How Reverb and Echo Work and How to Add Room Acoustic Ambience
Reverb is what a space does to a sound. Clap once in a stairwell and you hear the clap, then thousands of reflections arriving from every surface, too closely spaced to count, fading as the energy is absorbed. Recording in a treated room removes almost all of that, which is why dry recordings can sound oddly small and lifeless. Reverb puts a space back. This is a convolution reverb, meaning it works by combining your audio with an impulse response: a recording of how a space responds to one instantaneous sound. Real convolution reverbs use impulses captured in actual halls and cathedrals. This one generates its impulse mathematically instead, as white noise whose amplitude falls away exponentially. That is the standard synthetic approach and it produces a smooth, dense, characterless tail. Characterless is not an insult here: it means no particular room's resonances are imposed on your material, which is often what you want when the goal is space rather than the sound of one specific building. The two sliders do different jobs and interact. Decay sets how fast the tail falls: the level drops by about 26 dB in the time you set, so a 2-second decay is quiet but audible at two seconds, and fully gone somewhat later. Room size does double duty, controlling both the length of the generated impulse and how loud the reverb sits against the dry sound, which is why turning it up feels like moving from a booth into a hall rather than just making the tail longer. The dry signal stays at a constant level throughout, so you are always adding to your original rather than replacing it. A left and right impulse are generated independently from separate noise, which is a small detail with a large effect: because the two tails are uncorrelated, the reverb spreads across the stereo field instead of sitting in a lump in the centre.
How to Use the Audio369 Online Audio Reverb & Echo (Step-by-Step)
Reverb adds space, it cannot remove space that is already there. Audio recorded in a live room will end up with both, which usually sounds like a mistake.
From 0.1 to 1.0. This sets the scale of the space and how prominent the effect is, so small values stay subtle even with a long decay.
Half a second to six. Under one second reads as a room, two to three as a hall, and past four as a deliberate effect rather than a place.
The impulse is generated, then the convolution runs offline across the whole file. Long decays mean a longer impulse and more work per sample.
Technical Architecture & Audio Engine Specifications
Choosing a setting for the space you want
| Sounds like | Room size | Decay |
|---|---|---|
| A vocal booth, barely there | ✓ 0.1 to 0.2 | 0.5 seconds |
| A living room | ✓ 0.3 | 0.8 to 1 second |
| A church or a hall | ✓ 0.6 to 0.7 | 2 to 3 seconds |
| A cathedral | ✓ 0.9 to 1.0 | 4 to 6 seconds |
| An effect rather than a place | ✓ 1.0 | 6 seconds, on short sounds |
Who Uses Audio369 Audio Reverb & Echo? (Practical Creative Workflows)
Giving a dry vocal somewhere to sit
A close-miked voice in a treated room can sound disconnected from everything around it. A short reverb puts the singer in the same space as the music.
Warming up a spoken recording
Narration recorded in a wardrobe full of coats is dry to the point of claustrophobia. A very small amount of room makes it sound recorded rather than sealed.
Creating atmosphere for audio drama
The same line with a short decay and then a long one places the character in a car and then in a cathedral, without moving a microphone.
Ambient and drone pieces
Long decays on sustained material blur individual notes into a single evolving texture, which is the entire point of the genre.
Making a sample sound like a place
A dry foley recording of a footstep becomes a footstep in a corridor, which is far easier than recording in the corridor.
Frequently Asked Questions (FAQ)
Can this remove reverb from a recording? +
No. Adding reverb and removing it are completely different problems, and removal is genuinely hard. Nothing here undoes the room your microphone was in.
Is this a real hall or a simulation? +
A simulation. It is true convolution, but the impulse response is generated as decaying noise rather than captured in a real building. The result is smooth and neutral rather than the sound of one particular room.
Why does turning up the room size make it louder as well as longer? +
Because that control sets both the length of the impulse and the level of the effect against the dry signal. It is designed to feel like moving into a bigger space, where you would hear proportionally more reflection.
Does the file get longer when I add reverb? +
No. The audio keeps its original length, so a tail at the very end is cut off with it. Leave a moment of silence at the end of your file if you want the last note to ring out fully.
Should I add reverb before or after compression? +
Usually after. Compressing reverb pulls the tail up during quiet moments and makes the space breathe unnaturally, which is a distinctive effect but rarely the one you were after.
What is the difference between reverb and echo? +
Echo consists of discrete, delayed repetitions of the sound that you hear as distinct repeats. Reverb is a dense cluster of thousands of rapid acoustic reflections that blend into a continuous sense of space.
How do I prevent vocals from sounding washed out when adding reverb? +
Keep the wet/dry mix balanced with the dry signal dominant (around 15% to 25% wet). This retains upfront vocal presence and lyrical clarity while surrounding the voice with a warm, natural room decay.
Can I add realistic hall acoustics to dry instruments like guitar or piano? +
Yes. Dry direct-injected (DI) guitar or electronic keyboards benefit immensely from a medium room or cathedral setting, which restores the natural acoustic resonance of a physical performance space.