Do you play an instrument? Helps in speaker eval?

Yes, absolutely, but...

Have played bass, trumpet and guitar for over 40 years. Experience in amplified, unamplified, sound reinforcement, etc. Have sat in audiences untold times, and right in front of trombones at full bore in orchestras...here's the catch.

Wolf has it right on the head. A few years ago, I was in a very high end dealer on the East Coast, at a Transparent cable unveiling/demo. There were about 20 people present.

Now, I've used Transparent and tons of other stuff, down to 24 gauge cotton wrapped silver, so this is no knock on expensive cable (that's another post). Anyway, "A" and "B" samples were played of an acoustic bass and french horn. No one in the room commented when asked about hearing the differences. Since I'd bobbed my head, I got called on and said the harmonics were different and the attacks/leading edges were obviously different. The demonstrator seemed satisfied with that, until I added that moving the microphone just a few inches closer or further from the bridge or the bell could also make the same difference.

I wasn't asked for more input.

I play the drums. Admittedly I am just getting into high-end audio, but my uncle has been an enthusiast for as long as I can remember. He has a dedicated listening room and often invites me over when he changes things around. He usually plays a track that I am familiar with, and I can tell you that I absolutely hear differences between cables, amps, etc. I typically pay closer attention to the percussion instruments, and he has definitely had set-ups that sound very lifelike.

I have played violin in symphony orchestras and attended live concerts for years. Yes it helps in judging audio equipment .

I record myself playing guitar and (sort of) singing in my listening room/home studio all the time. I have a high quality interface for my mics (apogee) and the record/playback chain is reasonably high quality for a home studio arrangement - other than the mics which are good, not great.

When I A/B myself performing, it never sounds right on playback. When I A/B my instructor, it's better, but never very impressive, relative to good commercial recordings. While I don't think such comparison is very useful in evaluating a system that will be used to play commercial recordings, I do think the playback quality differs audibly when you change out gear. I rotate speakers from time to time and, in the end, I'd call it one flavor of wrong vs another flavor of wrong.

FWIW, on the same basis, my guitar teacher thinks that the SQ of my system is the best he's ever heard.

I hear differences in cables, etc. in my tweaked and fussed over hifi, and the system is revealing enough to notice gigantic differences among all recordings...I doubt this is from a lifetime of playing music and hearing shows, it's more about listening closely and giving a crap. I'm sensitive to bad live acoustic guitar sound because it bugs me, so I've been on a never ending search for an acoustic pickup system that I like (I've owned too many that are just "OK")...and recently found one that feels good (LR Baggs "Anthem"). I think my experience just makes me more pissed when I'm listening to a show where the sound sucks, or a lame stereo someplace.