Numio / Decibel

Decibel by Numio app icon

Decibel by Numio

A simple volume booster. Make quiet videos, calls and speakers louder.

v1.0.0Android 8.0+GPL-3.0

What makes it different

No ads and no internet permission. One big button turns the boost on, and it uses Android’s own built-in loudness effect, so nothing is recorded or sent anywhere.

Features

  • One big on/off button, plus a Quick Settings tile
  • Volume and Boost sliders on one screen
  • Boost up to +12 dB, or up to +24 dB with “Higher boost” (behind a warning)
  • Keeps working in the background, with a notification to stop it
  • Works for all apps on most phones; falls back to per-app boost in music and video players that support audio effects

Loud sound can damage speakers and hearing. If you hear crackling, turn the boost down, and keep it low with headphones.

Download

Download APK Changelog Source code
Version
1.0.0
File
Decibel-v1.0.0.apk · 1.0 MB
Updated
14 Oct 2026
Requires
Android 8.0 or newer
SHA-256
672dc4b47d58593c8f1c207be77dff2c6b2117a097461b183585beafc4aff2ed
Signing cert
C4:EA:F9:A9:54:2B:70:D4:72:AF:B5:7D:75:67:25:95:22:07:01:15:59:4B:8D:2D:68:EE:87:3E:E1:A2:8B:A1

How to install

  1. Tap Download APK on your Android phone.
  2. Open the downloaded file. If Android asks, allow your browser to install unknown apps. This is normal for apps outside the Play Store.
  3. Tap Install.

Verify your download

Optional, for extra safety. Check that the file matches the SHA-256 shown above.

Mac or Linux:

shasum -a 256 Decibel-v1.0.0.apk

Windows (Command Prompt):

certutil -hashfile Decibel-v1.0.0.apk SHA256

The signing certificate fingerprint is the same for every Numio app. Updates signed with any other key are not from me.

Get updates with Obtainium

Obtainium is a free app that checks GitHub for new releases and tells you when an update is out.

  1. Install Obtainium.
  2. Tap Add App and paste this address:
    https://github.com/rag-creation/numio-decibel
  3. Tap Add. Obtainium installs the latest version and notifies you about new ones.

Permissions

✓ No internet permission.

The app can’t send or receive anything online. Here is every permission it asks for, and why.

MODIFY_AUDIO_SETTINGS

Lets the app apply Android’s built-in loudness effect to make sound louder.

FOREGROUND_SERVICE

Keeps the boost running while you use other apps, with a notification showing it’s on.

FOREGROUND_SERVICE_MEDIA_PLAYBACK

Tells Android that this background work is about sound, which newer Android versions require.

POST_NOTIFICATIONS

Shows that notification, with a button to stop the boost. Android asks you first.

REQUEST_IGNORE_BATTERY_OPTIMIZATIONS

Lets the app ask you to exclude it from battery saving, so the boost doesn’t switch off on its own. You choose; the app works either way.

The built app also contains one internal permission added by the AndroidX library. It only lets the app talk to itself.

Help and feedback

Report a bug or suggest a feature Changelog Source code info@getnumio.org