CPU usage high when task manager is closed

[ClubSpade12]

I have no idea what's going on with this, I use Windows 7 and have the CPU meter gadget on my desktop. My CPU usage hovers around 30% when I'm not doing anything, and my FPS in games dips. But, when I open up Task Manager, it goes down to below ten. I have no idea how this could possibly work unless the CPU meter is wrong when Task Manager isn't open but that doesn't make any sense. I've updated my drivers, I've restarted, I've done scans, I have no idea what could possibly be causing this.

i5-6600K
16gb RAM
GTX 1070
Windows 7 Ultimate x64

 

[ClubSpade12]

I actually managed to pinpoint the process, it's soundmixer. I did this by sorting the processes by highest CPU usage, and then opening task manager and quickly selecting the one at the top. After ending the process tree, I was able to close Task Manager and the CPU usage is normal. But I'm not sure why this process is all of the sudden screwing with my CPU...