Some pre soundproofing measurements.
Upstairs media room noise floor:
Downstairs noise floor:
Top line is used as the baseline for the basement at the MLP. It is measured at the MLP in the media room upstairs at -10 reference. The measurements below it are with the same sweep on the subs upstairs but measured downstairs. They are at a few different places in the basement near the MLP at standing and sitting levels. I could not get close to the proposed MLP in the basement since my USB cable was a bit short, but the three measurements are a good mix of the best and worst scenarios down there.
I also ran some test tones downstairs on a pair of Titan 48 horns and measured at the MLP first downstairs for the in-room SPL, then I measured again upstairs at the MLP while playing the same test tones at the same volume. I measured with the door to the basement open and closed.
Downstairs SPL from the T48 at the MLP:
Upstairs SPL at the MLP, door open:
Upstairs SPL at the MLP, door closed:
The goal of this test is to remeasure after mass is fixed to the ceiling and then again afterwords when additional layers are added with decoupling, then again with the door mass-loaded and gasket seals.