[Audio Issue] Firefox Causes Background App Volume Drop on Tab Focus — All Volumes at 100%, Issue Not Present in Portable
Issue Summary:
Whenever I focus a Firefox tab (… (funda kabanzi)
[Audio Issue] Firefox Causes Background App Volume Drop on Tab Focus — All Volumes at 100%, Issue Not Present in Portable
Issue Summary:
Whenever I focus a Firefox tab (even a blank or safe mode one), the audio volume of background applications (e.g., Spotify) drops or changes audibly. It’s not a ducking effect (as all ducking settings are disabled), and Windows volume mixer shows all apps still at 100%. The issue happens only while Firefox is focused — not minimized, not unfocused.
Reproduction Steps:
Play music using Spotify or another app.
Focus any Firefox window or tab.
Background audio becomes quieter or altered — then returns to normal once Firefox is unfocused. Specifically on focus it will change system volume to 58, then return to what it was previously when unfocused.
System Info:
OS: Windows 11 (fully updated)
Firefox Version: 128.0.2 (issue present since at least 127)
Audio Output: Realtek and NVIDIA High Definition Audio (same issue on both)
Spotify Version: Latest Windows Store version
Windows Sound Settings:
Communications tab: "Do nothing"
All app volumes: 100%
No enhancements or spatial effects enabled
Troubleshooting Already Tried (No Success):
Step Result
✅ Disabled audio ducking in Windows No effect
✅ Disabled audio enhancements No effect
✅ Ran Firefox in Troubleshoot Mode (Safe Mode) Issue persists
✅ Changed Firefox audio backend to winmm via about:config No improvement
✅ Fully reset Firefox profile (about:support → Refresh) Issue persists
✅ Verified with Process Explorer (audiodg.exe shows activity on tab focus) Confirms session change
✅ Ensured all apps in volume mixer show 100% No volume mismatch
✅ Rebooted and tested cleanly Still occurs
✅ Tested Firefox Portable (fresh instance) Issue does NOT occur (portable version behaves as expected)
Additional Notes:
The issue appears to be triggered by the main installed version of Firefox only.
A completely clean portable version does not cause the volume change, suggesting something related to the system-wide install, global config, or registry entries is affecting it.
Even without extensions, without playing any video/audio in Firefox, just focusing the window causes this volume behavior.
What I Plan to Try Next:
Fully uninstall Firefox (including deleting AppData and registry leftovers), then reinstall cleanly to see if that resolves it.
Possibly test Firefox ESR if needed.
Request for Help:
Has anyone experienced Firefox causing audio session or DSP changes on focus, especially with audiodg.exe activity?
Could there be a hidden system-level or registry config that ties Firefox to a shared exclusive audio session?
Any way to trace which audio sessions Firefox creates and how Windows handles them?
Let me know if you'd like logs, about:support data, Process Explorer thread captures, or a video of the issue. I’d appreciate any help from the community in narrowing this down.
Thanks!
—Justin