Volume control?

How is the mixer even supposed to work? While the slider in the sandwich menu scales from “0%” to “100%” as expected, the mixer’s units are “dB” which means you can’t turn the sound completely off by dragging a slider to the bottom. What confuses me even more is that the numbers on the bottom contradict the numbers to the left of each slider:

mixer

For the screenshot, I left the left slider in the default position which is around -16 according to the scale beside it. But the number input field at the bottom contains the value 0,00dB. I moved the second slider to the top, that’s 0 dB according to the scale, but the number input field went to 24,00 dB. I moved the master slider to the bottom, which looks like it should be around -60, but the number input field says -24,23dB.

Looking closer at the scale, I also notice that the “-50” mark isn’t in the right place. Even though the scale is logarithmic, the -40 and -50 marks should be further apart.