What tracks offer the best left right separation?

Proper imaging is one of the biggest goals and best aspects of my system, especially small groups.

My best track for listening for proper balance and final anti-skate adjustment is this LP, all 3 guitarists play on side two, tracks 2 and 3, thus strong separation and strong center information is there.

https://en.wikipedia.org/wiki/Friday_Night_in_San_Francisco

get both CD and LP versions to help get it right.

Live crowd noise can help also, IF the stage is centered, crowd big enough to give 'equal applause, cheers', as this one is.
..................................

After research of many reviews, one example

https://www.audioappraisal.com/audio-technica-at33ptgii-review/

I selected my cartridge based on it's superior channel separation (30 db) and tight channel balance (1 db). 

https://www.audio-technica.com/en-gb/at33ptg-ii
................................

Toe In for Imaging

I have 3 wheels on my speakers (more weight per wheel than 4, no leveling refinement issues).

I can adjust the toe-in (luckily I have a symmetrical wood grid floor with paper dots I squished down in the joints for reference).

Myself, centered, IF separation is over-done, I toe-in more than normal.

Two of us, little table between us, to maintain nice imaging: I aim the left speaker at the right chair; aim right speaker at the left chair. That gives a wider center, and maintains very nice l/r separation. It's the same method my DBX 100 Video speakers use by design. You are dimensionally closer to the speaker on your side, thus more volume (as usual), but you get more direct thus more volume from the opposite one aimed directly at you. Works.

http://www.hifi-classic.net/review/dbx-soundfield-100-135.html
..........................................

The reason I like to have remote balance from my listening chair is because some tracks benefit a Surprising Amount from a Very Small balance tweak.

Some recordings, the singer is off center, i.e. Hot Sardines (she leaves room for the tap dancer), some the vocalist wanders about, you don't know, so use the test tracks to refine balance; then the CD to know what the engineers intended, then refine your anti-skate knowing that.

................................

I saw the Hot Sardines live in NJ, awesome. Bought this terrific album:

https://www.amazon.com/Welcome-Home-Bon-Voyage-Sardines/dp/B07NBD1QDF

What the heck, trombone/horns supposed to be left, piano far right, did the engineers screw up? Did I leave my McIntosh Mode Switch in Stereo Reverse (nope)?

Turns out, the 2nd LP, live at Joe's Pub, NYC, Donna was there that night. Small slightly off center stage, the Piano was left, horns right. And the separation is not as wide as when I saw them live on a centered wide stage.

So, I used my Stereo Reverse to ease my mind's search for 'correct'. After a few listenings, I now can accept both the Toronto and NYC recordings as presented.

Eurythmics, Blue Nile come to mind for very purposeful l/r effects

https://en.wikipedia.org/wiki/Sweet_Dreams_(Are_Made_of_This)

https://www.discogs.com/The-Blue-Nile-A-Walk-Across-The-Rooftops/master/35779

Cassandra Wilson, dead center vocals, terrific musicians very distinctly located

https://en.wikipedia.org/wiki/Blue_Light_%27til_Dawn

When you get really good imaging, then as I keep yapping,

BASS can be directional, in my case front facing 37 lb 15" woofers, monster magnets that I luckily inherited. Consider them a stereo pair of subs.

I learned here, it’s not always the fundamentals, but the bass overtones that give directional cues, thus Ray Brown, Ron Carter, Charles Mingus is ...... over there, a great part of enjoyment of small groups.

That’s why I recommend a stereo pair of subs (not swarms); self-powered; front firing; no ports, or front ports.

Huge systems, sub swarms, for true bass fundamentals, very low crossover, are usually combined with mains that can make directional bass on their own, that’s for the big boys, I’ve never heard a swarm, except bees.

btw, those woofers were originally in a console on 8" legs, facing downward. My first separate enclosures were identical box shape/volume on 8" legs, just transferred the front panel with 2 horns (wrapped in new linen). Woofer still downward facing. Current enclosures are taller to get the woofers front facing/directional, more box volume for a bit more extension, horns higher, tweeters aimed at seated ear height. Electrovoice engineers helped me design the enclosure, with optional rear port. Big room, far from walls, I opened the rear ports. Now, here, smaller space, I covered the ports inside. In each case, bass became more directional.

...................

Tilted Back helps imaging I think (wood block above two front wheels within the skirt), to change the angle of reflections off the floor and ceiling), and for time alignment of highs/lows.

Ortofon Record tracks 1-8   
Digital seperation is 3x LPs, ANY format.

The Ventures, serious seperation.

Electric ladyland
Jimi Hendrix, duh.