What exactly is critical listening? Who does it?

"critical doesn't necessarily involve judgement."

Correct:

Critical

I define critical listening as focusing only on the music-maybe not the precisely correct meaning. Lots of people-my daughters for example-always have music on, but its in the background, while they are doing other things. I bought them both a Morel Biggie to replace Alexa and they consider it high end.

When I listen critically, I try to devote at least an hour and try to clear my mind (with my mind, not a lot of deep thoughts to get out of the way). I'll admit that I enjoy the music, but also enjoy judging how its reproduced both in terms of the engineering, and by my equipment. For me, the performance of the gear is an integral part of the experience. I realize I could be voted off Audiophile Island for that damning admission.

Interesting question! After some thought I think I have something worthy to add here... I think there are different types of "listening". 

One type is analytical. This is where the listener/audiophile is actively searching for different qualities being reproduced by their system. Is the bass right? Is there enough detail? Are the highs too strident? How's the soundstage? All these things and more are being actively examined for satisfactory performance. Changes, if necessary, are made. Equipment purchased/swapped out. Speakers moved. Room treatments installed, etc. This is where I think many audiophile get trapped and don't get to move onto the next kind of listening.

This second type of listening is the "appreciation" kind. This is where the listener is not listening to the performance of their system but to the performance of the artists. They are listening to become involved in the music. Be it Vivaldi or Floyd, Fusion or Baroque, they are allowing their minds to delve into the art and relish the emotions being generated.

Is one more important than the other? I would suggest that the former, once satisfied, helps promote the ease into which the listener can fall into the latter. That said, it's not a straightline progression. After some time of appreciating, the analytical might creep back in when some recording or other somehow doesn't satisfy as it might. Then the mind asks "Why?" and we start the cycle again. 

It might be analagous to the way an artist changes the way they perform a particular piece. Maybe they do another arrangement or place different emphasis on different notes or passages. Conductors have different interpretations of orchestral pieces. And once satisfied, they perform their art in the way that suits them... Until next time they feel something isn't quite right and the mind asks "Why?".

Thus it's my belief that Critical Listening is not just a reviewing tool for analysis but can also be the means that keeps an artist's work in flux as well.

Happy listening.

Or maybe another aspect of critical listening is criticizing Rachmaninoff for use of French horns when he should be using trumpets for a passage that clearly needs a emphasized crescendo.  And at times limiting use of violins in the background.

And sometimes the tympany is just too overwhelming don’t you think

Yeah...those damn tympany players need to be reigned in...the good news for me is there are close to zero of them in my normal listening...small jazz combos, shoe gaze banjo, mope metal, mope mope, no mope, etc.