Treated or un treated dust cap for monitor 10/SDA

DracoAmericanus
DracoAmericanus Posts: 112
edited November 2011 in Vintage Speakers
I have a question that may be a no brainer but i noticed that on the older monitor 10's the dust cap is felt or a treated materal that does not pass air but on the SDA series they use a rather transparent black clothlike material for the dust cap, any one have any thoughts on that? The theroy i have is the material on the SDA will move some air though it and aid in cooling the voice coil, any other thoughts on this?
There is no cure....
Luxman M117, SDA SRS 2.3, rear monitor 10, back rear bose 4.2, valodyne sub and 2 Onkyo m-504 amps Onkyo TX-NR709
8mm, 7.62x39mm