square measures 11"x12" opening size. Might be a bit iffy.
Just for kicks I threw down an old bath rug on the cavity floor, and a
12" x 18" USPS shipping box fit perfectly up at the front of the rectangle.
Right there that cut the sound by at least 15%.
I do plan on using some type of sound absorbing board and line the rest
the walls in there.
First I wanna see why I'm getting such a back flow
of air pushing down from the filter. Shouldn't a return intake draw in air only???
I'm calling the installer back. Maybe the blower motor could be turned down a tad, if that's even possible.
Some things need fixing on this install. I'm can feel a few minor cold air leaks at some areas at the evaporator, and there's a stream of air coming down at the plenum where it enters the attic.