For me, buzzing/whistling was because I had switched the ini files and hadn't cleared the old ones, which persist in the save file. When I cleared them, the buzzing almost completely went away. If you've ever changed your ini files, open the console and type "refini" without the quotes.
--edit--
On a new playthrough, I experienced whistling that wouldn't go away when I did the above. By process of elimination, I found it came from a particular setting in the mod "Display Tweaks settings for Frame Generation (CS or ENB)". The problem disappeared when I turned its setting "EnableVSync=false" off. I did this by turning the setting into a comment by typing ";;" before it so it reads ";;EnableVSync=false".