Polarity mystery: Can you help me solve it?

Al/Bob - I could not locate my meter, so I asked my friend with the same speakers (and same observations) to test his speakers. His result: 2mV. So I guess that's not the solution to the mystery.

Thanks for the responses so far.

Gregm - Yes, the soundstage does seem a little deeper. But the more obvious improvement is that images are more focused. Your theory that the improvement is attributable to a room interaction was my first thought, but I don't know exactly what acoustical effect would account for it. Any idea?

Dopogue - I don't believe that the improvement is attributable to preserving the absolute phase of the recording, because the improvement is the same across a wide range of recordings.

Jea48 - Thanks for describing that method of checking the drivers. The fact that the tweeters and woofers are wired with opposite polarity is confirmed in Stereophile's measurements of the Focal 1007be, and from what I understand, that is common practice with a Linkwitz-Riley crossover with a 36 dB slope, as described here. Also, I am positive the two speakers are in phase with each other, as I have used a test disc with in-phase/out-of-phase tracks to confirm it.

Almarg - That is a very interesting theory, and certainly would never have occurred to me. In answer to your question, my friend with the same speakers does not have similar electronics. He is using an Ayre dac, a Vincent preamp, and a Parasound Halo amp. How would I know if my system had a DC offset?

Al - I believe I have a digital multimeter around here somewhere. I will look for it and report back my findings. Thanks!

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!

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.

Onhwy61 - No, my room does not have many highly reflective surfaces. It has a thick rug over a wood floor and 2" acoustical foam over a large area on the ceiling. Both side walls and the wall behind the speakers contain diffusion. Also, the room is not particularly small - it is 14x17x8.

However, there is something implied in your theory that seems plausible to me, namely, that somehow the crossover design could be relevant to my (and my friend's) findings.

Al - Assuming that the improvement I experienced really is constant across all recordings, regardless of their polarity, then surely we are right to conclude, as you and I both have, that the ABSOLUTE polarity of the recordings is irrelevant to the issue. But does it follow from that, that the RELATIVE polarity of the tweeter/woofer is irrelevant to the issue? I'm getting a little lost in the how that inference works.

BTW, I don't know if it's relevant, but the two drivers are not on the same plane. The woofer is recessed in the speaker cabinet, so that its center is slightly farther from the listener than the tweeter.

Jea48 - No, the two speakers are in phase with each other. And no, the woofer does not produce less bass. I believe you are confusing the following:

(1) The ABSOLUTE polarity of a recording - positive or negative.
(2) The RELATIVE polarity of a component - preserving or inverting.
(3) The RELATIVE polarity of the system - preserving or inverting.

Re: (1) The ABSOLUTE polarity of a recording refers to whether or not the waveforms represented in the recording correspond to the waveforms of the sound waves created by the real musical event. In recordings with POSITIVE absolute polarity, a COMPRESSION wave at the microphone corresponds to a COMPRESSION wave represented on the recording, while a RAREFACTION wave at the microphone corresponds to a RAREFACTION wave represented on the recording. In recordings with NEGATIVE absolute polarity, a COMPRESSION wave at the microphone corresponds to a RAREFACTION wave represented on the recording, and a RAREFACTION wave at the microphone corresponds to a COMPRESSION wave represented on the recording.

Re: (2). The RELATIVE polarity of a COMPONENT refers to whether the component preserves or inverts the polarity that it receives at its input. By reversing the speaker cable leads to my speaker terminals, I have changed the RELATIVE polarity of the speakers, that is to say, RELATIVE TO THE SIGNAL BEING SENT FROM THE AMPLIFIER. But because I reversed the leads to BOTH speakers, they are still in phase RELATIVE TO EACH OTHER. That is why I did not experience a diminishment of bass due to cancellation.

Re: (3) The RELATIVE polarity of a SYSTEM refers to whether the playback system, taken as a whole, preserves or inverts the polarity of the recording. A POLARITY-PRESERVING system will preserve the absolute polarity of recordings. A POLARITY-INVERTING system will invert the absolute polarity of recordings. When you put this together with (1), i.e., the fact that some recordings have POSITIVE absolute polarity and some have NEGATIVE absolute polarity, you get the following result: A POLARITY-PRESERVING playback system will preserve the "polarity" of the original event (i.e. compression=compression/rarefaction=rarefaction) ONLY WHEN the absolute polarity of the recording is POSITIVE. A POLARITY-INVERTING system will preserve the "polarity" of the original event ONLY WHEN the absolute polarity of the recording is NEGATIVE.

Al will correct me if I got any of this wrong.

Apologies if I'm telling you things you already know.

If you were to reverse the speaker connections, that ENTIRE waveform (including the initially negative-going tweeter output and the initially positive-going woofer output) would be inverted.

Ahhh! Now I get it, Al. The sentence above is what made it click for me. And yes, that does clarify your befuddlement, and it intensifies mine!

I was not saying the two box speakers were out of phase with each other, they are not. I was saying the two drivers housed inside each box speaker are wired out of phase with respect to one another.

Jea48 - Sorry, I misunderstood you. You are correct - the tweeter and the woofer, in each speaker, are wired with opposite polarity. This is common practice with a Linkwitz-Riley crossover with a 36 dB slope, as described here. As Al pointed out in his last post, the inversion is necessary to provide a flat frequency response.

By chance have you listened to the Focal 1007be speakers, wired both ways, with the JL Audio Fathom F113 sub turned off?

Yes, I have. The results are the same. So I don't believe the sub is a factor. And the sub polarity is the same as the woofers on the mains (both negative). I switched the sub polarity at the same time I switched the speaker cable leads to the mains, changing them both from positive to negative. Now that the woofers on the mains are negative polarity, failing to change the sub to negative polarity results, as you would expect, in a significant diminishment of bass due to cancellation. But I have not been listening to it that way, so that is also not a factor.

If you want to get a better idea what's going on, then at some point, after getting completely used to the way things are now . . . you need to put the connections back the way they were originally, and leave it that way long enough to form some new impressions all over again. The perceived change in sound should then of course be the opposite of what you first experienced. This is an important step - it will help rule out side-effects from the dismantling (i.e. tightening up the speaker drivers, refreshing connections), as well as confirm again that you're hearing what you think you're hearing.

This is a good suggestion, Kirkus.

...then the most likely explanation is that the loudspeakers' drivers/cabinet and crossover interact with each other differently when the phase is inverted...

This was my original theory. But I thought that Al just explained how any improvement due to driver/crossover/cabinet interaction would only apply to recordings with a particular absolute polarity, positive or negative. But the improvements I've experienced seem to be constant regardless of the absolute polarity of the recording. Does that refute the driver/crossover/cabinet interaction theory? Now I'm confused again!

So I'm guessing that in your case, where you have strong speaker magnets and a complex crossover, all stuck together in a small loudspeaker, that by reversing the driver lead phasing you're changing the electromagnetic interaction between all of thse components.

Fascinating. But would this effect be constant across all recordings with different absolute polarities?

my assumption was that you removed the woofers and tweeters from your loudspeaker cabinets, reversed the wiring on each of the drivers, and put the speakers back together. Is this correct?

No. I'm sorry that wasn't clear from the OP. I have done nothing to the speakers internally. I have simply swapped the speaker cables connections from the amp. In the OP, I said "speaker wire leads," which I now see is ambiguous. I should have said, "speaker CABLE leads." Sorry for the misunderstanding, everyone.

When I said that I "inverted the polarity of the drivers," I was referring to the fact that the woofer is wired positive and the tweeter is wired negative, and that, by reversing the speaker cable connections, I changed the woofer to negative and the tweeter to positive.

Kirkus - In light of this information, does your initial crossover/driver/cabinet theory still apply?

- In your room, with your system, and with your program material, reversal of absolute phase make enough of a difference enough of the time, in the right way, to be perceived as an improvement.

This explanation is looking more and more likely. I hope I have not been wasting everyone's time with what is nothing more than a psychological phenomenon!

In any event, thank you for your thoughtful effort to help me diagnose the issue. Likewise for all other posters.

Kirkus - What do you think of Al's last post? Can the driver/crossover/cabinet interaction theory explain the improvement I experienced across all recordings, regardless of their absolute polarity?

Still confused...

Rleff - No test equipment, unfortunately. I'm just a simple audiophile. :)

Glai - Interesting. Are you saying that you inverted the polarity of the woofer ONLY, and not the tweeter and midrange?

Glai - Your case is different, I believe, from what I posted in the OP. You changed the polarity of ONE driver, while I changed the polarity of BOTH drivers, which is why the perceived improvement in my case was such a mystery.

The improvement in your case, I'm guessing, is the result of a certain amount of cancellation between the midrange and the woofer when they are wired with opposite polarity, which in your room, has the fortunate effect of counteracting your room modes. Is that right?

If so, that's a different phenomenon than the one I experienced.