Assuming that the rest of the audio chain is properly polarized (no device is reversed) then positive or 'In Phase' sounds best. But if one (or an odd number of devices are reversed polarized) then 'Out of Phase' would be best.
The way to easily tell is, to listen for the lowest octaves on music that actually has music in the 20-60Hz region. Listen for the sharpest or most percussive initial impact of the instrument. On suitably well recorded music even cymbals and guitar and piano will have an added leading edge 'sharpness' to them. Conversely if the music is 'reverse polarized' there will be a 'softening' of the leading edge and a lack of 'thump' in the extreme bottom end.
The best way to think of this is to visualize hitting a drum and either creating a positive pressure wave front or (if reversed) a negative pressure wave front. The ear/brain is able to discern the difference based upon the leading edge pressure polarization.
Symphonies that wail on the big kettle drums, are some of the easiest to tell the difference. But once you train yourself to hear the differences, you can even hear differences listening to piccolos. And there are more subtle differences as well but they take more effort to figure out which is 'best'.
Of course all of this is predicated on a suitably resolving system and music source.
JJ
