Phase inverting problem

Kirkus is right in that in some ways the phase is preserved- but I think if one looks into the equipment the interest of the designer will not be seen to preserve the absolute phases of the inputs.

I've used a lot of boards over the years and serviced them as well. What I have found over and over is that while they maintain certain standards, for example pin 2 of the XLR might phase non-inverting, that they are not so interested in what the ramifications of that fact is beyond the idea that all the channels get the same treatment.

IOW the unit may well be phase inverting from input to output, but no provision for that is guaranteed by assuming that pin 2 of the XLR is indeed noninverting relative to the input. It can only be assumed that the relationship will the same with *all* the inputs. Its a tricky nuance!

Some equipment uses a modification of the original balanced standard, in which pin 2 is non-inverting. Sometime in the 70s or 80s, European equipment went to pin 3 non-inverting. This practice has shown up in some Japanese equipment as well. This stuff is all over the industry! Unless someone has taken the time to make special cables that convert from the pin 2 convention to the pin 3 convention, the result is there is simply no way to know what is up.

Since it is reasonable at this date to assume that this equipment is everywhere peppered through the industry, its very safe to assume that 50% of all recordings are out of phase and the other half is in phase.

Having been a recording engineer for many years we very carefully checked all wiring of microphones and consoles to be phase correct. But we are really talking here about keeping relative phase consistant. The absolute phase of the end product can be reversed and will in all likelyhood be undetectable. Remember to mikes wired for correct phase when placed near each other will produce out of phase information due to acoustical leakage. In mastering we used osillascopes to check for any severe out of phase information particularly in the bass for lp tracking issues. Relative phase and absolute phase are two different things

All of this discussion doesn't negate the reality that sometimes inverting the signal does sound better. As I said not very often, I grant.

I also see no reason to assume that absolute phase is 50/50. It is a cliché.

I took an absolute phase test on the internet, using earbuds.
I scored 50:50 which is pure chance.
If I can find it again, anyone care to take it?

On my home system, I can't tell except on a very few mainly solo instrumental albums. The rest? Up for grabs.

Some equipment uses a modification of the original balanced standard, in which pin 2 is non-inverting. Sometime in the 70s or 80s, European equipment went to pin 3 non-inverting. This practice has shown up in some Japanese equipment as well. This stuff is all over the industry! Unless someone has taken the time to make special cables that convert from the pin 2 convention to the pin 3 convention, the result is there is simply no way to know what is up.

Atmasphere raises a very important point here, that is the difference between the "American" (pin 2 hot) and "European" (pin 3 hot) XLR pinouts. The "American" pinout is the EIA/AES specified professional standard, but this is of course not at all consistent across different types of gear, i.e. microphones are virtually always wired with pin 2 hot.

I didn't mean to imply that recording and mastering engineers in general give any special attention to absolute phase, but as others has pointed out, relative phase is absolutely critical. So in practice, when outboard gear in the studio (i.e. a compressor, mic preamp, effects unit, etc.) is wired to the patchbay or console, any potential polarity reversals *should* be corrected. Otherwise, this can cause some really weird issues when the output is brought back into the console for mixdown, or routed to headphones on tracking.

So a thorough, necessary attention to relative phase is highly necessary, and absolute phase much of the time just comes along with the ride. This is especially true given the ubiquity of Pro Tools . . . when one purchases a CD that's digitally recorded, mixed, and mastered, it's a pretty good bet that a positive pulse on the vast majority of input channels' (microphones') ADC corresponds to a positive pulse on the output of your CD player.