Bipole woofers, until how high hz are they awesome?

[OllBoll]

Hello there, I've wondered this about bipole woofers...

Lots of people here have tried them and love them, but until how high hz does thier bipole arrangement give superior sound?

In other words: Where can I cross over from the Bipole woofer to say a Bass Reflex / Horn speaker without disadvantages in sound quality?

Is the bipole awesomeness mostly in the non-direction-hearable area at under 80 hz or is it higher, so that one ideally wants stereo bipole woofers?

// Olle

[GM]

Ideally you want to XO them around 1/3 WL between the two, though some folks claim they still do OK at 1 WL, so let's say two 15" have a center to center (ctc) spacing of 30" = ~13560"/pi/30" = ~144 Hz or ~13560"/30" = 452 Hz, so a range to experiment with to find what sounds best to you.

GM