HI John, The 4khz 12db/octave 2 way Xover will limit beaming by the woofer and also better split the frequency (more controlled than a physical rolloff). IT should significantly alter the sound of the speaker, whether for better or worse is for you to decide. As you may know, most speaker designers would NOT do the physical rolloff, but would rather do the 2 - way Xover. Breakin may be an issue though in my experience it makes little difference. -akhilesh