I was on the verge of buying a Weiss 502 DAC for exactly that reason. It has DSP for room correction, or enhancement, built in so everything works in the digital domain before the analog conversion. EQ, De-esser, vinyl emulation, etc.
It's a brilliant piece of engineering and a phenomenal sounding DAC. But I just don't like the way DSP sounds. I agree it sounds "thin" and unnatural. It's ok on a subwoofer but not for my main speakers. So I changed my mind and stayed analog.
I have a White Instruments 1/3 octave equalizer between my preamp and amp. It's quiet, transparent and musical sounding. It allows fine tuning of specific frequency ranges. I use it primarily to reduce sibilance but also tweak a few other areas. It's a tool I have a lot of experience with but it's not brain science. A USB microphone, REW, and your ears are sufficient.