1. Listen to their best Demo CDs. CD’s, not LP’s. You don’t know if the TT system/cartridge alignment/anti-skate is properly done, so eliminate that potential problem. Something great might not sound great.
BTW, having both CD and LP versions of these at home is a great way to refine your system’s balance, then knowing the CD’s separation, make final cartridge/tonearm/anti-skate adjustments, then compare CD to LP.
2. Separation: 3 guitarists playing together, side 2, tracks 2 and 3. And, the subtle differences of the guitar type/string type variations
https://en.wikipedia.org/wiki/Friday_Night_in_San_Francisco
3. Specific Voices
a. Casandra Wilson (including great musicians, lots of specific bass, and imaging).
https://en.wikipedia.org/wiki/Blue_Light_%27til_Dawn
If her voice wanders off center as frequencies change, no no.
b. Duet: Barbra Streisand and Donna Summer, incredible even if not your music type
https://en.wikipedia.org/wiki/No_More_Tears_(Enough_Is_Enough)
hear/identify their individual and blended voices, are these great speakers or what?
c. Richard Burton’s voice, and a whole hellofalot of sound effects
https://en.wikipedia.org/wiki/Jeff_Wayne%27s_Musical_Version_of_The_War_of_the_Worlds
d. Annie Lennox, Eurythmics, and Dave Stewart’s electronic manipulations
https://en.wikipedia.org/wiki/Sweet_Dreams_(Are_Made_of_This)_(album)