i know i'm going to pay for this, pero this thought made me wonder.. the question is if we need to understand to appreciate it better? Well, my answer is yes. I'm not saying that it's the only way to appreciate it better, but it could be a way.
but if the question is do we need it to appreciate it? No. I appreciated jazz way before i even knew them.
let's take a joke for example. If you don't really understand the joke, how can you laugh at it? or how about a solution for a programming problem, how can you see the beauty in how he used different mathematical elements in order to know which is the shortest path of getting from point A to point Z if you don't really understand the shortest path algorithim? I think music is the same in this case.
i'll base some of my personal experiences here.
I watched a diana krall concert live before when i was a kid. I fell in love with the music and i tried to learn it. After a few years, i (kind of) get how the music is created - well of course i listened to it most of the time and tried to learn through ear. And i think the listening in this case is also a part of gaining knowledge on music, much like listening to computer geeks talk about computer stuff all the time, after a long time you get to understand what they are talking about. Anyway, so here i am now, wishing i learned and became more knowledgable about jazz. i couldn't understand a thing before, i just knew it was beautiful, and now i know that if i get to watch that again, it'll be definitely better.
So here i think listener B understands the music better.
but then again, there is a flaw to the question - i don't think someone who is a devout jazz lover can be someone who is not knowledgable in music at the same time. if you listen to jazz long enough, you learn the different progressions, sequences, turnarounds, the diminished, the augmented, the 7th, if it's in the right pitch, if he hears the right notes - it's just that you don't know how the rest of the world calls them. well, i think i learned this way, before i gained knowledge from the internet and other people.
Anyway, just a thought - i just want to be heard.