Ok, I'll bite on this topic. It was discussed in Why were CDs recorded in 16-bit/44.1khz? but was very out of topic for that thread. I hope this is ok to start a new one, Steve. So the first question is: Is absolute polarity audible? The answer is yes, given that you listen to a certain waveform that is asymmetric. This has been known for many years and is also explained by the physiology and psychoacoustic effects of hearing ("half way rectifier"). The sound of such signals change in pitch and timbre when inverted. Some expect the difference to be in "attack" since the waveform change - however, the difference is most audible as a change in pitch and timbre. So you cannot actually hear the changed phase, but only the effects of it as frequency spectrum change. Examples that you all can test yourself can be found in the thread linked above. Now: the second question: Does it matter when listening to music? I would say >99 % of cases: No. You need to have asymmetric signals and not not much other things going on. These other sounds will mask the change in pitch and timbre of a putative asymmetric and inverted music signal. That said, you could probably find some examples where this could be audible. But then: what can you do about that? Absolutely nothing, since you are unaware of that it just happened.