4 ohms and 8 ohms create about a 3 ohm load, I think. I'm still and forever will be a techno idiot. If I had a 4 ohm cab and a 16 ohm cab what would my impedance be? (This sounds like a dumbass riddle.) What would be the drawbacks of running a system like this? I have a 4 ohm cab in transit. I'm hoping one cab will do it for me. (I think it will). But, if ever I wanted to try two cabs, could the above be a possibility? The (HUGE) problem would be finding a 16 0hm cab... Just curious. Thanks.