David,
Why is a discussion of the suitability of the Cube driver for use in OB systems not an appropriate subject for this thread? It appears to be a thread about both the speaker and the driver.
While I have my doubts that this driver would be better sounding in an OB (because I think the designers would have tried it this way), I nonetheless think it should be an excellent candidate for such use for fans of OB speakers because of its overall competence.