I recently got my M-Pulse 360 and the semi parametric eq is a dream. It's awesome. But my 15 inch Son of Bertha can't handle it. Not only does it clip, but it slaps the back of the grill. Now if you're standing there looking at it is sort of scary to see it move that much. I am running my 360 at 4 ohms with the Goliath III hooked up also. What should I do? I like the added bass of a 15 and I want something that can handle my Mesa. Should I replace the speaker, the entire speaker/cab, or just go with an 18? My Mesa screams with my current settings on the semi parametric eq. I'm clipping my 15 at barely above 1/4 master. Now I know how to use my eq very well and didn't go crazy just boosting stuff. I don't want to change any settings. You guys got any ideas? I guess I could consider getting something like a 2x15 + 2x10 setup, but I bought my 4x10 not too long ago. Would Mesa 15s kick about the same as my SWR? If I decided to sell my rig, what would be a good price, seeing as the Son of Bertha is a year old... Thanks in advance.