What exactly is critical listening? Who does it?

Critical listening is the gateway to whatever is there on the other side of the fence.

Of course I’m going to critically evaluate components that I’m spending decent money on, and then when it comes through the door I’m gonna be very critical to ensure it does everything I was hoping for.

I’m gonna listen to all kinds of music that I’m familiar with critically evaluating the changes and hope to be hearing with a new purchase.

When I was younger, I never had the awareness to listen very very carefully however I was very mindful of how well music filled the room vs crappier systems which were disappointing.  

I think you can balance critical listening and other types of enjoyment at the same time.  Unfortunately, we all have an instilled discipline within us that prevents us from avoiding this ongoing critique of everything we do and see. 

Presently, I’m done buying all this audio stuff aside from potentially upgrading speakers. So the critical side of the mission is fading away, thankfully.  Maybe I have to buy a car and I have to now critically evaluate all the new electronics and stupid digitized Dashboard which is horrifying, I don’t like a having an iPad embedded in the dashboard. 

I'd suggest critical listening can be broken down into two sub modes, one judgemental, the other not. Judgmental mode is for evaluation, listening to sound quality, qualities in order to compare, contrast to some reference.  The other mode of critical listening is intentionally careful listening which should bring about a sense of heightened consciousness in which music, artistic performance and sound quality, qualities all serve to maintain undivided attention to this single activity of listening to music on a high end system. Music, artistic performance and sound quality should all have great salience such there should be a conscious acknowledgment and appreciation for each.

When I was younger, I never had the awareness to listen very very carefully however I was very mindful of how well music filled the room vs crappier systems which were disappointing.  

By 'younger', are you referring to your days in the first grade when you were checking out different power conditioners?

@immatthewj 

way earlier.

For me, critical listening changes future listening. It improves apprehension, enlarges vision, refines discrimination, and creates new standards. Music gives me the object full of meaning; listening critically involves grasping potentialities in that object which were unseen. Subsequent experiences of listening are thicker, richer. 

In other words, listening is not just a mere medium for emotion. My ability to listen, critically, helps me discriminate among goods. And as soon as I begin to compare such goods -- this singer sounds more detailed, that soundstage is more realistically presented, that bassoon sound richer and full of character, etc. --  I am doing criticism. 

Criticism requires inquiry into the conditions and consequences of the outcome valued. It is needed to enhance perception and to allow for appreciation of the same thing over time. Again, it accomplishes this by uncovering new meanings. Criticism is the path from "merely enjoying" something to enjoying it as reflectively validated.

Criticism allows me to choose more knowingly because it reveals the conditions and consequences involved. It also makes it possible to express my likings in an informed way. Criticism is the main reason an audio forum, even the hobby, can exist at all.

@westborn Regarding Socrates, here’s my take. It’s a common misreading to think that Socrates’ claim that "the unexamined life is not worth living" is about "self-improvement," generally. It's not really "be all that you can be," in our modern self-help sense; rather, it’s actually deeply intertwined with his view that "It is better to be dead than wicked."

An unexamined life is one where someone passively accepts societal norms, desires, and opinions without critical reflection. They don't "think about stuff," crudely, but more specifically, they don't think about values -- what is honesty or courage or compassion. They either ignore the world around them or just say "whatever" or even, "everyone is different." Meanwhile, they become increasingly  ignorant about what is really good or evil -- and so become vulnerable to acting (or passively accepting) what is morally wrong. They "turn a blind eye" to the pain and suffering around them, and their possible complicity in that suffering.

In other words, the ignorant person -- the one living an unexamined life -- either tolerates or passively allows evil acts. This is a form of self-harm, in Socrates’ view, as it harms their most valuable possession: their character (or soul, in his Greek version).

Socrates thought that  our moral integrity was paramount, far surpassing physical life or material possessions. To live in an unexamined way, then, is to become vulnerable to wickedness, and this inflicts the greatest possible damage  on oneself.