NAD C658 DAC Streamer is really a weak link but the DIRAC feature really helps with my room. I might have to get a stand-alone room correction device in order to update the streamer and Dac as the NAD does not allow you to disengage the DAC from what I understand.
I looked for some photos/measurements of your room to see if I could figure out why you needed room equalization, but no photos. I don’t know if I should ask you why you think that you need room equalization, or question myself as to why I think that I don’t need room equalization.