I have a laptop from Acer and I also know how to make the normal louder and quieter. I played around a bit with the keyboard a few hours ago and somehow I came to Fn + K or L, and then there's on the screen as a quiet symbol as the key F9. And then I tried to make the normal louder again so Fn + F10 and that was then not louder.
Consult stored operating instructions or download operating instructions from the network.
On Windows, there's a speaker in the taskbar.
Make it louder again.
Without model, there's no precise information.