Reversing absolute phase

Hi there,
I heard this phrase before and was wondering, what does it mean and how do you do it?

Any specifics would be appreciated.

Thanks in advance!
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The nice thing about this tweek is that it costs nothing, and will keep you occupied for several hours!
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This comes up about once a month. Since there is not and never was an industry "standard" for absolute phase, LPs and even CDs are not consistently created equal with respect to phase. In fact, on an LP, one track can be out of phase (or phase inverted) with respect to the next track. Therefore, if you want phase to be "right" for each and every piece of software, you are going to be jumping up and down a lot swapping the hot and ground connections of your speaker wires, even assuming you can hear the difference. IOW, if your preamp is inverting, it will still be correct about 50% of the time. And if you are obsessed with "proper" phasing, you had best acquire a preamp with a built-in phase switch. Just be sure your L channel is never 180 degrees out of phase (not "polarity") with your R channel. That DOES sound bad.
Just because recording engineers are too lazy to bother with absolute polarity does not mean that having it does not sound better. You are correct that in many multi-miked recordings, some mikes may be out of polarity and others not. I would suggest that the industry should establish a standard.

I don't think I have ever stumbled onto an out of phase recording. I have heard instances where people were not careful and hooked up the cables wrong.
There's a bit of confusion here between these posts.

In any electrical situation, there is a positive and return leg of the circuit. Sometimes the return leg is synonimous with ground and sometimes there are discreet positive, negative and ground legs. Microhone lines are usually "balanced" three leg circuits with positive, negative and ground legs. Although there is some standardization that pin one should be ground, pin 2 positive an pin 3 negative, it is very easy for positive and negative to be reversed or for positive and ground to be reversed in unbalanced circuits. This ususally happens either by miswiring or in polarity inverting circuits, which are quite common. In certain circumstances it can require alot of attention to detail to ensure that polarity is consistent as well as "correct."

This means that not only is there an opportunity for entire CDs or LPs to reversed, one to another, or for polarity to be reversed from cut to cut within an LP or CD, but also one mic to another within one cut. This last issue makes it impossible to determine a consistent polarity for that cut/album and is very common. Even audiophile engineers who care sometimes have problems ensuring correct polarity.
Miswiring is hardly an excuse. Since one polarity is often superior, it is too bad that this issue is ignored.
not an excuse, just a reality. The much more common issue is polarity inverting circuits. An engineer mus be cogniscent of the polarity of every unit in his arsenal of gizmos and make sure to align them. I would hazard that most modern truly professional engineers do this.
"Since one polarity is often superior." No it's not. They're identical. The CD or LP can be recorded in either "normal" or "inverted" polarity* and played back in either. It helps if the playback matches the recording, but because most speakers are not polarity-coherent (with minimal or no crossovers) anyway, it only makes much of an audible difference on the ones that are. This subject is a hardy perennial, but that doesn't seem to make for much clarity about it.

* And many are recorded in mixed polarity. I have discs where I can bring the vocalist forward or put him/her in the background depending on where the polarity switch is set on my preamp.
Also don't confuse "reverse" on some pre-amps (was poular back in 50's/60's) as when it says "Stereo-Mono-Reverse) all you are doing is swapping what came out of left speaker for what now comes out of right".So if your bass is more prominent in left channel and drums more prominent in right it will be reversed that's all.Some confuse this with above info on phjase.I wish more digital players had this and compresson which is so easy to add and if your system is in absolute phase (after using polarty check ) all the way through an engineer went the other way it can make a huge difference.Compresson is something I'd like o see for making Car CD-R's or low level listening.Had an Adcom GCP 750 that had phase and it mae huge difference on some recordings.
Dopogue, I have no idea why you would say that inverted and uninverted polarities are identical. On many recordings that just is not true. If by saying that "most speakers are not polarity-coherent" you mean that one driver is inverted, I would say that buyers should avoid them.

Mind you I am not saying that matching the polarity of the recording, if there is one, is a major contribution to the quality of sound, but it certainly adds to that quality.

this is a little confusing but I believe what Dopogue meant was that there is no qualitative difference between the two in and of themsleves, except relative to keeping the playback polarity the same as the original, which only shows up as significant on phase coherent speakers which refers not only to whether the drivers are alll connected in the same polarity but also to first order crossovers which maintain phase coherence throughout their range.
You're 100% right, Piedpiper, bad choice of word on my part. Apologies.
A few years back, I introduced the concept of proper relative polarity to a well-known recording engineer in NYC. He said it was never a practise in any recording studio...I was shocked and bummed. When I asked the foley artists in Hollywood the same, all I got were blank stares.

I learned how to listen for it from an old Madrigal/Mark Levinson national sales rep when I worked retail north of Detroit in the 80s, and have a copy of the Wood Effect...a small paperback explanation of why this is an serious issue for ALL audiophiles.

My recording engineer friend called me a few months after his 'schooling', when he turned in his first phase-insured multi-track capture for mastering to Bob Ludwig. Ludwig apparently makes a habit of listening to each of the tracks turned into his studio before the capture engineer leaves, and this time he asked if my friend had paid attention to absolute phase. For the first time, all of them were in phase...and he wanted to know if it was co-incidence or more!

When I heard from my now friend-for-life, he was three feet off the ground, ecstatic that his mentor had noticed that he had learned and applied something new!

I took this as a bigger good least Bob Ludwig can hear absolute phase, and makes a practise of correcting it with the multi-tracks submitted to him for mastering! Of course, it begs the question why Ludwig hadn't bothered to school my friend himself...

Three cheers for the golden ears! (although one less for selfish pride hindering the growth of many for personal profit, how much of Ludwig's reputation is from this single applied gift?! Although, if he is anything like me, he might not have been able to identify what was flowing from him as naturally as a blink or exhale!)

Even more kudos for the rest of YOU who notice these things...and keep an entire industry of maniacs kicking.

BTW, anyone who says this isn't an issue doesn't realize that the compression of air molecules happens before the rarefaction of any waveform that we can hear...except perhaps the duck's quack.

I've always wondered why those don't echo...
Gannon...How do you know that? Did you make some measurements? I have observed (while traveling in the Suez canal) that the bow wave of a ship is a trough before the crest. Likewise a Tsunami is preceded by the ocean going out before the wave comes in. In the case of sound in air...consider a drum. Surely the polarity of the sound wave will differ depending on which side of the drum you hear it from.

The behavior of a sound wave propogating in air is a whole lot more complex than you think. And anyway, as others have noted the polarity of signal on recordings is so mixed up that, IMHO, it is a waste of time to worry about it.
As one might guess, I agree completely with Eldartford and others who expressed similar sentiments. But it goes back to what I stated above: if you DO care a lot and if you CAN hear the "difference" consistently, get yourself a preamp with a phase switch, preferably on a remote control.
The Herron Audio VTSP-2 preamp has absolute phase on its remote. Attention to absolute phase via a remote is just one of the little things that add up to a great sounding system. It goes along with dressing cables, cleaning contacts regularly, running degaussing sweeps, etc. If we were normal, we wouldn't be audiophiles ;-)
The Aesthetix Calypso is another that provides this essential (to me) feature. Nice that it's also a great-sounding preamp.
Eldartford, given that hardly any manufacturer provides a way of inverting the signal, I hardly worry about polarity, but I know from much experience that one direction typically sounds better. Presently I lack any capability to change either digital or analog. It is real shame that there is so much disregard for correct polarity. If recording engineers were less lazy and music companies more concerned, such that we could know that all recordings had say the first oncoming sound as positive polarity, we could all just set our speaker leads one way and forget the problem. Alas, that is very unlikely. I am sure in the digital domain that software could just set every cut to onset positive polarity.
IMO, there may be no such thing as "correct" polarity on the recording end. There may only be such a thing as one polarity sounding better than the opposite one to a given listener at the other end of the electronic reproduction chain.
Lewm, I agree under the present circumstances.
A manufarturer's choice to include polarity reversal is based on budget and the sonic dgredation involved in the extra stage that most designs would require, and that of the switch to control it.
Piedpiper, I agree about the degradation. I had a Millennium preamp made by Siltech, with a remote switch to invert. I noticed that the best sound was to invert the speakerwires at the speaker but not on the preamp. It turned out to be an inverting preamp and did use another stage to allow inverting. I was hearing the loss in using the inverted setting. As you say some designs could easily provide this. All line stages with parallel outputs even if they just use a transformer could provide it without an additional stage. Parafeed designs could also.

Would it not be great were recording engineers to chose one polarity and stick to it? All you would have to do would be to decide which you preferred with your speaker connections and stick too it.
were the world that simple.
Tbg, If you do agree with my statement above, then there is no way that recording engineers could "agree to one polarity and stick to it". I'm not absolutely certain that my assumption is correct (regarding the fact that on the recording side, selecting polarity is not possible due to multiple instruments, multiple mikes, the effects of mixers, room effects, etc), but that's what I wrote. True, the recording engineer could decide whether or not to flip a polarity switch, much as we do on the other end of the repro chain, but he's only altering the polarity of a bunch of mixed sources that in and of themselves most likely are of non-uniform polarity.
Lewm, I just don't believe it is all that difficult. I helped mic a recording session of a jazz festival while at FSU. We checked at all balanced cables were wired correctly, that all the mics when we blew into them showed the correct output on the hot wire, and once all of that was done that we adjusted for any inverting stage. It took more time than ignoring any of this, but not much.
As a recording engineer myslef I agree with Tbg. You just have to know for sure what the poarity of your equipment is. The only caveat is when you're multi-micing with lots of bleed which is something to avoid anyway for this very reason. It is obviously easier the fewer mics and outbaord equipment you use. There is a standard as I mentioned above. It's just that most engineers don't pay enough attention to ensuring it all the way down the line to the point of it being a crap shoot whether any given recording is phase coherent within a given cut, throughout the allbum, or given phase coherency, which polarity it's in. So the question as I see it is not whether it could be but whether the industry could be effectively improved.
My leanring curve has shot right up, but I'm not 100% sure about what?

Thanks anyway for the intriguing discussion.
Following all before I'll try to be simple for you. I asume you want to ensure your system will correctly reproduce a recording which is 'in correct phase'. If I were helping you confirm this we would 1st play and carefully listen to a CD recording- that is known to yield correct sound when played through a system with correct setup-, paying attention to detail and clarity, dynamic swing and bass response and soundstage. We would then reverse the leads on back of each speaker and listen again. Hopefully we will clearly hear and agree that one way sounds better- clearer, more detailed, less sibilance, more exciting & fun to listen to- than the other. Obviously the way that sounds better is the way the leads should stay. I would use a recent "Reference Recordings" CD to do this as (Keith Johnson is respected for being fussy about sound) I know his recent recordings are correct. If you use a TT we would do the same, with a Ref Recordings record -but switch the leads at your cartridge -since we have already determined what sounds correct for CD. Again the leads will be left where they sound best. As far as Radio-don't worry about it. It is true that recordings are not all in correct phase, and I have also found that even radio stations are not all correctly set up, so it is not possible to have radio consistently correct-even if you use just one station. Others have commented on the benefit of a pre amp that will allow for switching phase; and it is quite a benefit particularly for fussy listeners of classical music where the recordings are usually much longer than rock,jazz,EZ listening. Please let me know if this is helpful: or not.
tbg- the industry standard is for things to be in phase and in polarity. it doesn't mean every recording is but the recordings most people prefer flipped aren't one way or another but in between and are preferred one way by a listener.
polarity is the correcting wiring. Don't confuse this with phase. Phase takes place between more than one source, like two microphones. if they are both in polrity, say pin 2 hot and correct they may be slightly out of phase with each other. when you start to correct an already mixed record with an absolute flip , you are usually choosing whatever sounds better, not correcting an absolute polarity issue.
Mothra, I don't think there is an industry standard. We have no way to know whether what people prefer in polarity is correct polarity, the best of quite mixed polarities on a given recording, or even incorrect polarity. This is the sad state of affairs given industry indifference concerning polarity.

Unfortunately, most of us lack the easy capability to invert polarity by means that do not degrade the signal.
At the very least, the initial attack of a kick drum from a kit should move the cone forward toward the listener. This is the way it is in the real world. This is not as easy to determine with other instruments that have more complex timbres. Also, microphones may or may not be transducing to an electrical signal in absolute polarity at all times. Ribbons work differently than dynamic configurations. Also, added ambience will often not be monitored in mono prior to mixdown in order to minimize phase cancellations and this too may negate any absolute polarity advantages.

Small studio live jazz recordings without much processing are the best way to reveal polarity issues. BUt that kick drum had better cause the cone to move forward toward me when I hear it and not away.
...and that's only if the kick was close miced, which it usually is.
well, the standard for wiring was pin 3 hot for a long time in europe and it was pin 2 hot in the US later. Now it is generally pin 2 hot. Studios tend to, and should pay attention to this meaning that the polarity should be correct from the microphone into the mic pre into the tape machine. After that you are talking about phase relationships which are far more complicated.
Stevecham, I appreciate your point; however where the mic for the drum is placed may be a confounding issue. Just a thought.