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

I’ve read a phrase here that stated “help, my Steinway sounds like a banjo”. I always recollect to this phrase when listening to solo piano. Months ago I was invited to a friends home and they have a vintage Steinway Baby Grand (which was just tuned). I had him play a few things and also played with the piano myself (the little I can bang on the keys) and I noticed there is a little muffle when the the hammer hits the strings. The hammer has some sort of velvet on it and so the instant that hammer hits the string, the note is actually not as airy and sharp. For the Tube amp guys here I would explain it as more of a Mullard EL34 sound vs Gold Lion KT77. Hope that makes sense.

@edcyn 

thanks so much for that explanation.  Totally makes sense and gives me more appreciation to listening for details with piano playback in my system.  I also have to add that playing at the proper volume would get you closer to realism, just don’t overload the room.  This discussion is quite interesting with everyone’s feedback and vast knowledge and experience.