In my case, as in Alonski's (thanks for the great thread), being a musician has greatly aided my critical listening as an audiophile. Though currently not a pro, I started real young (in high school and college) by helping support myself by playing in bands up and down the colleges and clubs in Central NY. As a guitarist, I vividly remember the "dance" I did, along with the bass player and the drummer while we were playing; we would each lock into a part of that drum kit; I'd eyeball the snare, the bass player the kick drum, and we'd all be intertwined, each accenting different portions of the measure and different parts of the drum kit, but all gelling into one mean groove machine. It was hypnotic.
I also played percussion in orchestras, had classical training on piano, guitar, as well as my favorite style of electric guitar: fusion with an r and b twinge.
I strongly believe that having all of this experience really helps me pick apart a lot of the stuff that I hear. And reading that Peter Cuddy document confirmed that. Because pretty much most of those questions roll around my brain when I'm in critical listening mode.
Thanks for sharing that document, Alonski, and also for all your great replies.
Have a good one!