My Esoteric DV-50 played them fine [same transport as the UDP-1 I believe], but the Denon 5910 does not play them...which might be true accross the board for the Denon players.
Is there a "universal" problem playing Dual Discs?
I have heard that several universal disc players have trouble playing dual discs in their higher resolution (SACD or DVD-A) modes. So, people don't purchase DualDiscs. Is that a truism? I just bought a C-J modified McCormack UDP-1, and there are several DualDiscs I'd love to hear in high resolution.