Put any recording in a virtual space: a small room, a concert hall, a bright plate or a huge cathedral. Choose convolution or algorithmic reverb, shape the decay, pre-delay and tone while you listen, then download the result as WAV or MP3.
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Space
No IR loaded yet. A WAV of a real room, hall or plate works best.
Choose an audio file or play the demo to start.
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How to use the Add Reverb to Audio
Choose an audio file (MP3, WAV, M4A, OGG, FLAC or a video) or press Play the demo to try it with a dry test clip.
Pick a space such as Room, Hall, Plate or Cathedral. Each one sets a matching decay, pre-delay and tone.
Press Play preview and adjust Mix, Decay, Pre-delay, Damping, Low cut and Width while listening; tick Hear dry signal to compare.
Optionally switch the engine to Algorithmic, or load your own impulse response WAV for a real measured space.
Choose WAV or MP3 and press Apply reverb, then listen to the result and press Download.
Typical reverb settings by space
These starting points match the presets in the tool. Decay is the RT60 time: how long the reverb needs to fall by 60 dB after the sound stops.
Space
Decay (RT60)
Pre-delay
Good for
Small room
0.3 – 0.6 s
0 – 5 ms
Voice-overs, podcasts, drums that need a little air
Room
0.8 – 1.2 s
5 – 15 ms
Acoustic guitar, natural-sounding vocals
Chamber
1.3 – 1.8 s
10 – 20 ms
Warm vocals, strings, piano
Concert hall
1.8 – 3 s
20 – 40 ms
Orchestral music, ballads, pads
Plate
1.5 – 2.5 s
0 – 20 ms
Pop vocals and snare drums (bright, dense, no early echoes)
Church
3 – 5 s
30 – 50 ms
Choirs, organ, ambient guitar
Cathedral
5 – 10 s
40 – 80 ms
Drones, cinematic swells, sound design
How the reverb is made
Convolution engine. For each space the tool generates a stereo impulse response: a handful of early reflections (the first echoes from nearby walls, spread over the first 20 to 220 ms depending on room size) followed by a dense, decorrelated noise tail that decays exponentially, falling 60 dB over the chosen decay time. The tail also gets darker as it fades, because real rooms absorb high frequencies faster than low ones; the Damping slider controls how quickly that happens. Your audio is then convolved with this response by the browser's built-in ConvolverNode.
Algorithmic engine. The classic Schroeder/Freeverb design: eight parallel comb filters with low-pass filtering in their feedback loops, followed by four all-pass filters, slightly detuned between left and right for width. Each comb's feedback gain is set with g = 10−3·D / RT60, where D is the comb's delay, so the network decays by 60 dB in exactly the decay time you choose.
Your own impulse response. Load any recorded IR (a starter-pistol or sine-sweep measurement of a real hall, or an IR of a vintage plate or spring unit) and the tool convolves your audio with it directly.
Tips for a clean, professional reverb
Cut the lows on the reverb, not the dry signal. A low cut of 150 to 400 Hz on the wet signal stops bass and kick drums from turning into rumble.
Use pre-delay to keep words clear. 20 to 40 ms lets consonants arrive before the reverb starts, so vocals stay upfront even with a long tail.
Less mix is usually more. 10 to 25% wet sounds natural on a full song; 40% and above is an obvious effect.
Match decay to tempo for rhythmic material: at 120 BPM one beat is 0.5 s, so a 1 s or 2 s decay fades out on a beat boundary.
Export WAV when you will keep editing, and MP3 only for the final file you share.
Frequently asked questions
What is reverb?
Reverb (reverberation) is the dense wash of reflections you hear after a sound stops in a room, as it bounces off walls, floor and ceiling and slowly fades. Its length, brightness and the gap before it starts tell the ear how big and how hard the space is, which is why adding reverb makes a dry recording sound like it was made in a room, hall or church.
What is the difference between convolution and algorithmic reverb?
Convolution reverb multiplies your audio with an impulse response, a recording (or simulation) of how a space answers a single click, so it reproduces that space very realistically. Algorithmic reverb builds the echo from a network of delay lines with feedback, in the classic Schroeder and Freeverb design: it sounds smoother and more synthetic and its decay can be changed instantly. This tool offers both, plus your own impulse response files.
What do decay, pre-delay and mix mean?
Decay is the RT60 time, how long the reverb takes to fall by 60 dB (about 0.4 to 1 s for rooms, 1.8 to 3 s for concert halls, 4 to 8 s or more for large churches). Pre-delay is the gap between the dry sound and the start of the reverb; 10 to 40 ms keeps vocals clear. Mix sets the balance between the original (dry) signal and the reverb (wet).
How much reverb should I add to vocals?
For a natural vocal, start with a plate or hall around 1.5 to 2.5 s decay, 20 to 40 ms pre-delay and a mix of 15 to 25%, with some low cut (200 to 400 Hz) so the reverb does not muddy the voice. Podcasts and voice-overs usually need little or no reverb; a short room at 5 to 10% only adds a sense of space.
Can I use my own impulse response?
Yes. Choose the engine My impulse response and load an IR file in WAV, AIFF, MP3, OGG or FLAC format. Mono and stereo IRs work, and many free impulse responses of real halls, churches and vintage reverb units are available online under free licenses. The decay slider is disabled for custom IRs because the file defines the decay.
Why is the exported file longer than the original?
Reverb keeps ringing after the music stops. The export keeps that tail, adding the pre-delay plus up to about 1.2 times the decay time to the end of the file, so nothing is cut off abruptly.
Is my audio uploaded to a server?
No. The file is decoded and processed with the Web Audio API in your browser, and MP3 files are encoded with the LAME encoder in JavaScript, so the audio never leaves your device.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.