The Flip-top!

Here's the end result of my work. This is a view from in the attic space, having entered by swinging open the manifold. It is extremely heavy- especially with the drivers.

It did exactly what I wanted; I was already able to use it to get into the attic to add more insulation.

Were I to do it again; I would use the same design, but make it lighter by not using doubled 3/4 MDF. I think birch or high quality ply, and maybe just 1/2" MDF. A manifold design doesn't vibrate like an array would and just has to cancel its opposite speaker.