Okay......best single box reference CD player

Can't disagree with Emigene.

Anyone ever heard the Electrocompaniet Emc 1-UP or compared it to some of the gold standard players mentioned?

Recently had a chance to audition the new Boulder 1021 CD player at a local dealer. My comments will be prefaced by the dislaimer that listening to anything outside of your home system makes analysis challenging. The Boulder CD player is ultra-expensive (24K). However, it is a beautiful piece, and has some uniques attributes in how it reads CD's. Anyway, it was paired with Wilson Maxx 2 speakers, and the lower Boulder series (800) preamp and powers amps. We A/B'ed with the Esoteric X-01 player. The Boulder was clearly superior and offered improved detail with a lack of grain and hash that one would not have noticed if the Boulder didn't remove it. Whether it bests any of the others previously mentioned I cannot say. It is likely worthy of mention in the uber-CD player category.

What's unique about how the Boulder reads CDs and is it measurable somehow outside of subjective listening?

I heard the Boulder at the distributor house, great piece of equioment, but i will pay 24k? surely not, mostly due that the futur is in other way, PC based digital fronts, memory players, but less expensives....