It seems that the Due' may not be the perfect match for the Ref IIIs. I just copied this out of Srajan's 6 Moons review of the Ref.III's:
"Also, the CDT used in the Dué is not the same. Its dispersion and low-frequency extension are far more limited. Ditto for its 3-inch midrange drivers - although the head module of the Reference III does look like a slightly larger Dué, it is mechanically, structurally, electrically and sonically a very different animal altogether."
Hmmm...looks like we will have to bug Mr. Gallo about this issue, as Mr. c-bugbee suggests.
"Also, the CDT used in the Dué is not the same. Its dispersion and low-frequency extension are far more limited. Ditto for its 3-inch midrange drivers - although the head module of the Reference III does look like a slightly larger Dué, it is mechanically, structurally, electrically and sonically a very different animal altogether."
Hmmm...looks like we will have to bug Mr. Gallo about this issue, as Mr. c-bugbee suggests.