Thanks for all the answers.
But from what I've heard changing cables smooths out this or tames that, basically really small changes that change the 'feel' of the headphone to something one would prefer more.
Now the HD800 is the first serious headphone I've ever bought (I had 'gaming' headsets before, neutral ones though) and I compared it to the T1 ,D7000 and HD650. I found D7000s way too bassy. The T1 and HD800 aren't that different but I prefered the more open and detailed sound that the HD800 had so I got the HD800.
Now I do enjoy listening to music (which doesn't happen that often) when I do but I don't have the experience to use vague terms like smoothing out treble and what not.
Perhaps I can find some way to test cables after I get a HDVD800 (or V200 and V800, depends on HDVD800's quality).