The seven π crossover points are 250Hz and 1.6kHz.The upper crossover is almost exactly the same as the crossover in the three π and four π speakers and for the same reason. Summing is good, response is pure and directivity is matched, providing a nice uniform pattern over a wide horizontal angle and with good spacing between vertical nulls.
The lower crossover is 1st order with a lot of overlap. We want wide overlap between midhorn and bass bin for best integration. It tends to make the transition invisible and also reduces floor bounce because of the vertical distribution of sound.