Brick-Wall Audio Limiter
Pick an audio file and a ceiling — peaks are limited in your browser, nothing is uploaded.
Brick-wall limit audio in your browser
Pick an audio file and set a ceiling in dBFS — no sample in the result is
allowed above it. Add input gain to drive the signal into the limiter when
you also want it louder, and shape how the limiter reacts with attack and
release. The tool runs ffmpeg's alimiter lookahead limiter entirely in
your browser, so the audio never leaves your device — safe for unreleased
mixes, client work and private recordings.
A limiter is the standard last step before export: it guarantees a hard peak ceiling, so the file can't clip in a player, on upload, or after conversion to a lossy format.
Worked example
You have a finished mix master.wav that peaks right at 0 dBFS and distorts on
some players. Upload it, leave Ceiling at -1, leave Input gain at 0,
Attack at 5 and Release at 50, and choose wav as the output. The
result master-limited.wav sounds the same but its loudest peak now sits at
−1 dBFS, leaving the 1 dB of headroom that lossy encoders and streaming
platforms expect.
Want it louder too? Set Input gain to 6. The whole signal is pushed 6 dB
up before the ceiling, so quiet parts get 6 dB louder while peaks stay pinned
at −1 dBFS.
What each control does
- Ceiling (dBFS, −24…0) — the brick wall.
-1is the usual safety margin,-0.3squeezes out the last bit of level,-3leaves generous headroom for further processing. - Input gain (dB, −20…20) — drive applied before the ceiling.
0only catches peaks that already exceed the ceiling;+3…+9makes the result audibly louder by pushing more of the signal into limiting. - Attack (ms, 0.1…80) — how fast a peak is clamped. Short (
1–5) is transparent on speech and percussive material; longer (20+) is smoother but lets more of the transient through. - Release (ms, 1…8000) — how fast gain recovers after a peak. Short
(
20–50) sounds loud and tight; long (200+) is smoother and less pumpy. - Smooth release — averages the release over recent gain reduction, which sounds calmer on dense, peaky material.
- Maximize back to full scale — after limiting, re-normalizes the signal up to 0 dBFS. That deliberately overrides your ceiling, so leave it off whenever the ceiling has to be honoured.
Starting points
- Safety limit before export — ceiling
-1, gain0, attack5, release50. Nothing changes except that peaks can no longer cross −1 dBFS. - Louder podcast / voice-over — ceiling
-1, gain6, attack5, release80. Fuller and more consistent without audible clamping on speech. - Transparent mastering catch — ceiling
-0.3, gain2, attack20, release250, smooth release on. Only the loudest moments are touched.
Limits and edge cases
- Input files up to 10 MiB; any format ffmpeg can decode works (mp3, wav, m4a, ogg, flac, and more).
- This limits sample peaks, not inter-sample (true) peaks. A
-1dBFS ceiling is the conventional margin that covers inter-sample overshoot after lossy encoding; pick-2if you need to be extra safe. - Choose wav or flac if the ceiling must hold exactly. mp3, ogg and m4a are lossy: decoding them back can overshoot the ceiling by a few tenths of a dB.
- A 0 dB ceiling with 0 dB gain and no maximizing does nothing and is rejected — lower the ceiling or add input gain.
- Output is re-encoded because the limiter rewrites the samples (mp3/ogg at 192 kbps; wav/flac lossless; m4a AAC). Embedded album art is dropped.
- Limiting is one-way. Heavy drive (large input gain into a low ceiling) flattens the dynamics and can pump audibly, so keep the original if it matters.
FAQ
What's the difference between a limiter, a compressor and normalizing?
A limiter sets a hard ceiling — nothing gets past it, and everything below it is left alone. A compressor works by ratio: it turns down everything above a threshold by a proportion, changing the overall dynamics. Normalizing doesn't change dynamics at all — it applies one constant gain so the file hits a target peak or loudness. Use the limiter last, as a safety net; use the compressor to even out a performance; use normalization to hit a target level.
What ceiling should I use?
-1 dBFS is the standard safety margin and a good default: it stops clipping in
players and leaves room for the overshoot that mp3/AAC encoding introduces. Go to
-0.3 when you want every last bit of level and the output stays lossless. Go to
-2 or -3 when the file will be re-encoded more than once, or when it'll be
processed further downstream.
Why isn't my audio any louder?
With Input gain at 0, the limiter only touches peaks that already exceed
the ceiling — quiet material passes straight through unchanged. Loudness comes
from the gain control: raise it to +3…+9 dB to push the signal into the
limiter. The peaks stay pinned at the ceiling while everything underneath gets
louder.
What do attack and release actually change?
Attack is how quickly the limiter clamps an incoming peak. A short attack
(1–5 ms) catches sharp transients — plosives, drum hits — almost invisibly;
a longer one (20+ ms) lets the initial snap through, which sounds more open but
allows brief overshoot before the wall takes hold. Release is how fast the
gain comes back afterwards: short (20–50 ms) is loud and tight, long (200+
ms) is smoother. If a fast release sounds like it's breathing, lengthen it or
turn on smooth release.
Does this handle true-peak (dBTP) limiting?
Not exactly. The limiter works on sample peaks, so the ceiling is enforced on the
decoded samples rather than on the reconstructed analogue waveform. In practice a
-1 dBFS ceiling is the conventional margin that keeps true peaks in check
through lossy encoding; if a platform requires a strict −1 dBTP, set the ceiling
to -1.5 or -2 for extra room.
Is my audio uploaded anywhere?
No. The page downloads an ffmpeg WebAssembly build once and then processes your file locally in the browser tab — the audio never leaves your device.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool audio-limiter 'url=https://example.com/input' 'ceiling=-1' 'gain=0' 'attack=5' 'release=50' 'smooth_release=true' 'auto_level=true' 'format=mp3'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/audio-limiter/?url=https://example.com/input&ceiling=-1&gain=0&attack=5&release=50&smooth_release=true&auto_level=true&format=mp3Machine-readable descriptor: tool.json — title + parameters JSON Schema for agents.