Thanks for the replies guys. So it sounds like you're telling me there won't be much noticeable improvement in audio quality going from a Xonar DG to a more expensive sound card. Do you instead recommend any kind of equalizer app or program to download and use?
The difference would be a subjective thing and a value thing. If you swapped the DG for a Sound Blaster Z or DSX, maybe you'd think it sounds better, (not everyone does), but even if you did, is it worth it? If you swapped the DG for a $75-$100 amp, yes, it would sound better, but even if it does, is it worth it? It's hard to say since that depends on you. I could live with using the DG every day. I can't say the same for the ALC892 onboard, (and even that isn't terrible, it's just worse). Diminishing returns starts kicking in pretty quick after the DG. Especially on headphones that aren't hard to drive.
The more expensive stuff will sound better. It will. But the DG is already pretty good. If you have the extra cash, go for it. But I wouldn't lose a lot of sleep over it if you don't. If you have newb ears, you might not notice much if any difference anyway. It can take a while to notice non-obvious differences, and then even longer to be sure you even prefer the difference. "The bass is a little tighter and technically better with this amp... hmm, but the bloatier bass with the cheap amp actually sounds more fun to me."
A bigger difference would be if you got a big soundstage, open-back headphone. I don't know if you'd prefer something like that to the M50, but I'm saying such a thing would be a bigger sound difference than swapping out the DG.
I have $200 headphones that make me happy 95% of the time. I have $30 headphones that make me happy 85% of the time. Diminishing returns.
For EQ, use the free Equalizer APO. Add Peter's GUI or similar to it if you want a good GUI.
VLC is bad anyways, don't use it
What's wrong with VLC? What's better?