The last Plasma update added a sound feedback to each volume level when you use the Fn key + volume combination to change your system volume. 

This is a terrible change since this keyboard shortcut is often - if not always - used when you're already playing a song or a video. I personally use it when I'm watching a fullscreen film.

The icon displayed almost in the middle of the screen instead of a corner (like Windows 10) is already bad enough. Now, with this sound effect, it ruins completely the experience of watching videos fullscreen when you need to keep changing the volume levels for whatever reason.

Reproducible: Always