THAM15 - a compact 15" tapped horn

[Rademakers]

+ 1 on using thicker panels. If you're using a couple of hundred Watts 12 mm is fine, around 1 kW per driver I would prefer at least 15 mm myself. If that's truly going to be 2 kW (the DS100 will handle that) then 18 mm is a good idea.

4) IIRC slimming down the width just reduces the resonant outputs, it flattens the response. Increasing the horn length is your best bet.

Buried driver enclosures have a different sound characteristic to me. I think I hear the distortion in direct radiator enclosures or maybe it's the mechanical movement of the driver. Buried driver enclosures hide that sound.

For Cubo Infra and similar designs, in 'direct radiator mode' there is more in band THD present (~40 - 60 Hz). This does help with the impression of 'faster bass' and sounds better with faster BPM (120+) music. In down-firing mode, the lack of THD sounds better with low BPM (und thus most hip hop songs). My guess is that it's the backwave that comes from the driver, via the chamber or port, that travels through the cone of the driver that is responsible for this effect.