Absolute Polarity: Are you In or Out?

[Mike F]

Which configuration do you prefer? I find my 4425s sound more natural electrically Out but acoustically In phase, where:

Amplifier +/Positive/Red terminal > Speaker +/Positive/Red terminal would considered to be of Reversed absolute polarity
and
Amplifier +/Positive/Red terminal > Speaker -/Negative/Black terminal would be considered to be In absolute polarity

were a positive DC voltage applied to the +/Positive/Red terminal of a woofer would result in an inward cone motion, provided that your speaker system follows that wiring convention

Particularly in the first few octaves, the differences are most apperant with material that contains lot`s of low frequency percussive information, it just gels more coherently with the rest of the spectrum.
The effect is diminished the further up the frequency range you go, stereo imaging, instrument placements etc. dont seem to be affected much if at all.
It`s worth mentioning that there were no other polarity inversions further up stream in various gain stages, that was confirmed with my trusty SCV PC-80, but that might not be the same in your case.

If you havent yet experimented, I encourage you to give it a try, you may be pleasantly surprised by the results!

[Mr. Widget]

I used to have an Adcom preamp and CD player and one of them had a polarity choice on the remote... I don't remember if it was the pre or CD, but it was damned convenient to flip back and forth on the fly from my listening position. I was pretty convinced I heard a real difference between the two choices... since you never know which polarity convention a particular recording has used, you can't say that either position is always "absolute", but it was very interesting to flip back and forth.

After going through this a number of times with many recordings over a fairly long period of time, I ultimately decided that I couldn't come to any rock solid conclusions... I couldn't even say that a particular recording sounded best in position A or B all of the time. I ventually decided that absolute polarity wasn't something that I was sensitive to... kind of convenient really. ;)


Widget

[audiomagnate]

I think it depends upon which universe in which you exist, matter or anti-matter, right? Or is this a trick question? I would like the kick drum positive pulse to equal a positive pulse in my room.

[DavidF]

I think it depends upon which universe in which you exist, matter or anti-matter, right? Or is this a trick question? I would like the kick drum positive pulse to equal a positive pulse in my room.

So confusing, this issue. Another trick question. Does the kick drum, when struck, cause a compression or rarefaction waveform in the room?

[Allanvh5150]

So confusing, this issue. Another trick question. Does the kick drum, when struck, cause a compression or rarefaction waveform in the room?

Kick drum is the same as any other wave form. Frequency is between 50 and 70 hz but is very short lived so it seems more like a pulse. Phasing should not really make any difference appart from at the crossover frequency. Even if drivers are time aligned, by the time the sound reaches the listener, everything is out of phase anyway.

Allan.

[tom1040]

I used to have an Adcom preamp and CD player and one of them had a polarity choice on the remote... I don't remember if it was the pre or CD, but it was damned convenient to flip back and forth on the fly from my listening position. I was pretty convinced I heard a real difference between the two choices... since you never know which polarity convention a particular recording has used, you can't say that either position is always "absolute", but it was very interesting to flip back and forth.

After going through this a number of times with many recordings over a fairly long period of time, I ultimately decided that I couldn't come to any rock solid conclusions... I couldn't even say that a particular recording sounded best in position A or B all of the time. I ventually decided that absolute polarity wasn't something that I was sensitive to... kind of convenient really. ;)


Widget


My Marantz SA7S1 SACD player has an 'inverted Phase' button on the unit itself. Although I have yet to really sit down & try this out more than a couple of times, the OP question has me wondering about this. Mr Widget's response was my initial reaction to this feature. Perhaps I need to do some more listening with various recordings.:dont-know:

[Lee in Montreal]

Doesn't Bose pretend their Waveguide system sounds "better"? :D One listener may probably enjoy the special effect of sound being out of phase, but smoking a spliff before siting down for listening to music probably brings the same effect... ;) My point is that when the left source fights the right one, then all that comes out is a flat sound. You'll loosing your kick and the overall impact. If my system sounded "better" with one channel's polarity reversed, then I would check if all drivers are properly connected...

[1audiohack]

My question is if you could control it, why wouldn't you? I can and I do and yes, I sleep better at night.

[hjames]

Doesn't Bose pretend their Waveguide system sounds "better"? :D One listener may probably enjoy the special effect of sound being out of phase, but smoking a spliff before siting down for listening to music probably brings the same effect... ;) My point is that when the left source fights the right one, then all that comes out is a flat sound. You'll loosing your kick and the overall impact. If my system sounded "better" with one channel's polarity reversed, then I would check if all drivers are properly connected...

From what I am readying, it sounds like it flips polarity for both channels ...
Sound starts with drivers pull away instead of a push toward - or some such thing ...

Still sounds esoteric to me.

[Eaulive]

Aaaahhh, another really tricky subject, that I personally put in the same category as oxygen free monster cables and antivibration pads for MP3 players.

[Mr. Widget]

From what I am readying, it sounds like it flips polarity for both channels ...
Sound starts with drivers pull away instead of a push toward - or some such thing ...

Still sounds esoteric to me.The term "absolute" polarity is just that... the polarity of the recording and playback chain... i.e. when the drum was struck, the sound was initially captured by a mic with a positive electrical pulse... during the recording, mixing, mastering, storing, transferring, and eventual reproduction in your home, the polarity was changed many times... the idea is that it should be in the same polarity as it was originally created. I get that... can't say that I hear a consistent difference or "correctness".

Reversing the polarity of only one channel is plainly audible and is quite different.


Widget:

[Mike F]

Doesn't Bose pretend their Waveguide system sounds "better"? :D One listener may probably enjoy the special effect of sound being out of phase, but smoking a spliff before siting down for listening to music probably brings the same effect... ;) My point is that when the left source fights the right one, then all that comes out is a flat sound. You'll loosing your kick and the overall impact. If my system sounded "better" with one channel's polarity reversed, then I would check if all drivers are properly connected...

Messing with relative polarity is just plain retarded. I`ve seen it done with radio`s, tv`s and such marketed as a space enhancer or whatever but I find the effect most annoying.

[Allanvh5150]

The term "absolute" polarity is just that... the polarity of the recording and playback chain... i.e. when the drum was struck, the sound was initially captured by a mic with a positive electrical pulse... during the recording, mixing, mastering, storing, transferring, and eventual reproduction in your home, the polarity was changed many times... the idea is that it should be in the same polarity as it was originally created. I get that... can't say that I hear a consistent difference or "correctness".

Reversing the polarity of only one channel is plainly audible and is quite different.


Widget:

Hi Widget, Something else to make phasing with dums more interesting, depending on which side of the "skin" the Mic is placed the electrical pulse would be either positive or negative. But you are right in saying that the phasing is changed so many times along the way that no one knows how it is supposed to be.

Allan.

[Hoerninger]

Which configuration do you prefer?
I don't care.

A bit OT but in a live performance I do care for the same polarity of the sound of the natural speaker/singer and the sound of the PA.
____________
Peter

[rusty jefferson]

Absolute Phase




When a musician plays a note on the trumpet in Figure 1. air is forced from the trumpet first as a compression of the air followed by a reduction in air pressure called a rarefaction. The MIKE in the picture converts the compressions and rarefactions produced by the trumpet into an electrical voltage.


http://www.omegamikro.com/images/ap_f1_ip.jpg

The voltage is in absolute phase with the sound waves if a positive voltage corresponds to a compression and a negative voltage corresponds to a rarefaction. This voltage gets converted into pits (by the CD manufacturer) and when played back on your sound system will either reproduce the original note in the same absolute phase as the original, Figure 1., or in inverted phase with the original, Figure 2.

Why should absolute phase be obvious to the listener? I believe it has to do with rather recent research that shows that our inner ears’ hair cells are easier to bend in one direction than in the other. Prior research found no difference in the way we hear the absolute phase of pure tones so many in the audio business believed that the ear was not sensitive to absolute phase when listening to music or voice.


http://www.omegamikro.com/images/ap_f2_ip.jpg

Since many recording studios paid little attention to absolute phase it’s not unusual to encounter multi-miked recordings in which some of the instruments are in absolute phase and others are inverted, e.g., listen to the piano on the original release of track 1 of Miles Davis’ Kind Of Blue. The piano was recorded out of absolute phase and sounds obviously wrong (although beautifully played).

Fortunately, you can arrange your system to be sure a properly recorded source plays back through your speakers in absolute phase. All speaker manufactures color code their speaker terminals so that a positive-going voltage at its red or positive terminal will cause the speaker cone to move forward from its enclosure to create a compression.

To test that your system is in absolute phase, I recommend playing no more than a one-minute portion of a Mapleshade (or other CD where absolute phase has been correctly recorded) recording of a solo piano. Piano notes have a distinct attack and decay that we’re all pretty familiar with. When your sound system is in absolute phase the piano notes will sound sharp and clean. If in reverse phase the notes will sound almost backwards and slightly softer. If you want to reverse the phase of your system all you have to do is to reverse your speaker cables at the amplifiers. Please see Clark Johnsen’s ”the Wood Effect” for a more in-depth description of absolute phase and its history.




Link to the wood effect:
http://www.positive-feedback.com/Issue1/cjwoodeffect.htm (http://www.positive-feedback.com/Issue1/cjwoodeffect.htm)

[Robh3606]

It's a crock. If you are sitting 10ft away and then move to 15ft away you just changed the "absolute phase" of a live instrumnet being played in front of you in real time. So when you have someone playing an acoustic guitar in front of you does the realism change as you switch seats?? Sounds wrong or fake in row 3??

Rob:)

[1audiohack]

Where did we skip from polarity to phase? It's not the same thing.

[Allanvh5150]

Where did we skip from polarity to phase? It's not the same thing.

As it is an AC waveform you can not talk about polarity. DC sure, AC you should talk phase. The red and black terminals on speakers are not negative and positive per se, they only give an indication of phase.

Allan.

[1audiohack]

Very few waveforms generated by musical instruments look much like sinewave. Yes they are periodic and as such have equal energy above and below zero but take a scope shot of a drum where the lead looks much like an impulse with a very small time period and very large amplitude, for the sake of argument lets agree that this initial spike is posative, looking further in time one finds the decay energy is mostly below zero but the amplitude while varying in the negative, it's amplitude is significantly lower and therfore it's energy is dispersed over a much greater period of time.

As you know an impulse has a very wide frequency envelope hence the reason a kickdrum hits the tweeters with so much energy. This is an easy example to argue in the sense that if all the drivers reproducing the sound of the drum are not in polarity, they won't reproduce the sound coherantly as well as they could if they were in polarity and in time/phase. But we get away with a lot in the real world don't we.

For a much more complex sound consider a piano, a precussion and string instrument with the even order harmonics of strings and the odd order harmonics of solid rods, these are very complex wave forms and will tear apart speakers with poor crossovers and poor driver integration. The reason? The very wide range harmonics get seperated in time from the fundamentals and the sound gets decimated. Listen to piano on a pair of those old Yamaha NS10 studio monitors so may people love, they sound absolutely terrible to me.

Consider a familliar compression driver, with about 10 to 1 comp. ratio, do you believe the sound of the air being driven out of it through the phase plug by that big motor sounds exacty the same as the air being pushed back into it by atmospheric pressure? I have stated this before, if you switch polarity of a compression driver playing a saxaphone it sounds more like a clarinette when the driver polarity is inverted. Ironically the waveform looks like that, an inversion of one another. We have an alto sax, a clarinette, drums, bells, a trombone and other stuff in the house and it is great to have these references around. I say don't sweat what you can't hear, why trouble yourself. However I submit to you that in the pursuit of audio fidelity, it can make a difference, it can be masked by other issues and while not something that often makes you think damn! What's wrong?!? When it's right it does contribute in a most posative way.

[svollmer]

My preamp has a polarity switch that can be controlled by the remote allowing quick comparisons. I've done several unscientific experiments listening to all kinds of music with my eyes closed while switching and for whatever reason, I always, although very slightly, prefer it switched to reverse phase. Maybe one of my other components has its phased reversed and this "reverses the reverse." :dont-know:

I'm sure different recordings have different phasing because of the unknown recording chain, but in general, I prefer my system with the preamp reversed so I just leave it that way. Now I'll admit, this is a teeeeeeeny difference and I really don't hear much of a difference at all; but I just "like" it better that way.

When I play my drums, my bass drum (I don't "kick" any of my drums - sorry a pet peeve) pushes sound in a forward motion from the drum; it doesn't pull air in. The drummer might suck, but the bass drum doesn't. ;)

[rusty jefferson]

My preamp has a polarity switch that can be controlled by the remote allowing quick comparisons. I've done several unscientific experiments listening to all kinds of music with my eyes closed while switching and for whatever reason, I always, although very slightly, prefer it switched to reverse phase. Maybe one of my other components has its phased reversed and this "reverses the reverse." :dont-know:

I'm sure different recordings have different phasing because of the unknown recording chain, but in general, I prefer my system with the preamp reversed so I just leave it that way. Now I'll admit, this is a teeeeeeeny difference and I really don't hear much of a difference at all; but I just "like" it better that way.

When I play my drums, my bass drum (I don't "kick" any of my drums - sorry a pet peeve) pushes sound in a forward motion from the drum; it doesn't pull air in. The drummer might suck, but the bass drum doesn't. ;)


Many "higher end" preamps, (and some amps) have a normal output of "inverted phase". If you don't have an original manual, google the model # with "inverted phase" and see what comes up. I've walked into several listening sessions that folks didn't know it and had the amp/speakers wired backwards. Could you tell walking into the room? No, but with careful listening to high quality recordings of piano and horns in particular, you can tell. You probably won't notice on multi track recordings from the 70s-80s as the instruments have been eq'ed, compressed, time delayed, or whatever, and don't have their natural sound.

[Lee in Montreal]

Okay then. If the piano mike was recorded in reverse and the 10 mikes for the drums, congas, vocals, bass, strings etc were recorded properly. So to fix the piano, one must reverse the polarity and sacrifice the 10 other instruments... hmmm ;)

[Robh3606]

Where did we skip from polarity to phase? It's not the same thing.



Well depends on how you look at it. The difference between polarities is 180 degrees of phase. That's the only difference. I tend to lump them polarity, distance and so on as phase changes which indeed they are. I wrote that guick last night and for one thing I should not have said that you change absolute phase when you move. You don't change absolute phase you change relative phase . Phase is a constanly changing and the rotations increase with frequency so it's mess to keep track of. The only difference between the two waveforms would be is that they are mirror images.

Rob:)

[DavidF]

So if we could agree that absolute polarity is preferred how do we achieve it, practically speaking? I would be disqualified in this exercise right away since I am listening to a 4-way speaker system with odd and even order passive topologies with all kinds of absolute and nonabsolute phase differences and compensations. Instead of either/or phase inverting switch my need is for a phase compensator covering 360 degrees, not just 180. But I may only reach absolute in a narrow range of the audio spectrum. Really what we would need is a digital solution that can constantly measures and adjusts for changes in phase going up and down the spectrum as well as any hardware induced and distortion induced phase differences. Then again would such a device kill the argument only to introduce a completely different argument about the side effects of the solution, I wonder?

[Mr. Widget]

I would be disqualified in this exercise right away since I am listening to a 4-way speaker system with odd and even order passive topologies with all kinds of absolute and nonabsolute phase differences and compensations.Now that is an interesting and possibly important distinction. Along wit the earlier posting discussing Mapleshade and others who make a point of preserving absolute polarity in their recordings.

To be sure, I don't remember what speakers I had during my Adcom days when I played with the polarity reversing switch... and I don't remember if I tried any simply mic'd recordings. I do think that the best test of the absolute audibility of absolute polarity would be with simple recordings and the use of single driver "full range" loudspeakers.

I may set up an experiment and play around with this at some point I'd be curious just how audible it actually is under idealized conditions.


Widget

[grumpy]

fodder:

http://books.google.com/books?id=Qpmi4ia2nhcC&pg=PA23&lpg=PA23&dq=compression+rarefaction+impulse+audibility&source=bl&ots=hBy7h9KD_n&sig=YOmy-ZjRjjzhqZg4u2VlqYDAOa4&hl=en&sa=X&ei=OOguT_7VMuPYiQKLps3cCg&ved=0CEMQ6AEwAw#v=onepage&q=compression%20rarefaction%20impulse%20audibility&f=false

[Eaulive]

Where did we skip from polarity to phase? It's not the same thing.

I was going to say the same thing, and I crack myself up everytime I hear the term "absolute phase", :banghead:

[Eaulive]

As it is an AC waveform you can not talk about polarity. DC sure, AC you should talk phase. The red and black terminals on speakers are not negative and positive per se, they only give an indication of phase.

Allan.

You are wrong, an AC signal has a polarity. Imagine a signal that is a sinewave in the bottom part and square in the top part. It's easy to see that this pattern will remain the same whatever distance you are placed from the source. However if you inverse the polarity, you just swapped the square part to the bottom and the sine part to the top.
That's the system used by the speaker polarity checkers, no matter how far you are, the pattern will never change except if the polarity is reversed.

Now, can you hear a difference? Honestly I can't. The little polarity checker box can, however :D

Phase, at the risk of repeating myself, is the relation in time between TWO OR MORE signals. this term is completely irrelevant whan talking about one source or signal.
Two signals of opposite polarity will never be really in phase, however you can have two signals of the same polarity out of phase.

[4343]

...

When I play my drums, my bass drum (I don't "kick" any of my drums - sorry a pet peeve) pushes sound in a forward motion from the drum; it doesn't pull air in. The drummer might suck, but the bass drum doesn't. ;)


That would depend on which side of the drum you are on, wouldn't it? On the pedal side, the initial attack is a rarefication. So for drummers, the bass drum does suck. (See trick question earlier in this thread...)


...All speaker manufactures color code their speaker terminals so that a positive-going voltage at its red or positive terminal will cause the speaker cone to move forward from its enclosure to create a compression. ...

Funny, none of my vintage JBL's do that.

[Eaulive]

So if we could agree that absolute polarity is preferred how do we achieve it, practically speaking? I would be disqualified in this exercise right away since I am listening to a 4-way speaker system with odd and even order passive topologies with all kinds of absolute and nonabsolute phase differences and compensations. Instead of either/or phase inverting switch my need is for a phase compensator covering 360 degrees, not just 180. But I may only reach absolute in a narrow range of the audio spectrum. Really what we would need is a digital solution that can constantly measures and adjusts for changes in phase going up and down the spectrum as well as any hardware induced and distortion induced phase differences. Then again would such a device kill the argument only to introduce a completely different argument about the side effects of the solution, I wonder?

The thing is, you can have crossovers, delays and a lot of things that will affect phase without inverting polarity. However it's common practice for speaker manufacturers to run a driver 180º out of phase by reversing polarity, for example, a midrange driver could be wired with the opposite polarity in order to maintain phase coherence between woofer and tweeter at each crossover point.
Doing so the phase is maintained, but the actual absolute polarity of this driver is reversed.

I would volunteer that in those systems, the phase incoherence created by a "properly" wired driver is much more audible than a polarity reversal and proper phase.

[Eaulive]

Consider a familliar compression driver, with about 10 to 1 comp. ratio, do you believe the sound of the air being driven out of it through the phase plug by that big motor sounds exacty the same as the air being pushed back into it by atmospheric pressure? I have stated this before, if you switch polarity of a compression driver playing a saxaphone it sounds more like a clarinette when the driver polarity is inverted. Ironically the waveform looks like that, an inversion of one another. We have an alto sax, a clarinette, drums, bells, a trombone and other stuff in the house and it is great to have these references around. I say don't sweat what you can't hear, why trouble yourself. However I submit to you that in the pursuit of audio fidelity, it can make a difference, it can be masked by other issues and while not something that often makes you think damn! What's wrong?!? When it's right it does contribute in a most posative way.

Interesting, we discussed about this in the past.
My question is, why do you hear a difference? Because of the polarity reversal or beause the driver is not linear and doesn't treat the compression and rarefaction waves the same way?
If you have a driver that has exactly the same behaviour in compression and rarefaction, would you still hear a difference? If you could invert perfectly the waveform that comes out of the saxophone, right there in the room, could you hear a difference?

In the case of a sine wave, even if the comp. driver is not consistent with its "push/pull" wavefronts, reversing polarity will have no effect, but that doesn't mean the waveform is not distorded.

Food for thought :D

[1audiohack]

Well you know what they say about audio, that it's all in your head.

I sat down with the laptop plugged into the DBX4800 as to be able to switch polarity from the chair this morning before work and cannot discern a difference on the sax track on the Alan Parsons Sound Check CD when flipping polarity. I do have a mild head cold however.

Two things have changed since I truly believed I could hear a difference, I went from two DBX 260's in dual mono configuration to a single DBX 4800 and from JBL D8R2450SL diaphragms to Truextent Be4008's in the 2446's. If i were to guess, I'm betting on the driver improvement.

I tend to only devote time and study to audible issues, if I can't hear it I don't go looking for it so maybe I recant and move on.

As usual, I refuse to be held to anything I wrote more than couple of years ago as I would like to think things are improving and I am learning. :p

[DavidF]

....
Phase, at the risk of repeating myself, is the relation in time between TWO OR MORE signals. this term is completely irrelevant whan talking about one source or signal.


That would seem to make the importance of phase as it relates to multiway speakers a moot point. :confused: The answer is likely that the crossover, driver separation, etc all interact and introduce false phase differences in the original signal. Ideally we would want the output signal from the many drivers phase -realigned, -retimed, -regrouped, -something, so that it is again one signal in the same (struggling for a word other than absolute, here, help me out!) pure phase as the original.


Back on point of polarity, is a 45-90 degree phase offset-as evident with odd order topologies-laying outside the bandpass going to blunt any audible effect of absolute polarity?

[DavidF]

"...Consider a familliar compression driver, with about 10 to 1 comp. ratio, do you believe the sound of the air being driven out of it through the phase plug by that big motor sounds exacty the same as the air being pushed back into it by atmospheric pressure? I have stated this before, if you switch polarity of a compression driver playing a saxaphone it sounds more like a clarinette when the driver polarity is inverted. .."

Scoundrel, now you are inserting a horn section and drums into the mix:crying:. Can we expect horn-loaded compression drivers to function properly in "reverse" compared to a cone driver? You invert the impedance/pressure transformation effect of the horn loading, and such.