Invert ?

If anyone determines their absolute phase (total system) is not of the correct polarity, and have no switching to use in the system, simply reverse the leads on the speaker cables at the speakers. 

Thanks everyone for all these great explanations. One question   How do u know if a recording is out of phase? How often does this happen in a recording? What is the best way to tell ? 🤷‍♂️

@OP, there's no way to tell except by listening. MWH777's post explains it well. To the extent that it is audible, the effect is likely to be more obvious by playing some simply mic'd recordings .

 You can hear it. Fortunately, when two signals are badly out of phase, it’s easy to hear. When two similar tracks are mixed, they can sound thinner, tinnier, or harsher, indicating that they have a phase problem.

@yogiboy  Thanks. That makes sense.