Tuneslover
Headphoneus Supremus
I have a custom made balanced cable that I have been using with my HD660s that I pair with my Pioneer XDP-300R DAP. Compared to the HD660s, the HD58X is much easier to power and more lively. The HD660s are more subdued and allow some finer details but the HD58x is really a great pair of headphones for $150. Whereas the HD660s are sometimes a little too neutral for me I find the HD58x to have some pretty good bass extension and treble. I do feel like the treble on the HD58x is right on the edge of becoming tiresome. Maybe it will break in and become less of an issue. Time will tell, but I will be keeping these headphones for now...
As far as being specific about using a balanced cable. I think what you hear is pretty subjective. For me, it is affects the sound stage and the instrument separation. Sometimes it affects the soundstage in a way I don't like. But it really opens up the quiet spaces and the separation of instruments to my ear. The HD58X performs well with a balanced cable. To be honest, that is the only way I have used the HD58X, so I can't even compare to the stock unbalanced cable.
I have about 200 hours on my HD58X now. I swapped out cables (now using a SE stock HD650 cable) after about 100 hours on the HD58X. I have noticed that the high frequencies of these headphones have become more prominent which can become a bit fatiguing at times. Fortunately my Project Ember allows me to customize the sound to take the edge off the piercing high frequencies of some songs. Also I have noticed that the bass isn't as prominent as it was straight out of the box but again the Ember settings does assist in keeping things balanced.
As for using a balanced cable, I do have an XLR re-terminated stock HD650 cable but haven't tried it yet. I find the HD58X to be quite lively and louder than the 300 ohm HD650/6XX. Increases in volume ramp up quite rapidly so I'm not so sure that a balanced cable is going to bring too much positive to these headphones.