No, the most certainly are not more efficient in the bass region! Do the math. .5dB is just about the margin of that error so that increase in sensitivity isn't going to amount to a hill of beans. However, the 2.5 ohm impedance right in the middle of their bass pass band is going to draw more power.
As for the line arrays theory, generally, coupling breaks down once wavelengths exceed the on center distance between drivers. That distance on the 936 is under a foot so they don't really break down as a coherent mechanical unit until 1000Hz. They're down about 18dB at that point. My guess is that's why you see some odd behavior from the bottom 2 as the top one tapers off more shallowly.
It seems we're generally in agreement. In any event, I'd expect the Kanta No.2 to have better controlled bass considering the only difference between those drivers and the 936 drivers is a significantly more linear motor.
As for the line arrays theory, generally, coupling breaks down once wavelengths exceed the on center distance between drivers. That distance on the 936 is under a foot so they don't really break down as a coherent mechanical unit until 1000Hz. They're down about 18dB at that point. My guess is that's why you see some odd behavior from the bottom 2 as the top one tapers off more shallowly.
It seems we're generally in agreement. In any event, I'd expect the Kanta No.2 to have better controlled bass considering the only difference between those drivers and the 936 drivers is a significantly more linear motor.