Unfortunately I don’t even now what the hell that is. They are corner bass traps from ATS Acoustics.
But you think I should keep the air gap then?
Flow resistivity means how much air can pass through a material. Higher number = less flow.
Those panels are made of Roxul Rockboard 60 and Roxul AFB, which AFAIK have a flow resistivity of 27000 and 16600 Pa.s/m^2 respectively.
Without knowing the construction, I will just assume a 50/50 mix. The panel depth averages to 6.5" due to the triangle shape.
Plugging those numbers in, the absorption coefficient should be around .4 at 50Hz if they are right against the wall, and something like .48 with the 4" gap. Could be a little higher, don't know the details of panel construction.
That was a complex way to say "amir is right"