Got 2 admit Ive been waiting for u 2 pop up n tell me how stupid my comment bout blowing thru filters was after @bob31 said ur the HVAC expert!
Nice 2 know i was talking sense!
Ive decided that for my extraction Im gona use 4" plastic pipe elbow (rather than a right angle as this should cause less air resistance meaning less noise?!?) coming out the top of my tent into a straight short length of 4" plastic pipe connected to a 4" fan directly connected to my filter
N for my air intake Im gona go passive n use a straight length of 3" or 2" plastic pipe going from tent to soffit (tents in attic)
Hopefully Im right thinking solid plastic pipe will be quieter than flexible ducting?!?
Couple this with the fan Im getting which has a sound level of 24db n hopefully everything will b as quiet as can b?!?
Sound ok to you?!?