Chrome extension

YouTube Reverb Extension

A YouTube reverb extension for Chrome that adds adjustable reverb, decay and tone to videos as they play. Free, runs in the tab, records nothing.

Reverb is the half of slowed + reverb that people underrate. Slowing a track changes its mood. Reverb changes where the track seems to be. The Slow & Reverb for YouTube extension gives you both, but this page is about the reverb side: what it does to the audio in a YouTube tab, how to set it for different kinds of listening, and why nothing you play is recorded or sent anywhere.

The extension runs in desktop Chrome and Chromium browsers and works on youtube.com and music.youtube.com. It is free and installs from the Chrome Web Store. If you also want to slow videos down, the slow down YouTube videos page covers that in detail. If you want reverb on your own files with an MP3 at the end, that is the add reverb to song tool in the web editor.

What reverb does to a YouTube video

Every recording you hear on YouTube was mixed to sound close and present. Vocals are dry and forward, drums are tight, the whole thing is built for earbuds. Reverb undoes some of that on purpose. The extension takes the audio coming out of the video element, runs a copy of it through a convolution reverb, and blends that copy back in with the original.

Two controls shape the result. Reverb is the wet mix, from 0 to 100 percent, which sets how much of the reverberated copy you hear. Space is the decay time, which sets how long the tail rings after each sound. Short Space with high Reverb sounds like a tiled room. Long Space with low Reverb sounds like a hall heard from the back. The reverb control and space decay pages explain the pair in depth, and the same logic applies in the extension.

The video keeps playing normally. Reverb does not change timing, so you can leave speed at 1.00x and add only the room if that is what you want.

Listening use cases

Studying and working

Dry music pulls attention toward the lyrics. A moderate reverb pushes the vocal back and smooths the transients, so the music turns into a texture instead of a foreground. A playlist of pop or R&B at 0.90x with 35 percent reverb becomes background in a way the originals never are. Many people who use the extension for study never move the speed slider at all and only use reverb.

Falling asleep

Here you want long decay and dark tone. Space at 4 seconds or more, Tone pulled down several dB, and Bass up a touch. The high frequencies that keep you alert are the first thing to go. Set a sleep timer in your operating system rather than relying on YouTube to stop, because autoplay will keep the effect running through whatever comes next.

Nostalgia listening

This is the one the whole style was built on. Songs from your teenage years, slowed slightly and placed in a large space, sound like you are remembering them instead of hearing them. The combination of a small pitch drop and a reverb tail is what does it. Start at 0.85x and 40 percent reverb and adjust until it feels right. There is no correct value; the right amount is the one that gives you the feeling.

Live performances and old uploads

Low quality uploads from the early days of YouTube often sound thin and harsh. A little reverb and a few dB of bass makes them listenable. Keep the speed at 1.00x so the performance stays as it was played.

Settings for each kind of listening

If words become hard to follow, lower Reverb before anything else. Decay is rarely the problem; mix level is. If the result sounds boomy on laptop speakers, lower Bass, because small speakers exaggerate the low shelf once reverb thickens the mids.

What is happening in the tab, technically

The extension injects a small script into YouTube pages. That script finds the video element, routes its audio through a Web Audio graph (speed and pitch, convolution reverb, bass and tone shelves, stereo width), and sends the output to your speakers. Everything in that graph runs on your machine, inside the tab. No audio leaves the browser.

The processing is live. There is no buffer being saved, no file being written, and no server receiving anything. When you close the tab, the audio graph is gone. The only thing that persists is your settings and presets, stored locally through Chrome's storage API so you do not have to set them again. The extension permissions page walks through exactly what the tabs and storage permissions cover and what the extension never does.

This also means the extension cannot give you a file. It changes playback, not content. If you want to keep a reverb version of something, you need the source audio and the web editor, which exports MP3.

Why reverb works so well on compressed audio

YouTube serves audio at modest bitrates, and the encoder throws away the quietest and highest details. That loss is most audible as a slightly brittle, flat top end. Reverb fills the space the encoder emptied with reflections derived from the signal itself, so the ear hears a richer sound without any detail being invented. A few dB of negative Tone hides what remains of the encoder's edge. This is why slowed + reverb uploads often sound better than their sources to casual listeners even though they contain less information. The extension lets you apply the same trick to anything you watch.

Limits worth knowing

• It is a Chrome and Chromium extension for desktop. No phones, no Safari. A Firefox add-on called Slowverb exists for the same purpose.
• It runs only on YouTube and YouTube Music domains, not on embeds elsewhere.
• Reverb costs CPU. On a very old laptop with many tabs open, lower the reverb mix if you hear dropouts.
• It does not isolate stems. Reverb goes on the whole mix, vocals and drums together, exactly as it does in the editor.
• It does not record or export. Ever.

Open the free editor: upload MP3, WAV, AAC, OGG or FLAC, adjust speed, reverb, bass, tone, width and space, then export MP3 or a ZIP of many tracks. Everything runs in your browser.