A friend of mine recently built subwoofers to extend LF SPL capabilities (and a bit of FR extension also) of his K+H O300 studio monitors with the 830952 12". Since I was the one which drove him to try this particular Peerless I am allowed to show his speaker setup here (I knew there would come the day and asked beforehand):
There is a very long thread on a german forum on this, if there is some bigger interest on it I might translate the essentials of it and post that here. If you scroll through you might find some pics, as well simulation and measurement plots. It manifests the complete history of the project over several months, from first thoughts, building and testing prototypes (with differnt amp and xover) to the final stages. The 830952 comes into play at page 5 and most of the cabinet building stuff is on page 7.
I can tell you this guy did a very good job, all the woodworking and finishing is really excellent (and he dared to spray the alu cone in black, to remove that "I'm the boss"-car-hifi look of the driver). Also he did al lot of decent room tuning, as his small room wasn't benign (lots of modes at rather high frequencies).
And, last not least, this driver sounds quite good, in this application it really blended well with the O300, both being CB designs. The plate amp with its xover was a bit tricky to tame (we had to do extra electrical measurements to get phase/freq issues right). Because of the massive breakup at 3kHz a steep xover is needed. The monster rubber surround seems to need some serious break-in time.
It's a really good subwoofer driver. Listening to other retail subwoofers (including amp, etc. like KEF's or Rel's, etc...) I could compare it with a subwoofer of 1000 euro's (but that's not unuasual for diy subs).
The sub goes really deep and can be used as well as vented (tuned to 20hz you can get f3 easily at 20hz with 125Liters) as closed (f3 about 36hz with about 67Liters).
I've got it tuned to 22hz with 100L giving me an f3 at 23hz. It sounds very tight and quick.