might have to cheat a bit on driver and try APT50 phenolic as may have more HF power/rattling than my 806 & 807. maybe a hacked KSN1016 with stepup transformer would work too (or Leson)
anyhow - got majorly confused looking at Johnny's 5Khz horn drawing due to conical ponted piece and what appeared perhaps to be throat/plug assembly.
(a few more pix including one of driver mount would have helped)
for my intent just seems like need the "lips" front - anything beyond this concept.
are dividers helpful in mini-Smith-horn? - or just create interference lobing?
luv sound of these waveguide - and 1" version wasn't shabby with big-gap Karlson coupler loaded w, 18" haha.
I think DSH critics may not have response tailored correctly
if can ever figure out & get 5Khz built and smooth then will ask about diy slant-plate rules.
gimme hints on dims, etc which work well.