Another factor is the design of the loudspeakers playing any given recording. Very few are phase-coherent; planars are, of course (one reason for their generally high-quality sound), but most multi-driver dynamics are not. Vandersteens yes (at the x/o frequency, at least), Wilsons no. The drivers’ polarities may be inverted relative to one another, in order to optimize the speakers frequency response and/or waterfall plot performance. If that requires running one driver with inverted polarity, so be it. Dave Wilson, for one, does that regularly. The Eminent Technology LFT-8b magnetic-planar and Vandersteens models 1, 2, and 3 use 1st order (6dB/octave) cross-overs between drivers, and are phase-coherant. If you are listening to a speaker which has it’s drivers working in opposite polarity, good luck listening for a change in absolute polarity upstream.
