Lee, if each individual speaker is connected internally with the correct polarity, then taken together they'll be in phase with each other. If the test you ran showed correct polarity in each that should answer the question. The battery test Randy linked(1.5 volt can also be used, although cone movement is less)can double check this. Also, using the M22s is yet another test.

If it appears that the amplifier is the culprit, connect different channels to see if removing one of them(possibly wired internally with reverse polarity)from the circuit also removes the phase problem.


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Enjoy the music, not the equipment.