I don't get the lower ratings. It does exactly what I wanted it to do. It can lower the volume of the tab I have Bandcamp running in while I watch a stream. First addon I've found that can do that.

the only one that works for me :) only (minuscule) downside is that I'm an English speaker and while it's possible to translate the settings page (very ez) some menus cannot be translated and are a bit vague.

Works for YouTube tabs;
but does not work for Firefox's Reader View - read aloud.
Also does not work for Speak Selected added to Firefox context menu.
Review added 2026-01-30 for Ubuntu 24.04.3 LTS ; snap info firefox = 147.0.2-1 latest/stable

Doesn't seem to remember volume per-site (even though it is saved in the settings) (also for some reason the settings display for me in German)