I can tell you this much, the audio for the MK3 has a better dynamic range than that of the MK2. As far as pure loudness, I don't think there is a marked change. The MK2 was already plenty loud as it was. By the way, the noise canceling continues to be excellent. The MK3 is definitely worth the buy if you care about the dynamic range enhancement. Otherwise, the MK2 is a wonderful headphone in its own right.