete stock choice for the master.
• Fruity Limiter: versatile limiter/compressor/gate, without declared true peak; great on tracks and buses, and on the master if followed by a true peak control.
• Maximus: multiband + Master band; the manual indicates it as the last effect on the Master for mastering.
• Third party: FabFilter Pro-L 2, iZotope Ozone Maximizer, Waves L2/L3, Tokyo Dawn Limiter 6 (free), LoudMax (free), Sonnox Oxford Limiter, DMG Limitless.

Loudness and peak targets

Details and social platforms in the "Loudness by platform" guide. Spotify also normalizes upward (leaving 1 dB for lossy encoding) and in Loud mode applies a limiter that kicks in at −1 dB with 5 ms attack and 100 ms decay.

How hard to push

• Limiter GR: 1–3 dB on the peaks for a clean master; 3–6 dB for loud genres (better if preceded by a clipper and saturation). Beyond 6 dB: crushed transients, distortion, pumping.
• Distribute the work: bus compression (1–2 dB) + clipper (1–2 dB) + limiter (1–3 dB) sound better than 8 dB of limiter alone.
• Typical loudness by genre (integrated, final master): trap/rage/EDM −8/−5 LUFS; pop, K-pop, rock −10/−7 LUFS; hip hop −10/−7 LUFS; R&B −11/−8 LUFS; jazz, acoustic −16/−12 LUFS; orchestral −20/−14 LUFS. These are commercial-practice values, not obligations: after normalization an over-squashed master sounds smaller than a dynamic one.

On tracks and buses

• Limiter on single tracks: to stop isolated peaks (a screaming vocal, a harder snare hit) before compression; 1–3 dB.
• On buses: protection and controlled loudness (drum bus, 808 bus).

Common mistakes

• Limiter as the only source of loudness: distortion and pumping.
• Ceiling at 0 dBFS without true peak: clipping after conversion to AAC/Ogg.
• Release too short on the master with strong bass: harmonic distortion on the bass.
• Judging the master at the loudest volume: use level matching.
• Limiter active on the premix sent to the mastering engineer: remove it (unless requested).

How to hear it

• Raise the gain until you hear the kick "flatten" or the bass distort, then back off by 1–2 dB.
• Use Delta: if you hear recognizable music, the limiter is working too hard.
• Compare the master at −8 and −11 LUFS at matched loudness (Level Matching): often the second sounds bigger after normalization.