Slaphead
500+ Head-Fier
I used to do EQ adjustments with Foobar but it seems software-based EQ introduces noise. Foobar is still my primary music player but I do not enable EQ on it since I noticed a slight whistling noise on the low frequencies. Now I let the RME do all the EQ adjustments and run the output XLR out to the THX amp which let's it all go through clearly and clean.
The HD58X Jubilees are one of the best bargain Sennheisers IMO. How did you mod them?
Hate to break it to you, but the RME's EQ is, wait for it, software based. It might use a FPGA to perform the EQ, but it's still software based.
The quality of SW based EQ is not down to the fact that it's software, but down to the algorithm used. Most if not all music today and remastered older recordings have been EQ'd in the studio using software.