Weak sound on Fujitsu laptop

[Karol 0]

I have an old Fujitsu Lifebook U Series and the music plays weak and a bit strange. i don't think it was always like that.
It has a Realtek High Definition Audio driver which looks O.K in Control Panel

[HarryTri 41]

First of all have a look at the sound settings, they may need some adjustment.

[Karol 0]

Settings seem O.K: all levels high

[siria 225]

I had the same prob on a notebook a few years back, sound was far too low (although "only" low, not "weird" at all).
Double-checked "all" settings, all looked fine. Triple-checked again... still no clue. What can this be???
Gave up...
Some days later hit accidentally a wrong F-key, and a volume bar flickered across the screen... OOPS!!
There are special hardware buttons for volume on the keyboard too! Had known this before of course too, but was so completely focussed on software settings, somehow completely forgot those hardware buttons.

[jumper 146]

...or dial on the side of the laptop.

Plug in headphones. Maybe the speakers are damaged.

 

[Karol 0]

On headphones the sound and volume are good and strong