Usher BE-718 Crossover Question

Does anyone know what type of crossover is in the Usher BE-718... Phase Perfect... Butterworth... or Linkwitz-Riley?

I believe that Danny Ritchie of GR-Research designed that crossover. You might post your question on the GR-Research Forum on Audiocircle.
Mtbrider... I took your advice and asked GR-Research if they could answer my question and received the following response:

"They really do not use a textbook style network. It is an asymmetric network ideal for these drivers."