Mozilla sound problem

[[YuMa]EMPEROR]

Hello there I couldn't find this specific problem anywhere on mozilla forums so I decided to give it a shot here , let me explain ;
When I listen to regular video/music on youtube or anywhere on the internet and I press ctrl key my sound goes on like 30% for 3-4 seconds then it gets back to 100% after that
Can someone help me to fix it
I have few screenshots

EDIT: happens ingame too not only mozilla

[kingW3]

Try this maybe it helps
Navigate to:
Control Panel -> Hardware and Sound -> Sound -> Audio properties -> Communications tab

Select Do Nothing from the dropdown box. Apply & OK.