The jaw drops.
These are really is on the highest technical level.
Since the entire series of speakers has the same baffle width and driver lineup, only a modified crossover is really an option. The crossover frequencies are unfortunately only given in the specification of the S7t (500Hz, 1.1kHz, 4.4kHz).
View attachment 161099 View attachment 161100
Sources:
Audioholics,
EAC
The crossover concept as a whole has special aspects.
At the crossover frequency around 1kHz, probably no typical allpass filter, like a Linkwitz-Reiley filter, is used, but a "constant power filter" like a third order Butterworth filter (which were very common in the past) or something similar.
The frequency response curves of the vertical measurements are an indication of this.
In very
simplified terms: The negative angular frequency responses form a hump, while the positive angular frequency responses form a dip (or vice versa). Together, this results in a constant sound power response.
This can be seen very nicely in the floor and ceiling bounce - just compare this with a
typical LR filter.
View attachment 161088
If you want to have a closer look at the difference between different filters in the vertical plane, you
can do so here - "Crossover filter - Effects on the vertical radiation".