Speakers volume lower than it should be

I have powered speakers connected by USB to Fedora KDE 32 machine.

Bus 003 Device 002: ID 0d8c:0043 C-Media Electronics, Inc. TUK by Kanto

Until recently everything was fine, until I noticed that say at 50%
volume it plays quieter than before. It actually plays quieter at every
volume level, but at 18% it goes mute completely even though at 19% it’s
nowhere near the minimum.
Also if I use volume control on speakers or using the remote control,
I can’t go lower than 15% - it seems that speakers think that 15% is
the 0%.
Another thing - when I power off/power up speakers they start playing
significantly louder, and after couple seconds they lose decibels. I
would guess that when powered up they start playing at the level I’ve
used to them playing, but something kicks in and they go quieter.

Install pavucontrol
See whether the UI helps you balance things up


Not sure what I could do there. For example at 5, 10 or 15% master volume I do see blue line jumping, but no sound is coming out from the speakers.

It gave me an idea to plug in headphones to the speakers (there’s 3.5mm out), and I do hear sound playing even at 5%.

If I do the same experiment and turn off/turn on speakers headphones do start playing louder and after a second go quieter as well.