It is looks like a small company in Germany that makes some kind loudspeakers and among them there is one looks like ambitious project: 5 ways installation:

http://www.horn-kultur.de/englisch/prod_mk5.html

It looks interesting. Let see what they offer. I do not know what drivers they use. Still, let see what I do not like. Obviously the over-sized mouth of the upperbass channel is not good. The two distinct borders on the peripheral of the horn mouths are not good, and completely not warranted. The frame around upper MF and lower MF is absolutely not interesting and could be much better. The bass sections, I never like such bass bins as they are bottom-closed. They are fine for a cheap 2-3-way acoustic system but in my view not useful for a pushy 5-Way system. The 8R impedance for the 106dB speaker is too low in my view for use ordinary transformers.

What I do like.  The same bass sections, not the topology but the facts the they make bass not to be coupled to the MF island. 

What I found interesting. The black rectangular channel between MF and upperbass.  It may be MF and what I call MF might be a tweeter. Of it might be a large electrostatic tweeter as Wilson used to use in this top model WAMM. I experimented with something seminal in 2002-2003 and I do like the idea of very large radiation surface for tweeter. The crossover at the bottom I find also interesting: it has 4 vacuum capacitors. This is an interesting twist.  The vacuum capacitors of this size would be around 500pF-1000pF. It is theoretically possible to skew up the crossover Q and to have insane amount of inductance and to have ultra low capacitance. This would be absolutely foolish crossover but it will have coils the size of large barrels. We do not have it in there; we see regular coils and large caps. So, most likely the vacuum capacitors are used juts as the bypass the caps that are visible on the left of the crossover. Not bad idea but there is a moment in it. The ultra low values of the vacuum caps makes the vacuum caps kick in at very high frequency, much high then auditable frequency even for bats. However, the vacuum caps had very large contact surface with a LOT of metal on them as the vacuum caps meant to be use at tens thousands volts. Well, from what I’ve seen a conductor caring signal has a transition from regular diameter to very make with large diameter and excessive mass of metal then it does not sound good (the high-end crap with name WBT speaker connectors are notorious for that). So, I am not sure that the use of vacuum caps is justifiable in there, it makes good picture for sure….