Add Effects to an Audio File

An effects rack in your browser

Pick an audio file and chain up to five classic effects in a single ffmpeg pass — no upload, no account, everything runs locally in the browser tab. The stages are applied in the usual musical signal order:

1. Compression — evens out loud/quiet swings (none, light, medium, heavy). This is loudness dynamics, not file-size compression.
2. Chorus — detuned doubling for width and shimmer (none, light, deep).
3. Tremolo — a rhythmic amplitude wobble at 0.1–20 Hz (0 = off).
4. Echo — a single discrete repeat, 0–1000 ms delay (0 = off). 250 ms is a quarter-second slapback.
5. Reverb — a sense of space (none, room, hall, plate).

Any stage left at none or 0 is skipped, so you only pay for what you use. At least one stage has to be active — an all-off request is rejected instead of wasting a re-encode on an unchanged file.

Worked example

You have a dry vocal take, vocal.wav, that sounds flat and lifeless. Choose Compression → Medium to bring it forward, Chorus → Light for a touch of width, Echo → 250 ms for a slapback, and Reverb → Hall for space; leave Tremolo at 0. Keep the format on mp3 and you get back vocal-fx.mp3 with the whole chain baked in. Too washed-out? Drop reverb to room and echo to 0. Want a lo-fi pulse instead? Set Tremolo → 6 Hz and Reverb → Room.

What each stage does

• Compression — light for a gentle level-up, heavy to squash hard for a loud, upfront, "radio" sound. Heavier presets use a lower threshold, higher ratio and more make-up gain.
• Chorus — light is one gentle voice; deep is two detuned voices for a lush, wide shimmer. Great on thin synths, pads and backing vocals.
• Tremolo — a fixed 70% depth wobble; slow rates (2–4 Hz) pulse, faster rates (8–12 Hz) shimmer. Above ~20 Hz it stops sounding like tremolo.
• Echo — one clean repeat with a fixed decay. Short delays (80–150 ms) thicken; longer ones (300–500 ms) read as a distinct doubling.
• Reverb — room is tight and small, hall is big with a long tail, plate is bright and dense. It's a lightweight multi-tap approximation, so it runs the same everywhere without an impulse-response file.

Limits and edge cases

• Input files up to 10 MiB; any format ffmpeg can decode works.
• Echo delay is capped at 1000 ms and tremolo at 20 Hz — beyond those the effects stop being musical and start adding artefacts.
• Tremolo can't run between 0 and 0.1 Hz (ffmpeg's tremolo rejects it); use 0 for off or 0.1 and up.
• Effects are additive and can push loud audio into clipping. If the result crackles, ease off compression make-up or lower the level first with audio-volume-adjust, then add effects.
• Output is re-encoded (mp3/ogg at 192 kbps; wav/flac lossless; m4a AAC), and any embedded album-art image stream is dropped.

FAQ