Some days I wish I could just find "the one" but sadly I like variety too muchI listened/compared the 400i,( 2.5 connectors) to my HD800, and HEK, and as a consequence, sold the HD800, and the HEK. Two basic thing convinced me, better Bass, deeper, cleaner, and the sound field, which is the deepest I have come across, but very good width, average height. Seems to suit me perfectly. I joined kickstarter to back other headphones, so we shall see, what happens. I am now looking for another pair of 400i, to keep as a spare.I imagine i am the only one ( Worldwide!.) to have done this, but my old ears have found what I have been looking for.
Have you tried one of the original ones with the SMC connectors and back plate? To me it was a bit better in the mids than the newer 2.5mm w/o back plate but my sample size was only 3 with 2.5mm and mine and another with SMC jacks so hardly a good sample size and both SMC jack ones were modded with grill and sorbothane.
@AthenaZephyrian, don't take this the wrong way but my GF was sitting with me looking at what I was reading and was a bit surprised to see a girl on Head-Fi, she also thinks you are pretty hot looking and quite knowledgeable about tinkering with the LD 1+ since she is still a noob with audio.