i have a 5.1 system with a pioneer sacd/dvda hooked to an onkyo tx-595ds receiver running 3 pairs of speakers-2 sets of main/front speakers utilizing an ORIGINAL set combridge sound works ensemble speakers with paired passive subs and pair cambridge model 11 3way bookshelfs/the rear-satellite speakers are pair very old unidirectional homemade 30+ yearolds and a center channel/can the icbm be used with passive subs in this setup and will it be worthwhile

What do you have powering your subwoofers? Also, I don't quite understand the second pair of mains. Are they in the same room or are they for a second zone? Or are they your rear surrounds?

I suppose that if you have seperate subwoofer amps, you could put an ICBM between your player and your receiver for the main, center, and surround channels. The subwoofer channel would go directly from the ICBM to your subwoofer amps. The ICBM should help a bit to keep your crossovers set properly for all SACD and DVD-A material that's coming into your receiver via the 6 analog cables. It would also facilitate setting up your subwoofers as stereo subs.

Hope this helps...