Thorsten,

you will notice my comment contained the phrase IME , not IMO, therefore I am qualified to point out that not time aligning the signal below 100hz will have a noticeable impact on the perceived sound quality. This was discussed on the forum some years ago before you were here, but a search might be useful.

You also failed to address the issues of the second harmonic and vertical axial mode. Any reasons for that?

 

Your directional loudspeakers are not directional at the frequencies we are discussing.