Yeah, I don't get that statement (besides the marketing advantages for the newer product). Stereophiles review either. My time with the A2 was slight (basically ordered a pair for a friend, heard both side-by-side in store, called friend and had him ship back, ordered A5 for him... then pair for myself too), but if you can mentally remove the bass completely from the other areas, the rest of the sig may sound similar. I consider the A2s bass to be so overpowering and flabby it's hard to hear anything else. So difficult for me to answer, but it's not just greater definition, etc. Only other hint is every A2 owner I know tries to fix with ramp/vibration stands and no one I know who owns the A5 does. I thought the A5 was also better than the M-Audio Audiophile BX5, but they have different purposes and it depends a bit on part of the signature (top v. bottom) you focus on. The BX5 was much closer to the A5 than the A2.