I am getting that strange hissing sound, but i've found that it happens whenever i load a game up. It's definitely not any of my items, because i've switched them all out. the sixchange command works up until i load a game again. any advice?

Thats probably an enchanted object near by. It happens most often in your house if you have an enchanted item on display.

it happens no matter where i am. It's been going on for ages now. Pretty much since i got my nightingale gear.

I get that, but I think OP is getting a different problem.

Think you could record it?

Actually i get something similar; like a spell fizzing out or sometimes like a stone door closing. It never actually causes any problem as far as I know but I have been getting little bugs cropping up lately (some water flickering, microstutter etc, which are probably unrelated)

Yeah sounds like 10 spells being casted at once, almost like some really fizzy is fizzing down?