3/6 using headphones and a high quality audio interface. Most of the time I was guessing. Honestly, I'm quite surprised I couldn't hear a clear difference between 128kbps and the other two. Either the mp3 codec has gotten a lot better, or my hearing has gotten worse (or maybe it was just placebo?), because I remember thinking 128kbps was complete shite, and almost all of my music is 256kbps VBR or higher now. Maybe this would've been a better test if they had a reference track for each (aka an ABX test)? Like, you could hear how it's SUPPOSED to sound, and then see which one of the three sounds the closest to the original. EDIT: Some people are claiming that the examples posted aren't very good, which may be the case, especially when it comes to the heavily produced pop tracks, but I felt like there was a lot of variety there.