The typical sub has a phase switch-normal/reverse-0/180*. I have played with the switch before but really can't tell any difference although I'm sure with meters, etc. there are differences. My new SVS PB-12 (not Ultra so no comments!! :-)) is being delivered tomorrow (hurry! hurry!). Is there a simple method of setting the phase switch? Is this a key setting for the sub? How often do people set it at some in between setting and how do you measure that?