You're welcome, and let me expound on some of your observations.
Yes, the granite was just a prototype, the aluminum is extruded and can be filled with sand/shot or another preferred dampening material. The cabinet shown is cherry, it also comes in piano-gloss black and maple.
The drivers are similar to the HGS in terms of magnet and voice coil, but use a new carbon-fiber cone material with a ROHACELL foam core that is lighter and stronger.
The control stage (Digital Drive) is completely digital. It offers the eq capability, high and low pass crossovers, and complete control for crossing over the 18 and the 12 drivers as desired. It is all RS-232 controllable and we've also digitized the HGS accelerometer so that it now checks and corrects for cone anomolies some 15,000 times per second.
Any of this stuff migrating to the "regular" HGS subs? Velo was working on some HGS subs with eq awhile back. Weren't they supposed to be introduced at CEDIA or is it the upcoming CES?
Randy, Wish I had more data for you, but plans for the evolution of the HGS series aren't finalized yet (although we will likely announce something sometime next year).