Invert ?

This is phase inversion explained. You will not damage anything using it. Some recordings are out of phase.

While it is very common to call this "phase" inversion, calling it polarity inversion makes more sense to me but, that is a minor point. The first thing to be aware of is that not everyone is sensitive to "absolute" polarity inversion which is, both channels being inverted at the same time. I know a couple of people that say they don't hear any difference. There is also the not common issue of "relative" polarity inversion which is, just one channel being inverted, usually by an incorrectly connected speaker wire on one channel at either the amp or the speaker (red to black and black to red). I think that most people can hear that something is wrong when relative inversion exists in a given system. 

Paul's explanation is a bit on the technical side. Here's what I perceive when comparing correct polarity to incorrect polarity The sound with correct polarity will project outward toward the listener and there will be more space and air around the sounds and voices. Incorrect polarity will move the soundstage back a little and will flatten the soundstage as well. There will be less space and air around the sounds. In my experience the effects of correct/incorrect polarity will vary with speaker design in particular, speaker placement in the room, and all of the other variables with room dimensions, wall treatments, etc.

If you don't pick up on the differences at first, pay attention to how the bass sounds and also high sounds such as high hat cymbals as you try each switch position.

Yes, as yogiboy said, some recordings are polarity inverted.

@yogiboy  i watched the video. TY.  But  As Denzel Washington said in the movie Philadelphia “ Explain this to me like I’m a 2 yr old because there’s an element to this thing I can’t get through my thick head. 🤦‍♂️🤷‍♂️

When an instrument first emits a sound, the wave starts as a positive pressure that rises and falls followed by a negative pressure (lower than the initial static pressure before the sound wave arrived).  Ideally, the speaker should follow the same pattern as the original sound wave.  But, in the many steps of the recording and playback process, the correct order of compress first (or vice versa) followed by negative pressure may be reversed.  Since, almost all recordings involve multiple microphones and line feeds, any one such feed could be inverted, so the effects of inverting polarity in your linestage may be very subtle and one position may not clearly be superior to another even when differences can be heard.

Because your gear itself can be inverting phase, you may not know whether or not your system is generally inverting phase.  The effect of such inversion is subtle enough that it is not easy to make a reliable comparison by switching around the speaker connection, and a more instantaneous comparison via an inversion switch is helpful.

Why don’t most better gear offer this switch?  This capability involves adding another active stage that theoretically degrades the signal. 

@larryi Nice explanation.  Thanks!

@mwh777  +1. Great explanation

Pual Mc educated me decades ago, except he incorrectly calls Polarity Phase, which he admitted. I  first learned about it when I had Genesis Vs with powered sub, which had RC of volume and Polarity. I discovered the biggest offender was bass Polarity. If you're looking for a sub IMO, best is one with RC of Polarity. That said Polarity/phase on a remote preamp or integrated is very meaningful to my ears

hth

Play some music you know that has good bass (make sure your speaker cables are connected correctly). Flip the switch and listen for any change to the bass. whichever position has the most bass is the correct polarity. 

@ everyone. Ty for all your explanations. Very interesting. 

@larryi +2 Thanks!

Mike

@tattooedtrackman,

See article below:

Mike

https://www.justmastering.com/article-phase-and-polarity.php

You should get one of these to stop yourself from going crazy listening for the effect

Years ago I had a preamp with a phase inverter button on the remote.  It didn't take but a few pushes now and then to realize I couldn't hear any difference one way or the other.  

I believe I read somewhere that there is a listing of songs, albums, whatever, that lists those that were recorded ending up with the phase inverted.

I also believe that I read somewhere that even different songs on a single CD, LP, can end up with some correct and others with inverted phase.

I've got Herron Audio line stage preamp and phono preamp. He's got polarity rocker switches on the backs of both; he recommends trying them each way but says a lot of people can't hear any difference, and I could not.

He's also got an 'Invert' on the remote and on the line stage preamp, and that does have the effect of switching the wires on the back of one speaker, and makes a huge difference. When in phase, there's a well-defined center image - when out of phase, there is not and the bass (and most everything else) is weaker.

Chesky has a test CD with sample jazz tracks from their catalogue.  One of the teat track offers two pieces of music where a track is played in normal polarity and then in inverted polarity.  With such side-by-side tracks you can see for yourself if polarity matters.

Speaker design plays a big role in whether polarity is heard.  Designs that attempt to preserve phase relationship and timing of arrivals of sound from each driver will make polarity more obvious.  If you cannot hear polarity change because your speakers muck up phase/timing relationships, fear not, many very good speakers are not good at this test.

Phase inversion drives me crazy.  I own a lot of Conrad Johnson equipment.  

Some components phase invert, others don't.  

I've recently installed a Schiit phono stage.  I asked their online AI, and get a 'maybe yes or no'...so much for AI.  No reply from a human as of yet...  It makes a difference! 

Your switch gives you one phase inversion, if you wish to use it!

If anyone determines their absolute phase (total system) is not of the correct polarity, and have no switching to use in the system, simply reverse the leads on the speaker cables at the speakers. 

Thanks everyone for all these great explanations. One question   How do u know if a recording is out of phase? How often does this happen in a recording? What is the best way to tell ? 🤷‍♂️

@OP, there's no way to tell except by listening. MWH777's post explains it well. To the extent that it is audible, the effect is likely to be more obvious by playing some simply mic'd recordings .

 You can hear it. Fortunately, when two signals are badly out of phase, it’s easy to hear. When two similar tracks are mixed, they can sound thinner, tinnier, or harsher, indicating that they have a phase problem.

@yogiboy  Thanks. That makes sense. 

To get a baseline of what phase inversion sounds like, push the invert switch on your preamp for any song you are currently playing and listen if you hear a difference.  If you do, you will know what to listen for in inverted tracks.

That invert switch is a nice feature. My gear does not have that so if I wanted to check out the correct phase I would have to reverse the pos and neg on both speakers. I would have to shut off my amp every time and that’s just not worth the inconvenience of doing that!!

There was a booklet that made the rounds several decades ago, called The Wood Effect. Who knows, it may still be in print, or available through an online book vendor. The topic was absolute phase- and a number of examples were given as I recall. But, as another member here astutely pointed out, most stuff is multi-tracked, often recorded and mixed in various studios, whether all that stuff when mixed down is in the same phase was pretty doubtful. I do remember one example being that old warhorse- Dusty's Look of Love. Was the horn blowing or sucking? (rhetorical music question, not a value judgment). It's one of those quandaries that is probably impossible to solve. 

However, in previous systems, there seemed to be only modest effect by hitting the invert switch. In my current system, I leave it non-inverted and if I hit invert, it does not sound right. I'm not sure what that means, but I just don't mess with it. 

The booklet The Wood Effect was written by Clark Johnsen. If you do a search you will find a number of sources that discuss this topic. I had met Clark a number of times at audio shows as he made it a point of coming to our room to hang out. He also always made a point of saying that if your ears were not sensitive to absolute phase in recordings that you should consider yourself very fortunate.

I responded to Clark when he was writing for Positive Feedback. I believe our conversations were about polarity. Eventually we became friends. He would come to Ft Lauderdale and stay at my house: GOOD TIMES. I have several copies of The Wood Effect

Clark Johnsen has written a lot of pieces about absolute phase and polarity. He was a lot of fun to hang out with at the Las Vegas shows and we often had dinner with him and a few other industry folks, including the late Arthur Loesch, at a local Las Vegas restaurant. Sad that he is no longer with us but this thread has motivated me to seek out some of his work.

@clio09- I did a cursory search- the booklet-- which was around 99 pages, now sells for astronomical numbers as an out of print publication. There are other things, though- listening tests, which I believe were done after the booklet, are in the AES archive-- free to members, otherwise a 30+ dollar monograph. I think there were a few articles, perhaps interviews as well, in the legacy press. Pretty easy to find on an open web search.

After I posted initially, about why my current system sounds terrible in invert mode, I realized that I had wired the system to run the midrange horn directly from my Lamm SETs(no Xover either), then jumpered the tweeters and woofers out of phase to the mid horn. The additional sub woofers are also dialed in to adjust delay/phase.

So, the system coheres as set up, but invert-- not good sounding. 

Beyond the recording polarity ( which unless you make your own references ( hint ), polarity and achievement of absolute polarity is math for the active electrical components ( do the invert or not ) AND importantly but beyond frequently ignored, how do your speakers do on the impulse test ?
 

@clio09 has it correct, there are many sonic curse or, i prefer blessings… can you hear polarity, pitch, phase, time…. or ? 

The wood reference fascinating and this thread excellent….. audiogon at it’s best….

also… the Herron gear has an AC inversion switch…. plainly audible… just to add to the myrid possibilities of neurotic listening….