Hello All
I am glad you all enjoyed the shootout and thanks for all the kind words
Adding felt to the tweeter face will tame the sibilant sound produced by the tweeter, help with diffraction and re-radiation. We preferred to use open cell 1/4"tall x 3/4" wide foam installed on either side of the tweeter because it is easy to find and install, It is self sticking. You can find this at Home Depot in the weather stripping department.This is the same department to find the rope calk
I wrote claimed freq responce because most often than not we have found that advertised low freq extensions are not obtained in real world applications
Happy New Year All