Rather than mess around trying all sorts of post-processing tricks on its "line" output signal to undo all the pre-processing that has been done inside the instrument to make its speakers sound good, why not try recording the digital as though it were an acoustic, i.e. with microphones?
Very good point, Rainer. I'd SOOOO much rather be playing music than messing around with software!
I actually tried once with the mics I have (cheap ones used for stage speeches/voice), and the result was horrible.
I started looking into which mics to buy, but along the way I also began learning [a little] more about increasing the quality of the audio with software. Truthfully, after getting a lot of good feedback and posting a handful of pieces here I was hoping I wouldn't have to mess with the learning and expense of switching to mic recording.
Right now I'm looking into perhaps borrowing some equipment from an acquaintance to see how it sounds and works with better mics.
Anyway, thanks for the suggestions!