Zone 2 is almost always full range; few offer bass management for zones. 49Hz isn't too bad actually, and I would imagine they can handle a full range signal, just don't go trying to send a ton of bass heavy stuff to them. Your calibrated signal is not calibrated for those speakers in their alternate locations, so it may not give you what you truly matched levels if that is what you are after, but they should essentially play more easily once crossed over.