A long long time ago I had an opportunity to buy 16 ohm JBL woofers that were used once for a concert. I had passive crossovers at the time so my solution as a very young man was to build a second set of A7 cabinets so I could parallel the 16 ohm woofers. Now I want to use Altec 416 woofers... So the question is should I load all 4 cabinets, two on each channel. Impedance isn't an issue now as I use active crossovers. I am wondering what the plus's and minus's are considering mutual coupling issues. Given the large size it is enough of a wavelength between drivers to cause havoc...