I have dual NHT subs, and related NHT SS dual amps. I have three systems, each with separate pre amps. One has dual amps outs, one a sub out, and one with only tape outs. I route all of the outs to a Chase RLC remote controlled unit as a switcher that goes to each of the NHT amps. I do not use the NHT amps to feed the three different sets of speakers that I use individually, all driven by tube amps. Since the line out of each pre amp is different, the Chase unit's remote is used to adjust the output of the NHT sub amps. Works well, gives a lot of flexibility. For WAF purposes, each sub is in a front of the room corner, but I have been testing various other placements. Nothing finalized yet.