Slowed & Reverb

Real-time speed, reverb, EQ, and stereo effects for YouTube™, YouTube Music™, and Spotify. Processing stays on your device.

Change how supported music and video sounds in real time. Open the toolbar popup and adjust the audio while it plays. The extension does not download media or send audio to the developer. Slowed & Reverb is free and open source under the MIT License. Every control is available from the start, with no account, ads, subscriptions, or locked features. Features - Speed from 0.5x to 1.5x, with tape-style pitch shifting or optional original-pitch preservation - Reverb, three-band EQ, echo, pan, stereo width, and saturation - Slowed + Reverb and Nightcore presets - Custom presets, optional keyboard shortcuts, and four popup themes - Per-tab settings that restore after navigation or reload Supported sites - YouTube™ - YouTube Music™ - Spotify web player Spotify support is optional. Access to open.spotify.com is requested only when you choose to enable it and can be revoked in browser extension settings. Other sites are left unchanged. Audio processing happens locally in the browser. Slowed & Reverb has no analytics, telemetry, advertising, remote code, or extension-originated network requests. Notes - A newly opened tab starts with effects off. - YouTube live streams support audio filters but not speed changes. Slowed & Reverb is independently developed and is not affiliated with, endorsed by, or sponsored by Google or Spotify. YouTube and YouTube Music are trademarks of Google LLC. Spotify is a trademark of Spotify AB.