Originally Posted by dysthanasiac
Without EQ, my HD650/O2-ODAC combination is unbelievably shrill and features a sound stage that closely resembles a gelatinous blob, despite the notorious "warm" and "dark" reputations of both. That's just how my ears work. With EQ - which is free and doesn't do anything I don't want it to do - I can turn that unholy mess into audio nirvana. No peaks, no notches, perfect fidelity, brilliant separation. It means I hear my music instead of my headphones/amp.
Well I'm not sure the O2 is known for it's warmth. It's known for being totally flat, "sterile" and a bad match with the HD650.
With an amp like the Bottlehead Crack you don't need EQ for the HD650 to get soundstage and not being shrill.
This is exactly why EQ is so good and important if you have gear like the O2-HD650. I'm also confident you can get all that tube magic in the future with the use of DSP if you so choose. Maybe it's already exist and I'm just not aware.
Please share the EQ settings you are using. That is what this thread is for.