We got tired of installing volume booster extensions that request access to every website or inject tracking scripts. So we built one that doesn't. Sound Booster amplifies audio up to 600%, includes a 5-band equalizer with presets, keyboard shortcuts, and a live peak meter — using only three permissions.
Minimal Permissions
This extension only uses activeTab, storage, and scripting. The audio processor only activates when you click the extension icon. No page content access, no network requests, no analytics.
What You'll Learn
1. Boosting Volume
Click the extension icon in your Chrome toolbar to open the popup. The workflow is three steps:
Play audio in any tab
Open YouTube, a podcast, Spotify Web, or any page with audio or video. The extension detects media elements automatically.
Click the extension icon
The popup opens showing the volume slider at 100%. The status bar shows how many media sources were detected on the page.
Drag past 100%
The percentage display turns cyan when boosting. A DynamicsCompressor prevents clipping at high volumes. The slider snaps to 100% when you're near it.
POPUP — VOLUME STATES
NORMAL
BOOSTED
MUTED
The percentage display changes color: white at normal volume, cyan when boosted, amber above 300%, and red when muted. The toolbar badge also updates to show the current boost level.
2. Using the Equalizer
Expand the "Equalizer" section in the popup. Five vertical sliders control frequency bands from -12dB to +12dB. Each uses a BiquadFilterNode with a Q of 1.4 for natural-sounding adjustments.
| Band | Frequency | Controls |
|---|---|---|
| 60Hz | Sub-bass | Rumble, kick drums, deep bass |
| 230Hz | Low-mids | Warmth, body, male vocals |
| 910Hz | Mids | Presence, speech clarity |
| 4kHz | Upper-mids | Detail, articulation, bite |
| 14kHz | Treble | Air, sparkle, cymbals |
EQUALIZER PANEL — BASS BOOST PRESET
Each slider shows its current dB value above it. A horizontal center line marks 0dB (no change). The audio chain processes in order: source → EQ bands → gain → compressor → analyser → speakers.
3. Presets
Seven built-in presets cover common listening scenarios. Select from the dropdown above the EQ sliders. The sliders update instantly to show the preset's values.
| Preset | 60Hz | 230Hz | 910Hz | 4kHz | 14kHz | Best For |
|---|---|---|---|---|---|---|
| Flat | 0 | 0 | 0 | 0 | 0 | No EQ applied |
| Bass Boost | +8 | +5 | 0 | 0 | 0 | Music, movies |
| Treble Boost | 0 | 0 | 0 | +5 | +8 | Clarity, detail |
| Music | +4 | +2 | 0 | +3 | +5 | General listening |
| Movie | +6 | +4 | +2 | +1 | +3 | Film, TV shows |
| Voice | -2 | 0 | +6 | +4 | -1 | Podcasts, calls |
| Bass Cut | -8 | -4 | 0 | 0 | 0 | Reduce rumble |
You can also save custom presets. Click the save icon next to the dropdown, enter a name, and your current EQ settings are stored locally. Custom presets appear in a "Saved" group and can be deleted anytime.
4. Keyboard Shortcuts
These shortcuts work globally — even when the popup is closed. They use Chrome's chrome.commands API.
| Shortcut | Action |
|---|---|
| Alt+Shift+Up | Volume up 10% |
| Alt+Shift+Down | Volume down 10% |
| Alt+Shift+M | Toggle mute |
Custom Shortcuts
You can remap these shortcuts in Chrome at chrome://extensions/shortcuts. Any key combination supported by Chrome is available.
5. Peak Meter
The horizontal bar below the volume percentage shows audio output level in real time. It polls the AnalyserNode every 60ms using getByteFrequencyData().
PEAK METER — LEVEL ZONES
If the meter stays in the red zone, consider lowering volume or reducing EQ gains. The built-in DynamicsCompressor handles most clipping, but backing off produces cleaner audio.
6. On/Off Toggle
The toggle switch in the popup header instantly bypasses all audio processing. When off, gain resets to 1.0 (native volume) and EQ flattens — but your settings are preserved. Toggle back on and everything restores instantly.
ON/OFF TOGGLE STATES
ON
Badge: "200"
OFF
Badge: "OFF"
7. Dark & Light Mode
Click the sun/moon icon in the header to toggle themes. The preference persists across popup opens. The Chrome toolbar icon also adapts to your system theme — dark icon on light toolbars, light icon on dark toolbars.
8. Why We Built This
Most volume booster extensions on the Chrome Web Store have broad host permissions, inject analytics, have bloated UIs, or lack an equalizer. We wanted one that's powerful, private, and polished.
Technical Details
- Built with vanilla TypeScript — no framework overhead
- Manifest V3 — Chrome's latest and most secure extension platform
- Audio chain: MediaElementSource → BiquadFilter ×5 → GainNode → DynamicsCompressor → Analyser
- MutationObserver captures dynamically added media elements (SPA support)
- esbuild for instant builds, minified IIFE output
- Total bundle size under 25KB
Try Sound Booster
Free, private, and lightweight. Three permissions. Volume boost, EQ, and presets in one popup.
Add to Chrome