Free Browser Extension

Slow, reverb & bass boost
while you listen.

Turn any song on YouTube, Spotify or SoundCloud into a slowed + reverb version in real-time. No downloads, no re-uploads — just drag the slider and feel it.

Add to Chrome — Free

Firefox

Edge

Free forever · No account · 100% local processing

click play button

slide it

Lofi Chill Beat

Live Interactive Demo

0:00 / 0:00 Original

⚠️

YouTube and Spotify have no built-in audio effects. Close the browser, switch devices, or want a specific vibe — you have to search for unreliable re-uploads. BetterCallSlow applies effects instantly on the original track.

How it works

Four steps to your perfect sound

From install to vibing in under a minute.

Install the extension

Add from Chrome Web Store, Firefox or Edge. No account needed.

Open your music

Play any song on YouTube, Spotify or SoundCloud natively.

Click the icon

The popup opens with Speed, Reverb and Bass sliders immediately available.

Drag & vibe

Move the sliders in real-time. Changes apply instantly without page reloads.

Tutorial

How to make any song slowed and reverb

❌ The Old Way

Historically, making a slowed and reverb track required downloading the MP3, opening expensive audio software like FL Studio or Audacity, manually stretching the tempo, adding a reverb plugin, and exporting the file. It took 15 minutes just to hear a single song differently.

✅ The BetterCallSlow Way

Now, you can make any song slow and reverb directly in your browser. Just install the BetterCallSlow extension, play any track on YouTube, Spotify, or SoundCloud, and drag the speed and reverb sliders. The audio is processed in real-time, completely free, with no downloads required.

Features

Everything you need to shape your sound

🐢

Speed Control

0.5x to 1.5x. Slow it down to 0.8x for the classic slowed vibe or speed it up.

🌊

Lush Reverb

Adds a spacious, dreamy room echo. From subtle shimmer to cathedral wash.

🔊

Bass Boost

Low-band EQ boost up to +10dB. Makes any track hit harder seamlessly.

⚡

One-Click Presets

Jump instantly to Slowed (0.8x + 40% reverb) or Nightcore (1.2x) vibes.

🎨

Platform Themes

Popup auto-themes to red on YouTube, green on Spotify, orange on SoundCloud.

🔒

100% Private

Audio is processed locally using the Web Audio API. Nothing is uploaded.

Privacy

All processing stays local.

Web Audio API

Effects are applied using your browser's native audio engine. No audio data leaves your device.

No Data Collection

Zero analytics, zero tracking. We read the audio stream, alter the frequency, and send it back to your speakers.

No Account Required

Install and use immediately. No email, no sign-up, no permissions beyond the active media tab.

Get started now

Your music, your way.

Install in 5 seconds. Transform any track instantly. Free, forever.