I must repeat, the double CLS are not stacked so you do not need ceilings any higher than you need for a single pair. The speakers are wired in series exactly as the gentleman has described and the load to your amp is not as severe as with one pair.You only need to find a used pair of CLS and 1 extra speaker wire per channel( I use 6 separate 3 foot wires)This is a very inexpensive,upgrade that anyone can perform. There is no external crossovers, no extra sub woofers and interconnects, no pain in the ass positioning of a sub to where it sounds best( like I have done trying to get The Depth to disappear)no soldering wire, replacing or upgrading internal parts or connectors,no power supply upgrades,no power cord upgrades.None of the things audiophiles spend small fortunes on trying to improve their sound.If you find a used pair in the $1000.00 range that is the least amount of money for the most improvement you will ever make to a single CLS system.No expensive time consuming learning experience here.The fun and the proof is in the pudding. And in putting together a double pair.I would feel grief to those who spend five times as much money and effort futzing around with power cables and speaker wire upgrades in a vain attempt to better the sound of their single pair.Good grief, don't knock what you don't know and have no hands on experience with.Do you still think that if man was meant to fly he would have been born with wings?