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darken edited this page Mar 3, 2026 · 4 revisions

Frequently Asked Questions (FAQ)

General Questions

Free vs Pro

The core functionality is free. A Pro version with additional features is available via in-app purchase on Google Play or sponsorship on GitHub.

Feature Free Pro
Volume Management
Number of Devices 2 Unlimited
Autoplay
Launch Apps
Volume Lock
Volume Rate Limiter
Connection Alert
Show Home Screen

Upgrading to Pro

  • Google Play: Buy the one-time in-app purchase or the yearly subscription. The subscription includes a free 14-day trial.
  • GitHub (FOSS Version): Tap the "Sponsor" button in the app to become a GitHub Sponsor. Sponsoring unlocks all Pro features.

Restoring Pro

  • Google Play: Sign in with the same Google account you originally purchased with. BVM will automatically detect your purchase.
  • GitHub (FOSS Version): Open the "Sponsor" button again and return to the app.

Common Misconceptions

Can BVM boost my volume beyond the phone's maximum?

No. BVM can only set volume levels within the range your phone already allows. It can't make your Bluetooth device louder than Android's maximum volume. No app can do this without root access. BVM's purpose is to remember and automatically restore your preferred volume levels per Bluetooth device — not to amplify beyond system limits.

If your Bluetooth device sounds too quiet at max volume, try toggling "Bluetooth absolute volume" in Android's Developer Options.

Can BVM play music on multiple Bluetooth devices at the same time?

No. BVM only manages volume levels — it doesn't control audio output or routing. Playing audio on multiple Bluetooth devices simultaneously (dual audio) is an Android/hardware feature. Some phones support this natively in their Bluetooth settings (e.g. Samsung's "Dual Audio"). Check your phone's Bluetooth settings to see if it's available.

Can BVM route audio (e.g. alarms) to a specific Bluetooth device?

No. BVM controls volume levels, not where audio is sent. Android decides which device plays alarms, calls, or media. For example, on Pixel phones, alarms always play through both the phone speaker and any connected Bluetooth device — BVM can't change that. Audio routing is handled entirely by Android.

Does BVM manage Bluetooth connections?

No. BVM doesn't connect, disconnect, or pair Bluetooth devices. It only reacts to connections that Android has already made and adjusts volumes accordingly. If your Bluetooth device isn't connecting automatically, that's an Android or device issue — not something BVM controls.

Troubleshooting

BVM isn't working at all

  1. Check that the app is enabled in Settings → Devices
  2. Ensure you've granted all required permissions
  3. Try disconnecting and reconnecting your Bluetooth device
  4. Check if battery optimization is preventing BVM from running

Volumes aren't being restored

  1. Make sure you've configured volumes for the device (tap device → toggle volume types)
  2. Check the reaction delay setting (default 4 seconds)
  3. Verify the device shows as "managed" in BVM
  4. Try enabling "Nudge Volume" for the device

The app keeps stopping/crashing

  1. Make sure you're on the latest version
  2. Try clearing app data and reconfiguring
  3. Check for conflicts with other Bluetooth apps
  4. Record a debug log and report the issue

Volume changes are too slow

Adjust the timing settings for your device:

  • Reaction Delay: Time before BVM acts (default 4s)
  • Adjustment Delay: Time between volume changes (default 250ms)
  • Lower these values for faster response

BVM stopped working after a phone or Android update

Android updates can reset permissions and re-enable battery optimization for apps. After updating, check the following:

  1. Re-grant all permissions BVM needs (Bluetooth, Notification access, etc.)
  2. Disable battery optimization for BVM (Settings → Apps → BVM → Battery → Unrestricted)
  3. Make sure the BVM foreground service is running
  4. Reconnect your Bluetooth device to trigger volume adjustment

If you've just updated to a brand-new Android version and the steps above don't help, please email support@darken.eu — there might be something that needs to be adapted for the new version.

BVM changed my volume when no Bluetooth device is connected

If you've added the phone's built-in "Speaker" as a managed device in BVM, its volume settings apply whenever no Bluetooth device is connected. This can unexpectedly change your alarm, media, or ringer volume. If you don't want BVM to manage your phone speaker's volume, remove "Speaker" from your managed devices list.

Autoplay causes skipping or fast-forwarding in some media apps

The Autoplay feature sends standard media button commands to start playback. Most apps handle this correctly, but some (like Pocket Casts) may interpret these commands as fast-forward or skip instead of play. This is due to how those apps handle media button events and isn't something BVM can easily work around. Try adjusting the "Autoplay Key Type" in device settings, or use a different player if the issue persists.

The app is using a lot of storage space

BVM should normally use very little storage. If you see unusually high storage usage (hundreds of MB or more), debug logs may have accumulated. To fix this:

  1. Go to your phone's Settings → Apps → Bluetooth Volume Manager → Storage
  2. Tap "Clear Cache"

If the problem persists after clearing cache, please email support@darken.eu with details so we can investigate.

Known Issues & Limitations

Android-Specific Limitations

  • Some Android versions prevent apps from showing the home screen
  • Volume UI might not show on some devices when BVM makes changes
  • Notification/ringtone volumes require special permissions on Android 7+

Device-Specific Issues

  • Some car stereos report as multiple devices
  • Hearing aids may have limited volume control
  • Some devices don't support separate notification volumes

General Limitations

  • Cannot control system-wide Bluetooth volume limit
  • Cannot bypass Android's absolute volume feature
  • Volume steps are determined by Android — BVM can't add finer steps between them. If the lowest step is still too loud, try toggling "Bluetooth absolute volume" in Developer Options.
  • May conflict with other Bluetooth management apps

Privacy & Security

Does BVM collect any data?

No. BVM is privacy-focused and doesn't collect, transmit, or sell any user data. It's also open-source so you can verify this yourself.