10-06-15: Stereo5Are you sure about that? If the two speakers are not connected with the same polarity there should be a reduction in bass, as well as vague and diffuse imaging, and probably also a midrange that sounds strange. If there was truly no difference when the connections to one speaker (not both) were reversed, I'd have to think that something else is wrong.
Already thought about the phasing and tried reversing the leads on one speaker. Really no difference in sound.
Good luck. Regards,
-- Al