Before buying the AKG K702 I initially looked towards the Denon AH-D340, that received high reviews for a low price (EUR 100). The cheap plastic (and too thin) cans kept me back from it. Also I couldn’t make it stay right upon my head. I didn’t have good device available in store to try it (only a provided ipod nano with bad mp3 recordings) however it sounded somewhat mudded compared a Philips Fidelio X1 (that was also priced more, EUR 250). I also listening to classical music through more standard (non portable) headphones, AKGK240MKII and 270, Grado, and notably an Audiotechnica ATH-AD500X that looked nice, fitted right and provided more full/open sound.
I ended buying the ATH (EUR 150). It sounded wonderfull on U2’s new album, as if I had jumped decades of audio technical innovation. The soundstage was amazing, each plane clearly distinct (on older tracks I also discovered previously non listenable whole instruments). The dynamic range was huge, somewhat too much (voice came front very stronger in chorus). Bass definition was impressive. However the guitars sounded recessed and not as nice as with my older AKG 240M (classic model). Also when playing Roland FP-7F piano mids and highs seemed to have disappeared, and strings samples lacked their appealing and motion. Finally the impedance was too low, leading to very limited range in level setting (was either too low or too high – unsuable through a computer audio output).
I then thought about high end AKG models, that also provide extended bass range (what I was looking to) compared to base K240. They were acclaimed for their mids and high signature, wich the K702 did (was availble priced EUR 209 – initially $400). In fact the emphasis on these frequencies is sometimes too high, leading to slight distorsion/clipping on some tracks (the lead guitar at the end of U2’s second track). Also there was some agressive lips sounds with womens singers. Overall the guitars and voice shine. What was unexpected is the impressive response in very low end, the drums kick is very present and detailed, the best experience ever (better than with the Audiotechnica, despite the later’s frequency range specification going as low as 5Hz – K702 low range limit is 10Hz). The upper bass however (typically bass sound) is however recessed compared to the Audiotechnica (that is less precise however covers a larger mid-low range).
Many state that the ALK needs long time (one or two hundreds of hours) to lower the harshness sounding in mid/high range and provide most dynamic in low end. In fact it depends much from music you listen. The K720 really shine on strong rock (3 Doors downs, U2) and metal, and also on Jazz/Ballad (really impressive Katie Melua and Katie Rose with these cans). The drums, guitars, voices and backed strings are amazing. Also the open design lead to impressive soundstage (listening to movies or playing games is also a great new experience with it). Be aware however that you will hear ambiant sounds as if you didn’t wear these cans (compared to the mid-closed AKG240).