I have received a newer set of HE-560 yesterday and so far they are as good as I remember the first pair being.
I am told that these have the modified sealed production baffle. With test tones the bass extends very deep, and 16Hz tones are felt. I didn't feel the 16Hz tones as well with the first pair, but I could hear 20Hz. Without the first pair I can't say if the 20Hz is stronger now, but it's pretty strong.
These have a 1/4" plug now, but the cable sheath is not the same as with the HE-500 cable, so it's not the same as the old cables.
Now I resume doing more comparisons with the HE-6, using the HE-6 via XLR and the HE-560 via 1/4", on Eddie Current ZDT and EF6 amps which have both jacks.