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Reverse polarity on speakers (not out of phase)

I'm a little surprised at how people think they can tell the difference between positive and negative phase. This is not the same as the question whether there might be a little glitch when you press the phase button (physical or virtual). Most of the time you are hearing successive cycles. How on earth is your ear supposed to know that it's pulling when it's supposed to be pushing? It's not like you're hearing iambs or trochees. If this were a big deal I don't think phase inverting amps and Dacs would be made.

I've tried the positive and negative phase tracks on the first stereophile test cd. Nothing I can tell.
 
Sue Pertwee-Tyr said:
And therefore, presumably, if a desk has the facility to sort out this chaos, then it matters that it is sorted out. I can't see the manufacturers of mixing desks adding an unnecessary frippery if it achieves nothing in the overall scheme of things.
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I assume it's so you can get different channels in phase, not so you can get the whole thing in positive or negative phase.
 
Sue Pertwee-Tyr said:
And therefore, presumably, if a desk has the facility to sort out this chaos, then it matters that it is sorted out. I can't see the manufacturers of mixing desks adding an unnecessary frippery if it achieves nothing in the overall scheme of things.
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Yes, because when mixing you are dealing with multiple sources, so sometimes phase is an issue. The classic example is if you mic the top of the snare drum and the bottom of the snare drum - apparently it is generally the case that you invert the phase of either (doesn't matter which) mic channel.

With digital plugins you can adjust the phase in more subtle increments, but I don't know how widespread that is. It is certainly the case that any pro desk will have a 'phase invert' button on every channel.
 
Klyde said:
Some LP/CD's are recorded in reversed phase and sound much better when you change the polarity. One example I know of is Lou Reed's wonderful New York album (1989).
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Have you got any more evidence/links re. this?
 
tedmanzie said:
Have you got any more evidence/links re. this?
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No, I'm afraid not, but they must be countless. If you're listening to a CD that sounds a bit bleak and shrill, reverse the phase and hear what it does? Don't forget to change back:).

Regards, Klyde
 
Klyde said:
No, I'm afraid not, but they must be countless. If you're listening to a CD that sounds a bit bleak and shrill, reverse the phase and hear what it does? Don't forget to change back:).

Regards, Klyde
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How are you reversing the phase?

I just did a quick test (using the iTunes purchased Lou Reed Romeo Had Juliette from the New York album) and there is no difference - well none that I can hear and I can't see technically why I should expect a difference. I can only think you are doing something other than inverting the phase?
 
Speakers don't "blow" or "suck", they vibrate. When a drum is hit, the cone doesn't pop forwards then backward, it just vibrates at the appropriate amplitude and frequency - whether the first movement of the cone is forwards or backwards is pure chance. I can't see how absolute phase change can make any difference at all. Its comparable to alternating current, there is no absolute polarity (the difference between live and neutral is only a matter of safety earth arrangements).
 
Turns out that the speaker terminals on a NAP200 are reversed compared to a nait XS so I unwittingly had my speakers out of absolute phase until my dealer came out to swap my preamp. Can't say I noticed a difference but then it did take over an hour to do the change of components and changing the speaker plugs around, plus the preamp was brand new.
 
AndrewM said:
Speakers don't "blow" or "suck", they vibrate. When a drum is hit, the cone doesn't pop forwards then backward, it just vibrates at the appropriate amplitude and frequency - whether the first movement of the cone is forwards or backwards is pure chance. I can't see how absolute phase change can make any difference at all. Its comparable to alternating current, there is no absolute polarity (the difference between live and neutral is only a matter of safety earth arrangements).
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I'm afraid that's untrue. The only time I have heard phase reversal was with exactly that. After messing around with connections one day, something sounded off with a kick drum piece that I had just been listening to. After checking everything I could think of, I discovered I had reversed the speaker connections. Putting them back restored the "slam". I tried both ways again and it was repeatable. This was with the original Heybrook HB3s, sealed boxes with good transient response. That's the only time I have heard it, and no, it wasn't expectation bias as it was a complete surprise and took some time to track down.
So I have to disagree with you, based on my own experience.
 
tedmanzie said:
Yes, because when mixing you are dealing with multiple sources, so sometimes phase is an issue. The classic example is if you mic the top of the snare drum and the bottom of the snare drum - apparently it is generally the case that you invert the phase of either (doesn't matter which) mic channel.

With digital plugins you can adjust the phase in more subtle increments, but I don't know how widespread that is. It is certainly the case that any pro desk will have a 'phase invert' button on every channel.
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The button inverts polarity. Phase and polarity are not the same thing.
 
tyranniux42 said:
Turns out that the speaker terminals on a NAP200 are reversed compared to a nait XS so I unwittingly had my speakers out of absolute phase until my dealer came out to swap my preamp. Can't say I noticed a difference but then it did take over an hour to do the change of components and changing the speaker plugs around, plus the preamp was brand new.
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you should be able to hear if one channel (speaker) is out of phase - you get a very thin and artificially 'wide' sound with light bass.
 
AndrewM said:
Its comparable to alternating current, there is no absolute polarity
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Music waveforms often are asymmetic, and thus not comparable to mains AC. Absolute polarity exists. Whether it is relevant to music listening is something else, though.
 
Yank said:
The button inverts polarity. Phase and polarity are not the same thing.
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Thanks for the correction.


[edit] but the test i did was inverting the phase (with software) and I couldn't detect a difference. Where do you stand on this?

[edit 2!] if you swap the red/black in both speakers are you inverting the polarity or the phase?
 
Phase includes time.

In a conventional system: positive voltage drives the speaker forward, positive displacement, and negative voltage does the reverse. If I delay the signal by a suitable amount of time then I can arrange for the speaker to move in phase with one of opposite polarity, but I have not changed the fact that it still moves forward with positive voltage. Reversing the polarity does not delay the signal, it makes the speaker move backwards, negative displacement, in response to a positive voltage.

Polarity is independent of time.
 
dweezil said:
Definitely a slight change on my cdp when you invert absolute phase. It's easy to check as there's a little button for that.
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Which CDP is that please? My simple Naim CD3 shows up absolute phase issues. My CDX2 seems to process out the problem, but smudges the sound slightly. I would love to have a polarity reverse button on a CD player, or even a DAC if I were to go for a CD transport.
 
Werner said:
Music waveforms often are asymmetic, and thus not comparable to mains AC. Absolute polarity exists. Whether is it relevant to music listening is something else, though.
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Well I agree polarity does in the sense that (+) makes the cone move in one direction and (-) the other, but it's a zero sum game, the cone moves the same forwards and backwards and the net dc current should be zero. A thwack of a drum stick is a pulse of multiple soundwaves not a single out/in movement of the cone, so I still contend that there should be no theoretical difference.

Just thinking out loud, if the system exhibits a small amount of dc offset current, could that so to speak tension the cone slightly in the direction of the offset, and change the sound slightly? Only a thought.
 
adamdea said:
If it does matter then it seems puzzling to me that DEQX go to all the trouble of correcting for the room, but stupidily leave their impulse response upside down.
http://www.stereophile.com/content/allnic-d-5000-dht-da-processor-measurements-0#pk43qR3m63Ujgjjk.97
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If you stupidly read the comments beneath the article:
There is a simple software switch that allows each of the four outputs (2 x main speakers and 1 or 2 optional subwoofers) to be individually phase inverted and auditioned in real-time.
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