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Polarity mystery: Can you help me solve it?

THE BACKGROUND: My speakers are Focal 1007be. They have a Linkwitz-Riley crossover with a 36 dB per octave slope. Because of that, the two drivers are wired with opposite polarity: the woofers are positive, the tweeters are negative.

WHAT I DID: At the advice of a friend with the same speakers, I inverted the polarity of the drivers, by simply reversing the red and black speaker wire leads to the terminals of both speakers, so that the speakers are still in phase with each other, but now the woofers are negative polarity and the tweeters are positive polarity.

WHAT HAPPENED: To my surprise, the sound improved! Specifically, image focus improved. The improvement can't be attributed to the preservation of the absolute phase of the recording, since the improvement was the same for many different recordings (some of which, presumably, preserve absolute phase, while others do not). And the improvement can't be attributed to the speakers being wired incorrectly at the factory, since the friend who suggested that I try this experiment owns the same speakers and experienced the exact same result. So I don't know what to attribute the improvement to.

Can anyone help with this mystery?
bryoncunningham
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almarg
9,670 posts
 
Hi Bryon,

OK, so much for that theory. Well, I'm left at a total loss in trying to suggest an explanation.

I can't envision how your observations could be related to interaction with room effects, as has been suggested. The effects of inverting the signal polarity into the speakers would be undone by either the polarity inversion or the lack of polarity inversion of some of the recordings you listened to, relative to the effects on other recordings that presumably have the opposite polarities. And add to that the fact that it is meaningless to speak of absolute phase preservation or polarity inversion on many recordings, because they comprise a combination of various sounds and instruments that may be mixed together with random phasing. All of which makes the consistency of your observations across a variety of recordings befuddling.

Best regards,
-- Al
bryoncunningham OP
890 posts
 
Al - I agree, it is befuddling. I would be inclined to conclude that I am crazy, if it were not for the fact that my friend with the same speakers experienced the same thing. Perhaps it is Folie à deux!
bryoncunningham OP
890 posts
 
Another thought: I wonder if it has something to do with how the sound from the tweeter and woofer "sums" at a particular listening distance.
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onhwy61
5,229 posts
 
I looked at your system page, but I don't see any pictures of the room. Does your room contain many highly reflective surfaces? If so, from looking at the Stereophile measurements, the reversing of the driver polarity could result in a mid-treble suckout which would have many of the sonic effects you descibe. Stereophile concludes that the speaker is best suited for a large, well damped room. If that's not a description of your room, then intentionally having the speaker malfunction might actual work better.
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almarg
9,670 posts
 
Perhaps it is Folie à deux!
LOL!
I wonder if it has something to do with how the sound from the tweeter and woofer "sums" at a particular listening distance.
Does your room contain many highly reflective surfaces? If so, from looking at the Stereophile measurements, the reversing of the driver polarity could result in a mid-treble suckout which would have many of the sonic effects you descibe.
It seems to me, as I indicated earlier, that while all of these are factors that may be relevant in a general sense to the sonic characteristics of the system, they are inapplicable to the observations Bryon has stated. The reason being that they would not have effects which are simultaneously consistent both with connection polarity and across recordings that maintain absolute phase, that have inverted absolute phase, and that have randomly mixed phases.

It seems to me that that observation, of consistency across many recordings, shoots down all of the theories that have been offered, aside from mine which has been shot down in other ways.

Best regards,
-- Al
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