Phase of an AC outlet will affect your sound!! (...what?)

If you can detect absolute polarity on a recording, yes it could matter to you, but I doubt anyone could tell after mixing mastering and codeine for download!
Now in the studio you might notice some polarity issues on some gear depending on what leg and if it inverts or doesn't relevant to everything else on that leg. Polarity is the simplest issue to deal with between wiring switching and patch bays !

Bill I'm talking about in the audiophile sense, where somebody is talking about a finished production, where you have all kinds of phase shift induced by every stage blurring the absolute polarity, now I can hear where one channel of stereo is inverted real stove to the other, but trying to tell if the polarity of say Stairway To Heaven or a track in the record no !
I have endured audiophile conversations where somebody swears something is inverting phase , brought out the old clicker to hear the clicker is broken or that the CD must be a different mastering !

The familer with is key , but as I have said 9 times out of 10 when the system was checked.. And that's the thing I learned early on for everyone there are 9 who can't that will say they can! It's one of those Audio terms guys learn to impress, but many don't understand that phase is shifted through out a recording and the total effect can result in 180 or close of phase shift and if we add in the fact that their are very few dynamic speaker systems that are phase coherent through their entire operating range ( the lowest operating range of any driver requires a lot of phase correction ) and very few mics are phase coherent !

What's hilarious about many of those who pontificate just to seem 'grand' is their lack of understanding of electricity in general.

Many electrical circuits are not just positive (black) negative(white) and ground (green) but also contain a 'feed line' which is red. a feed line defies polarity in the AC circuit and almost behaves like a direct current line. YET, it is part of the Alternating Current spec. And then there's 'residual return'... and three phase power, up-conversion and down-conversion, electrical current purity loss (85% at best) etc etc... and that's just what I have learned as a layman through various electrical and electronic pursuits.

Anyhow, a great electrician is vitally necessary for any recordist or audiophile, one who will specify current flows, as much current purity as possible and of course, power conditioning.

Be well folks, and don't lick the black or red wires.

I worked with a very famous guitarist known for his killer groove parts that was producing an artist - and I was engineering for that record.  He asked for anything from 10-50 sample nudges, and I couldn't believe it, but he could reliably feel 20 samples.  I purposefully tried to trick him, moving 10 forward and then 10 back, and he would say...."hmmmm....doesn't feel like they moved.  Give em another 20."   And then he was satisfied.  After working on the most incredible minutae, I began to be able to start feeling it too.  BUT, I don't WANT to go that crazy.  Not for me.  Music is not about perfection for me.

Point being - if you CARE that much to listen THAT hard, and you are gifted in that aspect of sound, it's amazing what you can hear.

Wow, Interesting. I haven't poured over ever word of this thread, but are you guys saying that AFTER you've recorded someone, they think that it's 20 samples behind?

In the old days of two-prong, non-grounded receptacles it was possible to plug in a  two-prong power cord "backwards" and everything would still work, although at an increased possibility for a shock hazard. This was because "hot" would be on everything that was supposed to be "neutral", and vice-versa. There was nothing on the receptacle or the power cords to designate direction or polarity. You can see this on old guitar amps. Sometimes flipping the cord cap in the receptacles would minimize noise/hum. After a while devices were manufactured "double-insulated" to reduce that shock hazard. Also, as time went on, receptacles were manufactured with one slot larger than the other and the plugs on the power cords were designed to match. The larger slot designates the "neutral" current-carrying conductor while the small slot designates the "hot" current-carrying conductor. And of course, at some point in time, a grounding pin was added which results in the modern three-pin receptacles and cord caps that are in use today, at least here in the United States. But be aware - just because a receptacle has a grounding pin does not mean that that point of utilization is properly grounded!
It should be noted that "neutral" and "hot" are NOT THE SAME as positive and negative. This is a common misconception.
There is usually more line "noise" on the neutral than on the hot. This is because all of the return current throughout the premises is picking up garbage as it flows throughout all of the various circuits throughout the building. All of the neutrals are tied together at the service panels and this tends to amplify all of the line noise. ( this is a very, very simplistic explanation ) We've all heard that our audio power source should not be on the same circuit/phase/leg/etc. as florescent lighting or lighting with dimmers or appliances such as refrigerators and the like.
So, with regards to audio equipment, if it's possible to plug in a device "backwards"- as described above - , then it's possible that that device can pick up more line noise and not operate as efficiently or quietly as designed. I think this is what is being alluded to on page 8 of the user guide. However, they are using the term "phase" erroneously. And, if the premise wiring is correct, with a properly installed three-prong receptacle, this should be a non-issue anyway because their device is manufactured with a three-prong IEC power connection which (should) make it impossible to be plugged in and powered incorrectly.
Basically, what they are saying is make sure your point of utilization is wired correctly.

It really shouldn't matter with modern equipment that uses properly designed power supplies. Svart seems to be the resident guru here on RGO with regards to this sort of thing. Hopefully he will chime in.

Exactly. In our country, I don't think we even use a center tap transformer. 

So I guess I can safely disregard an idea of a single phase power outlet having a 'polarity' or 'phase' and having a neutral and live wire inverted shouldn't make any difference as long as the gear I'm using has a proper PSU circuit built in it.