# Compress Audio Dynamic Range Even out loud and quiet parts of an audio file in your browser with threshold, ratio, attack, release and make-up gain. Local and private. ## Run it - **CLI:** `gizza tool audio-compressor 'url=https://example.com/input' 'threshold=-20' 'ratio=4' 'attack=20' 'release=250' 'makeup=0' 'format=mp3'` - **Web:** https://gizza.ai/tools/audio-compressor/ - **Agents:** machine-readable descriptor (parameters JSON Schema) at https://gizza.ai/tools/audio-compressor/tool.json ## Inputs - `audio` — Audio _(file; accept: audio/*)_ - `threshold` — Threshold (dB) _(field)_ - `ratio` — Ratio (:1) _(field)_ - `attack` — Attack (ms) _(field)_ - `release` — Release (ms) _(field)_ - `makeup` — Make-up gain (dB) _(field)_ - `format` — Output format _(field)_ ## Output - Compressed audio (audio) ## Query parameters Open the tool pre-filled and auto-run via URL: - `threshold` — Threshold (dB) - `ratio` — Ratio (:1) - `attack` — Attack (ms) - `release` — Release (ms) - `makeup` — Make-up gain (dB) - `format` — Output format - `url` — fetch the input file from a public URL (CORS-permitting) Example: `https://gizza.ai/tools/audio-compressor/?url=https://example.com/input&threshold=-20&ratio=4&attack=20&release=250&makeup=0&format=mp3` --- ## Compress audio dynamic range in your browser Pick an audio file and set the four classic compressor controls — **threshold**, **ratio**, **attack** and **release** — plus optional **make-up gain**. The tool runs ffmpeg's `acompressor` filter entirely in your browser to pull loud and quiet passages closer together, so the audio sits at a steadier, more consistent level. Nothing is uploaded, so it's safe for unreleased tracks and private recordings. This is **dynamics** compression (evening out the level), not **file-size** compression — to make a file smaller pick a lower bitrate with the audio-compress tool instead. ### Worked example A voice-over `narration.wav` where some lines jump out and others disappear: upload it, set **Threshold** to `-24`, **Ratio** to `4`, **Attack** to `10`, **Release** to `150` and **Make-up gain** to `6`. The result `narration-compressed.mp3` holds a tight, even level — the quiet lines come forward, the loud ones stop spiking, and the 6 dB make-up gain brings the whole thing back up to a comfortable volume. ### What each control does - **Threshold (dB, −60…0)** — the level where compression kicks in. Lower (−30) catches more of the signal; higher (−10) only tames the loudest peaks. - **Ratio (1…20)** — how hard everything above the threshold is squeezed. `2` is gentle, `4` is a firm even level, `10`+ approaches limiting. `1` is no compression. - **Attack (ms, 0.01…2000)** — how fast it clamps down once the signal passes the threshold. Fast (`5`) tames sharp transients; slow (`30`+) lets punch through. - **Release (ms, 0.01…9000)** — how fast it lets go once the signal drops back. Short (`60`) for speech, longer (`250`+) for smoother music. - **Make-up gain (dB, 0…24)** — level added *after* compression to restore the loudness the compressor pulled down. Try `3`–`6` when heavier settings leave the result too quiet. ### Starting points - **Voice / podcast** — threshold `-24`, ratio `4`, attack `10`, release `150`, make-up `4`–`6`. Even, forward, intelligible. - **Music glue** — threshold `-18`, ratio `2`–`3`, attack `30`, release `250`. Gentle cohesion without squashing the dynamics. - **Peak taming** — threshold `-10`, ratio `8`+, fast attack `5`, make-up `0`. Only the loudest moments get caught. ### Limits and edge cases - Input files up to 10 MiB; any format ffmpeg can decode works (mp3, wav, m4a, ogg, flac, and more). - A **ratio of 1 with 0 dB make-up gain does nothing** and is rejected — raise the ratio above 1 to compress, or add make-up gain to use the tool as a clean level boost. - Output is re-encoded because the compressor rewrites the samples (mp3/ogg at 192 kbps; wav/flac lossless; m4a AAC). Embedded album art is dropped. - Compression is a creative, one-way change — too much (very high ratio + heavy make-up) can sound flat and pumpy, so keep the original if it matters. ## FAQ
What's the difference between this and the "audio compress" tool? They do different things. This **audio compressor** does *dynamic-range* compression — it evens out the loud and quiet parts so the level stays steady, using threshold/ratio/attack/release. The separate **audio-compress** tool does *file-size* compression — it re-encodes at a lower bitrate to make the file smaller. Reach for this one to control loudness, and audio-compress to shrink a file.
What threshold and ratio should I start with? For speech and podcasts, threshold `-24` dB with ratio `4:1` gives a firm, even level; add `4`–`6` dB of make-up gain to bring it back up. For gentle "glue" on music, use a higher threshold (`-18`) and a lower ratio (`2`–`3`). To only catch the loudest peaks, raise the threshold toward `-10` and the ratio to `8`+.
Why does my compressed audio sound quieter? Compression turns the loud parts down, so the overall level often drops — that's what **make-up gain** is for. Add a few dB (start with `3`–`6`) to restore the loudness the compressor pulled down. With enough make-up gain the result can end up louder *and* more even than the original.
What do attack and release actually change? **Attack** is how quickly the compressor reacts once the signal crosses the threshold: a fast attack (`5` ms) clamps sharp transients like plosives or drum hits, while a slower one (`30`+ ms) lets that initial punch through before compressing. **Release** is how quickly it stops compressing afterwards: short releases (`60` ms) suit speech, longer ones (`250`+ ms) keep music smooth and avoid audible pumping.
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.
## Related tools - [Add Effects to an Audio File](https://gizza.ai/tools/audio-effects-rack/): Add reverb, echo, chorus, tremolo and compression to audio in your browser — chain effects in one pass and download MP3, WAV or more. No upload. - [Normalize Audio Loudness](https://gizza.ai/tools/audio-normalize/): Level any audio file to a standard loudness (LUFS) right in your browser — -14 for Spotify/YouTube, -16 for podcasts. Runs locally, nothing is uploaded, free. - [Convert AIFF to FLAC](https://gizza.ai/tools/aiff-to-flac/): Convert AIFF or AIF audio to lossless FLAC in your browser — preserve samples and textual tags, choose FLAC compression level 0-12, and download the result. - [Bleep or Mute Regions of an Audio File](https://gizza.ai/tools/audio-bleep-censor/): Censor an audio file in your browser — bleep, mute, or duck the exact time regions you pick. Set a tone frequency and output format. Nothing is uploaded, free. - [Audio Channel Tool](https://gizza.ai/tools/audio-channel/): Swap left/right channels, downmix stereo to mono, up-mix mono to stereo, or copy one side onto both — right in your browser. Nothing is uploaded, free.