Sonic difference between the two generations of speakers were not small, with the new models offering a more open and transparent sound, yet one that was also smoother and that more easily broke free from the speaker enclosure to create vivid images and deep soundstages.
The top model in the Reference II lineup is the RF-7II, which sells for $3300/pair, and which incorporates a 1 ¾-inch horn-loaded (of course) titanium tweeter that is said to leverage learnings drawn from the expensive, top-shelf Palladium models introduced a few years back.