So I hear scratchy back round voice from my headphones when there is no audio playing. It's not too loud but still very annoying. I know it's not the headphones but in theory it could be the computer's headphone jack but I doubt that. I'm pretty sure it's the software I have updated everything normally and tried to mess with settings but can't get it to work properly. Also the quality of the sound doesn't suffer from this.

Guys?

Check your levels. You might have the mic enabled and boosted and otherwise routed to output, sometimes indirectly with channel bleed on devices that are not full duplex. Many internal audio devices have a notice-able noise floor. You wouldn't notice it on a train or plane, but in the quiet of a home it's fairly obvious. In a treated room like a recording studio it's painfully obvious. Various other things can make it come and go like system load. Or running cables past interference sources like most displays, or circuit breaker panels.

My first thought was what has been said above.

I would guess that the Mic is turned on and to a high volume level. Especially with pulseaudio, it can at times be overlooked if you are changing speakers or the microphone.

Does this also happen, if you disconnect the headphones, i.e. you hear the noise through the computers speakers well?