Shadome
I understand the skepticism - total bass output from a sealed volume + given radiating surface is certainly limited by physics. I just don't think that this limitation has been the practical problem.
I have a radiating area just under that of a 12" sub + two small enclosures + high power/long excursions. The total output from that combo is more than sufficient for my largeish ( app. 6,000 cu ft.) space even at the highest spls I'd personally require. It is powerful, clean, punchy and -to my knowledge - obeys the laws of physics. It is also nearly, but not quite, ruler flat (in room) to 25hz at typical listening levels
Presumably the audible distortions associated with that combo of box volume, radiating area and excursion have been significantly reduced due to better drivers, more rigid boxes, and more powerful amps. Real world performance is getting closer to theoretical limits. That's why I don't think that the laws of physics were ever the real limitation. I imagine that there's plenty of room for further improvement which will likely come primarily in the form of even smaller boxes rather than greater output or reduced distortion since those parameters have already been (IMHO) adequately addressed for (all but the largest) rooms out there by the better subs on the market. While I am certain that many people will disagree with that statement, that has been my experience.
The other real improvement has come in the area of integration. Modern devices provide room analysis + PEQ + a flexible crossover, allowing far better integration of subs to mains.
IMHO, the result has been eye (ear?) opening. I'd say the performance I'm getting from 25hz to 150hz would be difficult to improve, given the ultimate limits of my ability to discern improvements in this area beyond this level. Of course, I'll acknowledge that, if you heard the system, it's certainly possible that you might reach a different conclusion.
Marty
