I thought that since we are getting closer to the first official Terraform XLs entering into the world, that I would start a thread on it...there's another individual that has also ordered a pair (he can jump in here if he wants to, but I don't want to publicly name him yet!
* High Output, Ultra Low Frequency specialty subwoofer design
* Two(2) 15" drivers (internally mounted)
* Two(2) 18" passive radiators (HF chamber)
* large enclosure with slot vent tuned to ~12Hz
* DSP Controlled (manufacturer only) ICEpower amplifier (2000w/1200w sustained)
* Tentative dimensions: 52" x 22.5" x 28"
* Weight: Likely to approach 200 lbs
For Mark's Terraform/Terraform XL, he has coupled the high frequency chamber to the 18" passive radiators, and the rear drives the large slot vent which is tuned to the low teens. The Terraform XL doubles the number of drivers and PRs and more than doubles the power, but keeps the box size to less than double a Terraform.
As I get some more info and others chime in, I'll keep this original post updated with info.
Hopefully, they will be finished within the next month.