# Add Chorus to Audio Add a configurable chorus effect to an audio file in your browser with ffmpeg: voices, delay, depth, rate, decay, and output format controls. ## Run it - **CLI:** `gizza tool chorus 'url=https://example.com/input' 'voices=2' 'delay_ms=50' 'depth_ms=2' 'speed_hz=0.4' 'decay=0.4' 'format=mp3'` - **Web:** https://gizza.ai/tools/chorus/ - **Agents:** machine-readable descriptor (parameters JSON Schema) at https://gizza.ai/tools/chorus/tool.json ## Inputs - `audio` — Audio _(file; accept: audio/*)_ - `voices` — Voices _(field)_ - `delay_ms` — Delay (ms) _(field)_ - `depth_ms` — Depth (ms) _(field)_ - `speed_hz` — Rate (Hz) _(field)_ - `decay` — Voice level _(field)_ - `format` — Output format _(field)_ ## Output - Chorus audio (audio) ## Query parameters Open the tool pre-filled and auto-run via URL: - `voices` — Voices - `delay_ms` — Delay (ms) - `depth_ms` — Depth (ms) - `speed_hz` — Rate (Hz) - `decay` — Voice level - `format` — Output format - `url` — fetch the input file from a public URL (CORS-permitting) Example: `https://gizza.ai/tools/chorus/?url=https://example.com/input&voices=2&delay_ms=50&depth_ms=2&speed_hz=0.4&decay=0.4&format=mp3` --- ## Add chorus to audio in your browser A chorus effect thickens a sound by mixing the dry signal with short delayed copies whose delay time moves slightly. That tiny modulation makes a vocal, synth, guitar, or pad feel wider and richer than a single track. This tool wraps ffmpeg's chorus filter with friendly controls instead of raw filter text. Use **Voices** for how many delayed copies are added, **Delay** for the base delay time, **Depth** for how far the modulation moves, **Rate** for how fast it moves, and **Voice level** for the wet delayed copies. The page processes locally in your browser and exports mp3, wav, ogg, flac, or m4a. ## Worked example For a plain mono guitar part, start with the **Classic Chorus** preset: 2 voices, 50 ms delay, 2 ms depth, 0.4 Hz rate, and 0.4 voice level. For a wider synth pad, try **Lush Ensemble** with 4 voices, 55 ms delay, 5 ms depth, and a 0.55 voice level. For a moving shimmer, increase the rate above 2 Hz and keep the level moderate. ## Control guide - **Voices (2-4)**: more voices sound wider and denser. - **Delay (20-80 ms)**: shorter values stay tighter; longer values become spacious. - **Depth (1-8 ms)**: higher values make the pitch movement more obvious. - **Rate (0.1-5 Hz)**: low rates drift slowly; high rates shimmer or wobble. - **Voice level (0.1-0.9)**: higher values make the effect wetter and louder. ## Limits and edge cases - Input files are capped at 10 MiB. - Embedded album art or video streams are dropped from the output. - The dry gain and output gain are fixed to avoid clipping; use the voice-level control for effect amount. - ffmpeg's chorus filter has no feedback or separate dry/wet mix knob, so those are listed as out of scope. - Output is re-encoded; choose wav or flac when you need a lossless output container. ## FAQ
What is the difference between voices and decay? Voices controls how many delayed copies are mixed in. Decay controls the level of each copy. More voices make the sound wider; more decay makes those voices louder and more obvious.
Why do the voices not all use the same delay and rate? Each added voice is staggered by 8 ms and modulates at a slightly different rate. That deterministic spread prevents copies from lining up perfectly and collapsing back into one thin-sounding delay.
Can I use this on vocals and guitars? Yes. Subtle two-voice settings work well for vocals and clean guitars. Pads, synths, and ambient textures can tolerate more voices, depth, and decay.
Does this upload my audio? No. The page runs the ffmpeg WebAssembly runtime in your browser tab. Your audio stays local to the browser while the effect is rendered.
## 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. - [Fit Audio to an Exact Length](https://gizza.ai/tools/audio-fit-to-length/): Make any audio file an exact number of seconds — pad it with silence when it's short or trim it when it's long. Runs in your browser, nothing uploaded. - [Shorten Long Audio Pauses](https://gizza.ai/tools/audio-pause-shortener/): Tighten speech pacing by shortening long silent gaps to a natural pause length in your browser. Nothing is uploaded, free. - [Resample an Audio File](https://gizza.ai/tools/audio-resampler/): Change any audio file's sample rate — 8 kHz voice to 192 kHz studio — with high-quality ffmpeg resampling, right in your browser. 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.