Mini sound test of my ATH-M50x using various devices:
PC on-board:
Sounds neutral and super flat to the point where everything sounds to be on the same level and it's quite disorienting to my ears because everything sounds claustrophobic.
PC + Creative Sound Blaster Audigy Fx
With the EQ I've put, sound now feels more wide and pronounced as well as with more clarity, every instrument has that bit more punch and vocals have a lot more body to them.
Samsung S8:
Pretty much sounds like my PC with the sound card, with slightly less bass.
This could all come down to placebo with me noticing that I'm using a sound card, but I really do hear that difference.
Video I used for this test: