Very late to the party but hopefully this thread is still relevant.
A couple of naive generic EQ questions first if I may. What are you looking to achieve with EQ, it is mostly to fix issues with frequency response (i.e. get closer to neutral), or is it to tune to preference?
Secondly, do you exclusively use computer audio? I'm guessing it's much less practical/more expensive to do otherwise, e.g with CDP analogue -> amp or CDP digital -> DAC/amp. It slightly puts me off that I could spend an awful lot of time tweaking a computer setup then have to take a step back with the CDP.
On the question of software, does anyone know of a good package that will work system-wide on linux (debian), i.e. not a plug-in for a particular player?
Somewhat more on-topic, the HD700. The OP seems to have made a significant improvement by improving neutrality (naturality?) I'm very interested in the changes needed here. I find it difficult to believe that Sennheiser did not attain their goal for the sound of this HP, especially given the $1000 launch.
Is this a case of technologically capable but badly tuned? Is it a case of the tuning being too niche, i.e. excels at something (which would be what) but at the expense of many other things? How did the standard signature come about? I've seen nothing from Sennheiser beyond vague statements of 'a more fun sound', whatever that means.
It may well be that for many the EQ isn't needed, I'm simply going off some of the large EQ parameter values in a small number of targeted areas and the cited improvement this has brought.
I have some thoughts on this but as I've rambled on enough, I'd be very interested to read everyone else's views.