It doesn't show up in FR, that's the point. The detail and separation sucks, theres no dynamics or stage. The only people I see call it good are the ones who are already biased based on the measurements and don't have much listening skill.

Fwiw, the noise floor isn't the only problem with the DAC. There's some weird clock drift or buffer issue that makes it literally pitch shift up and down every few seconds, and it's very much measurable (and audible if you play a tone)