Was the Blue Snowball in mode 1, and were your lips within 2 inches of it? The C920 has decent mic quality but, assuming you're using it for video, it needs to

Was the Blue Snowball in mode 1, and were your lips within 2 inches of it? The C920 has decent mic quality but, assuming you're using it for video, it needs to be some distance from your mouth, which affects audio quality.