[dvenardos]

My bad Steve. I must have been having a bad day. 

That is not at all what I said.  I merely said that absolute phase is a consideration when combining an inverting mains amp with a non-inverting subwoofer amp or vice-versa, hence the phase switch on most/many subwoofers.

Much of the further discussion was addressing other posters who were confusing relative phase between L and R speakers with absolute phase of the stereo signal.
 
Steve