The older AKG models are my favorites although I have not heard the K712 or K612. I used to own the K702, and K601 but ended up selling them when I got my K400 and later a K500 and K240DF. I only had a Crack at the time I owned the K400 and K500 and which it was a good match the SEX works better with these 120ohm headphones and I really like the sound and the massive soundstage of the K400. I'd recommend buying one off ebay if you can.