I am not giving you a pass in this. That so called passive sub is not really a sub. At least not close to my definition. The issue that concerns me more than anything is driving a mid down to 100 Hz, that makes it a bass driver in my book. I don't think anyone can call 100 Hz bass with a straight face. The performance of this speaker could have been bettered with a smaller and more elegant design.
Here is the performance of my surrounds. I designed and built these in1984. My first design using computer assisted design. There were designed as my monitors to record concerts for live broadcasts. They are high spl. speakers.
This is the FR.
You can see that the F3 is somewhere between 45 and 50 Hz, and virtually identical to those RBH speakers with their so called built in passive subs. My speakers also have a 12 db. and not a 24 db. per octave roll off, so my smaller speakers have more low bass.
Now the above design is now 40 years old. I know darn well which speakers I would rather have, and it would not be those speakers with a passive crossover at 100 Hz. I am going to call that a very bad design concept.
Better results could have been achieved in a smaller speaker at no greater cost.
This is their current location as my surrounds, giving service at 40 years young.
That RBH design has marketers input all over it. My view and I won't change it, is that its design concept is invalid, and far more could have been done with less.