You are absolutely correct. It smooths the treble from the stock white filter but there is still some sparkle in the treble. Excellent recommendation.
I would call the white filter with the acoustical foam from the black filter not the blue plus but more the white minus filter. So to summarize we now have the following filters with the screens from brightest to warmest based on a quick 20 minute listen:
Any of filters without the foam or screen (personally I do not like the sound because of its incoherency and shrill sound).
Black filter without the foam.
Stock white filter
(I image the white filter with the blue foam would fall here)
White filter with the foam from the black filter
Stock blue filter
(I image the blue filter with the black foam would fall here)
Stock black filter.
That is eight different sonic signatures assuming the options in the parentheses are correct.
Ok I'm going to have to throw one more into the mix "I promise this is the last" I was told that it's possible that the foams could be of different density so I pulled the blue filter foam out and put them into the white filter as this is our go to filter .....after listen to both I prefer the blue filter foam with white filter ....so I'll let you judge it for once and for all it's between the black foam and blue foam insert with white filter....I'm staying with white filter with blue filter foam combo...let me know what you think I think☺️