I bought a few days, the Xonar Essence STX from Asus, because I assumed that it provides a much better sound quality than the Realtek chip ALC890B in my Asrock motherboard. But strangely, I had to find that it's the other way around. When I hear music with the Xonar, everything sounds as if one screws on Youtube the quality to 240p down. The ALC890 everything is crystal clear.
BTW I use the Sennheiser HD595 headphones.
What now? Was the sound card may be a bad buy?