What is the most challenging music to play on a stereo?

Plenty of good suggestions - but here is my question - what design in your equipment should you seek to eliminate all of your issues?

Happy Listening.

1.  Music I'm familiar with.

2.  Solo piano.

Tonality - Human Voice. Male or female, It shouldn't sound tubby, chesty, cupped, or nasal, Emmy Lou Harris Eva Cassidy, Aaron Neville, Mark Knopfler (His voice turns to mud on a lot of systems)

Dynamics - A big symphony, Beethoven's 9th is the first that comes to mind

Detail - Acoustic guitar. Pat Metheny and Charlie Haden. "Beyond The Missouri Sky"

Soundstage - Any well recorded live album, regardless of genre, classical, jazz, rock. Dan Hicks "Where's The Money" on a goodsystem will put you in The Troubador circa 1972. The first time I ever heard Magneplanar Tympani IIIs biamped with Audio Research D-76s and D52s with this album was life changing.

synthesizer music, Larry Fast, Jean Michael Jarre, Mike Oldfield.

The most challenging anything to do it that which you do not like. Polka? @elliottbnewcombjr  glad you are still here, you seemed pretty down the other day