"So does anyone see any issues doing something similar to this with my build when I do it? I like the idea of downfiring because I have small kids and don't want them to go poking and playing around with the new speaker...ever! hahahaha...I will be using the SI 18 D2, I am assuming it doesn't have any issues with sagging in a downfiring configuration?
I haven't decided to do this for sure yet...I may just do the standard cube, inset the driver and make a speaker cover for it too ...that seems to keep them from messing with my currents subs.."
because the port is firing into the floor, the tuning **may** come in a single hz or so lower, no biggie.
it appears to be a great design and i'm sure that we will see more like it!
iirc i ran the numbers on the si18 and it came out right at 5% which should be fine as far as concerns about "sag".