Guides

Slow & Reverb Extension Not Working? Troubleshooting Guide

2026-10-11

Fixes for the common problems with the Slow & Reverb for YouTube extension: no effect on the video, stuttering audio, the effect stuck on, YouTube Music tabs, conflicts with other audio extensions, and how to report a bug.

When the Slow & Reverb for YouTube extension is working, you forget it is there. When it is not, the symptoms are vague: the video sounds normal, or it stutters, or it stays slowed after you told it to stop. Most of these have the same handful of causes, and most of the causes are shared with every Chrome extension that touches a web page. This guide goes through them in the order you should try them, from the fix that solves the majority of cases to the ones you will rarely need.

Two notes before the list. First, the extension is version 0.2.1 at the time of writing and runs on desktop Chrome and Chromium browsers only. If you are on a phone, in Firefox or in Safari, it is not installed and nothing here applies; see the install guide for what runs where. Second, where we cannot verify a specific behaviour, the fixes below are the standard ones for any extension that modifies a page, which is what this one does. Nothing here will harm your browser. For what the extension is allowed to touch in the first place, read extension permissions.

Start here: the reload

Reload the YouTube tab. Press F5, or click the reload button, or close the tab and open the video again.

This fixes more reports than every other step combined. Extensions attach to a page when it loads. If the extension was installed, updated, re-enabled or had its site access changed while a YouTube tab was already open, that tab is running without the extension until it reloads. YouTube also navigates between videos without a full page load, and occasionally a long session leaves the player in a state the extension did not attach to. A reload resets everything.

If you have several YouTube or YouTube Music tabs open, reload each one, or close the ones you are not using. More than one tab with media playing is also the usual cause of stuttering, covered below.

Problem: no effect on the video

You open the popup, move the sliders, and the video sounds exactly as it did. Work down this list.

The embed point catches a lot of people. A YouTube video playing inside another website, a blog, a forum, a course platform, is served from YouTube but the page is not youtube.com, and the extension does not run there. Open the video on YouTube itself.

The On click setting is worth knowing about. Chrome lets you restrict any extension so it does nothing until you click its icon on a given page. If you or a previous setting put the extension in that mode, the controls will open but the audio will not be processed until you have clicked the icon on that specific tab. You can check this at chrome://extensions under Details and Site access.

Problem: the audio stutters or drops out

Stuttering means the processing is not keeping up. Convolution reverb is real work for a CPU, and a few things make it heavier.

• Too many media tabs. Every tab playing audio or video is competing for the same resources. Close the ones you are not using, especially other YouTube tabs.
• Reverb set high. A high wet mix with a long Space is the most expensive setting. Lower Reverb first, then shorten Space, and see if the dropouts stop.
• An old or busy machine. If the laptop is also compiling, rendering or running a game, audio processing in a browser tab is the first thing to suffer. There is no fix for that other than freeing the machine up.
• Hardware acceleration quirks. Occasionally, a browser's hardware acceleration setting interacts badly with audio processing on a particular graphics driver. If stutter persists after everything above, try toggling Use graphics acceleration when available in Chrome's system settings, restart the browser, and test again. Set it back if it makes no difference.
• Bluetooth headphones. Some Bluetooth stacks add their own buffering and can crackle under load independent of the extension. Test with wired headphones or speakers to rule this out.

A quick test of whether the extension is the cause at all: switch the effect off in the popup and listen. If the stutter continues with the effect off, the problem is elsewhere, usually the network connection or the machine.

Problem: the effect stays on after disabling

You switched the effect off, or picked Dry, and the video is still slowed or still has reverb.

First, check that YouTube's own playback speed menu is at Normal. The gear menu in the player has a speed setting that is independent of the extension. If you changed it at some point, the video will stay slowed no matter what the extension does. This is the most common explanation and it is not a bug in either tool.

Second, reload the tab. If the extension's state and the page's state have fallen out of step, the reload resynchronises them.

Third, if a reload does not clear it, disable the extension at chrome://extensions, reload the tab, confirm the video is normal, then re-enable and reload again. That proves whether the extension is involved. If the video is still slowed with the extension disabled, the cause is YouTube's menu or another extension.

Problem: works on YouTube but not YouTube Music, or the reverse

The extension runs on both youtube.com and music.youtube.com, but they are different pages with different players, and the two tabs do not share state in real time.

• Reload the YouTube Music tab. Same reason as always; if it was open before the install or an update, it has not attached.
• Check that site access at chrome://extensions includes both sites. If you restricted the extension to a specific site at some point, the other one will be excluded.
• If you are using YouTube Music as an installed app or progressive web app, launched from a shortcut rather than a browser tab, the extension may not run in that window. Open music.youtube.com in a normal tab.
• The popup shows the state of the tab you are looking at. If you adjust settings on a YouTube tab and then switch to a YouTube Music tab, the second tab picks up the saved settings on its next track or reload.

Problem: another extension is interfering

Several kinds of extension attach to the same video element the Slow & Reverb extension uses: volume boosters, equalisers, other speed controllers, audio enhancers, and some ad blockers that replace or wrap the player. Two extensions processing the same audio at once can cancel each other out, double an effect, or stop one of them attaching at all.

To find the culprit:

1. Go to chrome://extensions.
2. Disable every other extension that mentions audio, volume, speed, sound or YouTube in its name.
3. Reload the YouTube tab and test.
4. If the effect now works, re-enable the others one at a time, reloading and testing after each, until it breaks again.

Once you know which extension conflicts, you can either keep one of them disabled or set the conflicting one to On click so it only runs when you ask. Two speed controllers running at once is a particular problem, because both will try to set the playback rate and the result is unpredictable.

Problem: it stopped working after a Chrome update

Browser updates can leave extensions in an odd state. The usual sequence after a Chrome, Edge or Brave update:

1. Open chrome://extensions and check the extension is still enabled. Updates occasionally disable extensions that need re-approval.
2. If Chrome is showing a message that the extension needs new permissions, read it and accept if you are happy. The extension's permissions are tabs and storage; the changelog will say if that ever changes.
3. Reload all YouTube tabs.
4. If it still does nothing, remove the extension and reinstall it from the Chrome Web Store. Reinstalling clears its local storage, so you will lose saved presets. Write down any preset values you care about first.

Reinstalling is the nuclear option and is rarely needed, but it does rule out a corrupted install.

Problem: settings or presets did not save

Settings and presets are kept in Chrome's local extension storage through the storage permission. A few things can clear or block that.

• Reinstalling the extension deletes its storage.
• Clearing site data for extensions, or using a cleaning tool that wipes browser storage, can remove it.
• Incognito windows do not share storage with the normal profile, and extensions are not enabled in Incognito unless you allow them specifically.
• Each Chrome profile has its own extension storage. Settings saved in one profile do not appear in another.

If presets vanish regularly without any of the above, that is worth reporting.

Problem: ads are slowed too

This is not a fault. The extension cannot distinguish an ad from the video playing in the same player, so a pre-roll comes through at your speed and reverb. It is expected behaviour.

Problem: the picture is out of sync with the sound

The extension changes the playback rate of the video element, which keeps picture and sound together by design. If you are seeing drift, something else is likely slowing the audio independently, usually a second audio extension. Run the conflict check above. If it happens with every other extension disabled, report it with the video link.

How to report a bug

If you have reloaded, checked YouTube's own speed menu, ruled out conflicting extensions and the problem persists, write to contact@slowandreverb.com. A useful report includes:

The FAQ covers general questions about the extension and the web editor, and the changelog lists known fixes by version. Do not send audio recordings or screen captures with personal information in them; a video link and a description is all that is needed.

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.