I remember reading the the "Magnepan" version of the ICBM just doubled the normal crossover frequencies. The lowest setting would then be 80hz and the highest would be 240hz.

Here's a quote from a "Soundstage" review of a Magneplanar system that states this:

Quote:
Still, the problem remained that Magnepan needed to find a solution for filling in the gap between most surround processors� standard 80Hz filter and the MGCC2�s octave-higher 160Hz limit. Magnepan went to Internet-based Outlaw Audio and negotiated for the creation of a Magneplanar-specific version of Outlaw�s Integrated Controlled Bass Manager (ICBM). Purchased separately for $325, the Maggie-specific ICBM offers a selectable high-pass-filtered center-channel output appropriate for use with the MGCC2. With selectable filter settings as high as 240Hz (the frequency labels on the ICBM are unchanged from the regular version, but Magneplanar owners will know that actual values are double those noted on the ICBM panel), the ICBM actually filters out the bass frequencies that would be destined for the MGCC2 and "recombines" those filtered frequencies into the front right and left speakers (recommended to retain the proper timbre and center imaging), or directs them to a subwoofer, or directs them to both. Outlaw Audio�s standard ICBM is a full-featured bass-management system that is extremely flexible and sonically transparent. As discussed by Jeff Fritz in his SoundStage! review, it is just about mandatory for multichannel DVD-A and SACD music systems given the horrendous omission of any kind of bass management.


Here's the link for the full review:
www.soundstage.com/revequip/magnepan_mgmc1_mgcc2.htm