That would be a great option indeed. What’s the price of these?
I’m not sure even though we’ve used them at shows quite a bit. You might inquire with John at CAL.
It’s not the price, really, but size. That is: few pre-assembled high efficiency subwoofer options are available, and the ones that are from the hifi-oriented segment would likely cost a small fortune the likes of Cessaro, Living Voice (not least) and a small handfull of others.
It sounds to me as if you are not familiar with the Swarm sub made by Audiokinesis. Its 1 foot square and 2 feet tall. Its also meant to be placed as close to the wall as possible because its designed to take advantage of the room boundary effect (+3db/octave going down from 100Hz). This allows it to be small and easily placed. In my installation I have the drivers facing the wall rather than the room, to insure the output really is within the room boundary. They work quite well- I use a pair in tandem with my CAL T-3s, which by themselves are flat to 20Hz (and are 97.5dB). Because there is a standing wave in my room, there’s no bass at the listening chair despite the speakers’ capabilities.
So I use the Swarm subs to break up the standing wave, and now the bass is good anywhere in the room. FWIW, IIRC the Swarms are about 3500/set (don’t quote me on that) so are very reasonably priced and give you excellent bass.