Interesting Blog post on the Lii Song F-15’s from my Supratek Preamp Designer/Builder.

https://supratekaudio.blogspot.com/2026/06/

On my DIY ZROB’s I have cluttered them up with Steve’s Fast-15 Networks Filters to tame/smooth the highs on the Fast-15’s.  I have also added a GRS Planar tweeter that kicks in at 600-20k facing the ceiling and a second self standing GRS Neo Ribbon tweeter that covers 3500-40k which I like angled towards the center while the ZROB’s are toed out.  Darn if they don’t sound good to me.  After the above article there may be some more tinkering in my future