The HD700 is a horrible headphone, avoid it like the plague.
Don't be so sure about the HD800. Its slightly darker than the K701 and is an absolute beast to power. The K701 is an extremely underrated headphone. It seems like it gets kicked to the dirt simply because it's cheap relative to the other flagships. It does a lot of things right and very few wrong. You'll be hard pressed to find a headphone that's a complete, direct upgrade to it. In fact, the only headphone that comes to mind is the STAX SR-009.
While I agree with you that the K701 is an incredible headphone does not get enough respect around here, the HD800 (and the T1) is in whole different league. You have to own them to truly appreciate them...a quick audition in a noisy store or meet does not do them justice.
Judging by how incredibly close the HD800 and K/Q701 measure, I highly doubt this. The T1 is great if you can get a good pair (and deal with the 10kHz peak) but Beyer's QC is inexcusably lenient, making it very easy to get a bad pair. I've owned 3 DT1350s and they all sounded wildly different, and two of them sounded like utter **** compared to the good pair.
Regarding the Lovely Cube, if it is a Lehmann Black Cube clone, you definitely don't need an upgrade.
Edited by takato14 - 3/18/14 at 2:09pm