Riddle me this....

Recordings are phase inverting about 50:50. The only thing that changes is that records that were out of phase now will be in phase and vice versa. That is why a switch to invert phase is highly desirable in a digital component.

@mahgister @lewm 

On this one I have to unfortunately disagree with you both. In my experience somewhere around half of all recordings are polarity inverted. While that means, that it doesn‘t matter which way you connect your speakers, the actual playback will be out of polarity about half of the time. That‘s why having a polarity switch in the digital domain is so highly desirable. It is actually an advantage of digital over analogue to be able to correct this, and: yes, the differences on a decent system are very audible.

BTW: @mahgister‘s explanation as to why is by a country mile the most lucid I have encountered on the subject.

@dogberry

It‘s precisely the initial pulse of the wave that defines phase, or for the purposes of this discussion more accurately polarity. Think of a wind instrument being blown rather than sucked ( in analogy to a speaker Diaphragm moving out rather than being sucked in with the corresponding air flow. And it is audible despite what certain theorists claim ex cathedra.

Just as an aside: this is the major advantage of a point source over multiple speaker units interfering with each others‘ phase.

In the analogue domain it‘d have to be mechanical and thereby more accident prone, I guess…Where polarity is messed up during recording, there‘ll be a change in degrees with in most cases one setting preferable. Since the advent of hi-res audio, polarity consistency seems to have moved into focus for recording engineers.