I have a mackie amp that is 2/4/8 ohm capable in stereo. I am building a cabinet that is either 2 18s or 3 18s. I would like to do the three eighteens since I will be able to make enough volume in each chamber since it is custom built. The drivers I was going to use though are 8 ohm. If I ran three of these it would be 2.66 ohms or I could do two drivers @ 4 ohms. Is it safe to run @ 2.66 ohms even though it is an odd ohm load? Maybe the internals are made to run at either 2/4/8?