Scan-Speak 10F JMLC horn combo - large dip troubleshooting

[Defo]

Just make a + of two thin but rigid peaces of for example paper.
Stick that into the throat and see what happens.

I tried it with thin cardboard without any luck. I may try again though with some more comprehensive measurements.

 

[Defo]

Tested several phase plug shapes today using ethafoam, and found that a thin layer, a little larger then the dustcap gave the best results both on and off axis. The downside is that off axis response gets worse as on axis response gets better... But I will find out what gives the best comprimise.

No idea what that little piece does in practice tho...