@mswale yes it’s like an animal farm, the more you have, the more it continues to cost. Kind of like when I walk into a rich person’s house, my first thought "nice but I would not want to pay the utility bills!"
Since you sound like a vibration guy, how would I stack them? What would I put between the subs and the speakers?
Still working on my vibration solution. This stuff gets stupid expensive. A little piece of metal with a few springs, $600 EACH!
For the subs, you got to find a spot where they add bass, but not standing waves. A corner of the room, or in the middle of the speaker is a good starting point.
I found these cheap little squares, they are under a lot of my equipment. Put them under the footers of the subs, if you stack, put them between the 2 subs as well. They work surprisingly well. ISO pads