i would imagine that some of these astrovans and suv's with massive walls would have nearly the same if not a larger internal box volumes than the actual air space remaining inside the vehicle after the walls is built.
Is this ludicrous for me to think this?
seems like it would be a totally different ball game in terms of design if this was occurring. Anything that need to be accounted for when this situation approaches?
I would think at some point, once the box is larger than the cabin space, the cabin would then act as the box, but that's just my line of thought. i haven't had experience with walls so don't quote me on that.
In a wall setup, you are not just tuning the box. You also tune the cabin. In a way it becomes a big bandpass on wheels.
The hard thing about tuning this bandpass is your forward chamber (the cabin) is a leaking, flexing mess. You have to account for that and usually trial and error is all you have.
SPL is about pressure. A larger area compressing into a smaller one is also the concept behind hydraulics, which powers anything from brakes, forklifts and heavy machinery.
There are other factors involved but..............