Sometimes it's there's no way to distinguish, because in some audio components, these qualities can seem mutually exclusive. ie, if they're highly resolving, they're also edgy, bright, and unnaturally sharp. Or if they're relaxed/euphonic sounding, they can't convey much detail & sound dark/murky. A lot of otherwise pretty decent audio gear is like this: binary, all one thing or all the other.
However, in some audio products--in my experience, the really good ones that are very well designed & "voiced" (tho not necessarily crazy $$), you can get both. You get a relaxed, musical sound with lots of detail. This is a sonic holy grail IMO: hard to find, but once you hear it, easy to recognize.
The ATC SCM12 Pro's (based on very short-duration listening in an alien environment w/bad cabling) might just be an example of this "you can have it all" phenomenon. For example, I put on symphonic music that has big dynamic peaks w/all instruments playing, also quieter passages w/just a few instruments. The quiet passages were clear as a bell, detailed, not bright. Then came the louder passages, and the ATCs scaled way up, instantly, to much louder, but still very clear, with all instruments blazing away. During these bigger/louder moments, the violins & other string sections didn't sound hard or edgy...they sounded exactly as the quieter passages did, tonally, just louder. It was easy to hear different instruments, also some rather subtle sonic cues like size of hall, reflections, and so on. In other words, lots of resolution w/o the price of peaky brightness.
I have a lot of listening to do when the ATCs land in home office. Maybe they'll stay this way or get even better; or they might go downhill because my office isn't an optimal environment. Then again, the environment they were in when I first heard them is way less optimal than the office.
An example of this "have it all" thing among headphones (in my experience) is the ZMF Eikon. Listening to that amazing closed design, I was wowed by the sheer detail & nuance available at every part of the frequency range...these are highly resolving headphones. Yet at the same time, they have a quality of subtle warm, relaxed/organic tonality, no punishing brightness (you can make them sound peaky, but it takes weird combinations of a certain SS amp + a certain music cut to do it).
Another headphone example, one I'm still puzzling over, is the Focal Elear. That open design has the most detail I ever heard in headphones, even more than the Eikon, plus extreme dynamics (they scale up so big vs softer passages that you jump). Overall, they do not sound in any way warm or relaxed: you're just bathed in detail & dynamics. Yet oddly enough, they don't seem all that bright. Nevertheless, all the dynamics + details give me a headache. Not at all relaxing, lots of detail--but not spitty & obviously unbalanced/peaky in treble. I need to listen more to figure that one out.