Most Challenging CD

'power' is not a challenge, the softest sheen on a voice is way more of a challenge.
((as an aside: I remember in some 'sword' movie where the Crusader cuts a thick metal rod with his sword to 'impress' the Ottoman. Then the Ottoman pulls out his sword and floats a fine silk scarf up into the air and as the scarf floats done, it cuts ITSELF in two on the unmoving blade of the Ottoman's curved sword. two different ideas of what a sword should do!))
Same way with a stereo, brute force or subtleties?
I am far more concerned with the subtleties than the brute force.
Try Sinead' O'Conner singing "Nothing compares to U', or 'I do not want what i haven't got' or 'bewitched Bothered and Bewildered' and listen to the sheen surrounding her voice. Spectacular! When it is right, that is a good sign. Especially from a CD player!!
I guess I am just not interested in gut massage.

“Music is the space between the notes” – Claude Debussy

Bantock: Fifine at the Fair - Handley/RPO on Hyperion. Huge dynamic range.

Hmmm, interesting contrast Elizabeth brings up. Made me bring up Sinead on the system and enjoy some of her stuff I haven't listened to in a while. I get it. But I don't discount the qualities that I think Muralman is talking about. I don't think it's so much pure brute force, or a gut massage, though those things might occur to one in listening to passages like that. But I think he's talking about the ability of a system to clearly separate and define fairly complex and diverse audio events occurring simultaneously, all of which does indeed require some power, but not just power. It may deliver a crescendo without clipping, but if you loose the sense of the orchestra, and the crescendo becomes a huge wall of sound with no depth, texture or tonal complexity, then some potential of the recording is lost. In my experience that has been more challenging for various systems over the years than the aspects of subtlety and nuance that are also very important, that I'm taking from Elizabeth's post (and are actually more important to me as well since music I listen to most seems to highlight more simple and stark arrangements). In other words there have been systems in my experience that can attain what Elizabeth outlines that have failed miserably at the challenge Muralman proposes, but I have not experienced the opposite myself (not to say it's not possible, but usually if a system can do what I'm gleaning from Muralman's post it can achieve what Elizabeth proposes). I'll give you a cut that has both, albeit certainly not as stupendously dramatic as Muralman's example. Very challenging to a system nonetheless, and also challenging in the opening half which emphasizes beautiful, stark vocals that I think are exemplary of what Elizabeth describes: Mine would be Antony and the Johnson's - Hope There's Someone. The first half is just simple, stark beautiful vocals by Hegarty, accompanied by his piano. There is a startling sense of presence and immediacy. Somewhere around the middle it builds to him almost pounding away at the bass notes while his voice wails out in layers of broken harmony. If a system can separate out those layers and not turn it into a muddled two dimensional mess, it passes my test.

I am noting all of your CD favorites for this system torture test. Certainly, as has been noted, soft kissy passages sung by a sultry siren have to be kissable. Also, the ability of a system to play loud passages while simultaneously tinkling a triangle is also just as necessary.

Jax2 mentions the necessity of keeping the orchestra intact during loud crescendos. Come to think of it, the finality of Bolero is a good test. On most systems it sounds like a raging wounded bull. I know. I have had plenty of those systems.

The problem of citing voice is that discussion can dissolve into how many angels on the head of a pin. How many times have you heard someone saying, that's not what she sounds like on my system. There's no arguing that.

There are clues as to whether you are getting a good rendition of the singer. How human they sound is one. Can you hear them breathing in?