I created a set of frequency sweeps in CoolEdit and encoded them myself, thinking that I would do the same thing you are thinking of doing.
In the end, the frequency-sweep tracks didn't really help me. The test tracks don't sound like songs, and you want the empeg to sound good with songs. In order to get an EQ that sounds good across your entire music collection, you will have to spend some time listening to your collection and tweaking the EQs a bit.
What makes the Empeg different from, say, a CD player, is that it lets you shuffle everything mixed up. So songs from two albums that were produced completely differently, will play one right after the other. This makes the differences in album production techniques stick out like a sore thumb.
So you're going to have to find a balance between accepting the fact that different albums will sound different, and tweaking your EQ to get a good compromise across your entire music collection.
At least until we get a per-song EQ feature...
It's taken me a while, but I've got my EQ to where my whole collection sounds pretty good. You end up making some compromises, but it's do-able. You just have to take your time about it and make your changes in small increments. Live with each change for a while before moving on to the next change.
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Tony Fabris