Quote: next test was to just place my drop base over the duct & redo the test. straight away the peak value jumped up. so sorry to say Mr P. drop bases actually straighten the air & improve airflow.
I/m glad to see your testing.. but that wasnt what I seen on the filter flow bench at work... but its good to see your testing... by the way I tested with a lid on it with a filter... what your pulling is direct and the inner radius helps flow as you see... thats why I run a stack or as its called.. a ideal entry