Agreed. Since your amp is 4 ohms min, you must pair your current cab with another 8 ohm cab. So, a single 12 paired with a 2x12 means both cabs split the amps power evenly, which further means the 212 gets to split it's half of the power in half again, leaving the 1x12 to carry on with DOUBLE the power of the other 2 spkrs. Recipe for disaster. A 2nd 8 ohm 2x12 will be your best option, preferrably, and identical Schroe 1212L.