No effect on my setup - Firefox 76.0 on Ubuntu 20.04.
It is obviously not picking up the sound channel. Same problem with other equaliser add-ons.

Ottimo, anche se la "manina" che modifica la frequenza non è precisa.

Doesn't work :v

When used, I find that I get browser-wide audio issues, for instance:
-One of my channels falling out completely in firefox
-Audio being significantly delayed

Works with my streaming service! Yay!

Good idea, but on Firefox 72 it only works on YouTube BUT with a bad side-effect: video speed control won't work!
Furthermore, it ONLY works on YouTube and NOT with Spotify or any other streaming sites.

dose not work.

отключает скорость воспроизведения в ютуб

Just a pity the Youtube speed control doesn't seem to work when this addon is enabled :(

Excellent! the only add on that really works. Good job.

chrome version works perfectly while Firefox version works only on Youtube but not on sites with embedded videos

bueno

Got addicted! So much that now looking it for MPC-HC

Simple to use and works well on my daily visited websites.

Doesn't work for streamable, imgur and several others...

Doesn't work in imdb.com trailers.