The HE400i is my first serious pair of headphones, after dabbling with IEMs almost exclusively. I'm very happy with the purchase. It wasn't efficient enough driven straight from my AK100ii (sorry I even tried it), but out of my Cayin C5 amp with bass boost on, the good things about the 400i are very apparent. Smooth, nonfatiguing and neutral sound, with a warmish tilt, and magical mids. Could listen to it all day.
Driven out of my Centrance M8 the improvement is even more obvious. The treble was clear, transparent, detailed and smoooooth, magical mids made more lush, and the bass tight, deep, controlled, at just the right amount. A true jack of all trades, but I LOVE vocals with these. Soundstage was intimate, couldn't really fault them since I came from IEMs, and have yet to heard the likes of HD800 etc. Came from the RE400 which also had lush addictive mids but a very fragile cable that broke after a year. But by then I was addicted to the Hifiman house sound. Thought this would be a sidegrade... it's instead a huge step up!
So question, how much better can the HE560 and HE1000 be?