High Efficiency Speaker Asylum

Felt to absorb tweeter reflections?

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This Post Has Been Edited by the Author

Due to the particular position of my tweeter relative to the midrange horn's prominent upper lip (see picture) I'm using "acoustic foam" around it.
It does help tame some diffractions, resulting in more focused stereo image and more disappearing speakers.
However, I still have a nasty peak centered around 8KHz which I feel might be caused by the foam being ineffective at some frequencies?....
I'm thinking replacing it with a suitably thick layer of flet. Or something else. At least on the upper lip.
What are you guys thinking?

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