The response from the back at 180° actually shows more output than to the sides because now the magnet cup of the tweeter acts like a diffraction device. It is the same phenomenon that can be observed with the reflector version when measuring straight from the top of the speaker only to a much smaller degree.
From a mono listening test with this reasonably flat response it is obvious that Demokrit-T has become a very different speaker now compared to the reflector version only because of this "little" additional directionality. Hence, the equalization will be somewhat different as well. The cross-over point might also change long term.
The looks: Well...I needed an easy and quick retrofit so that I can compare both versions without building another set of pipes. The mounting is stretched copper lead wire, which is used as signal conductor at the same time.
Is this yet another Pluto inspired design ? No !
Although they share driver arrangement and the goal to minimize diffraction, the directional behavior is very different. If I would talk of similarities, then Demokrit-T is something like the so-called ZDL speaker (Zero Diffraction Loudspeaker) started by Joachim Gerhard.
Stereo listening tests and the equalization process have started now. Before that, I had to modify the tweeter mounting because the tweeter was too far in front of the pipe and thus creating phase issues in the cross-over region, which could not be fixed by any amount of time delay (visible in the pictures above). The tweeter is now further back, right above the edge of the pipe and the cross over region looks much smoother.