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
IIUC you reversed the spkr cable connections, right?
If the sound is really better, it is probably your room acoustics favouring 180 degrees change in phase.

Do you have the impression of a deeper soundstage now?
phase inversion is a strange phenomenon.
My preamp has an invert function which I some times experiment with if the music sounds lame. Sometimes a substantial improvement, sometimes barely any difference, sometimes a degradation occurs. Sometimes even different cuts on the same record / CD prefer different phase.

Sorry Byron I can't explain this although I can certainly validate your findings. Trouble with hardwired phase inversion is it's not adaptable. I guess go with whatever sounds best the majority of the time. Interesting post --- thanks.
There was a very interesting article published years ago about absolute/relative phase. "The Wood Effect" by Clark Johnson.
I believe that all you did was change the sound for those disks recorded in one polarity (e.g., inverted, non-inverted). So while those disks may sound better, the ones recorded in the opposite polarity should sound worse. However, since the speaker drivers are apparently not polarity-coherent to begin with, I'm surprised you could hear any difference.
One sure way to check the drivers, crossover, and internal wiring of the speaker is to place a
1 - 1/2 volt D cell battery across the external speaker box terminals. Disconnect the speaker cables from the speaker box terminals. Connect two test lead wires to the speaker box terminals long enough so you can view the drivers from the front. Tag the test lead that is connected to the positive speaker terminal. Use your fingers to hold the neg test wire on the neg post of the battery. Momentary touch the positive test wire to the positive post of the battery. The woofer cone should push forward, not suck back.
Not sure if you will see any movement in the other speaker driver.
The fact that you think it sounds better doesn't mean it is performing better. It could be a problem with how the speaker mates with your room. Here are the Stereophile measurements.
Hi Bryon,

Gee, that's a tough one, assuming as you indicate that the effect is repeatable across a wide range of recordings, presumably ruling out the polarity of the recording as being a factor.

The one possibility that occurs to me is that the output of your power amp has some amount of dc offset present, due either to itself or to the preamp or processor that is feeding it, or the source component for that matter (if the entire signal path is dc coupled). Does your friend, who observed the same phenomenon, have similar electronics?

A dc offset would cause your woofers to have a rest position that is either slightly forward or slightly backward relative to their normal zero-signal rest position, the direction depending on the polarity of the offset (and therefore depending on the polarity with which the speakers are connected to the amplifier).

That would tend to bias the contribution of the woofers such that acoustic compressions or rarefactions in the speakers' outputs are slightly emphasized or deemphasized relative to one another, depending on the polarity of your connections but independent of the polarity of the recording. I think :)

That's just a wild guess, of course, but it's the only theory I can think of that seems to fit all the facts.

Best regards,
-- Al
Jea48...Some driver manufacturers (JBL for example) use the oposite polarity definition (cone pulls in).
Some driver manufacturers (JBL for example) use the oposite polarity definition (cone pulls in).
Eldartford,

True..... My point was to verify the polarity was indeed reversed on the driver/s and with the test make sure both speaker box units are in phase with one another. http://recforums.prosoundweb.com/index.php/mv/msg/2661/29039/0#msg_29039
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?
How would I know if my system had a DC offset?
Hi Bryon,

You would need a good multimeter, preferably a digital one that can measure dc voltage with a resolution adequate to read say a few millivolts (mv), or ten's of mv at most.

You would power up the entire system, let it warm up for a few minutes, and set the multimeter to measure dc voltage. With no music playing you would then place the two leads of the multimeter between the red and black speaker terminals of one channel, or between the corresponding terminals on the amplifier. Repeat for the other channel.

I don't particularly have a feel for what the upper limit of acceptability would be for the reading. Perhaps someone else reading this will. But I would feel fairly comfortable with a reading of say 60db below the voltage that, were it ac, would result in the 88db spl that your speakers are rated to produce, at 1 meter, in response to an ac input of 2.83 volts. 60db below 2.83 volts is 2.83 millivolts.

Hope that helps,
-- Al
Al - I believe I have a digital multimeter around here somewhere. I will look for it and report back my findings. Thanks!
expect a typical offset under 30mv = 0.030 volts DC

This is obviously a longshot. Two completely different setups with the same exact 'issue' is highly unlikely.
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.
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
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.
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.
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
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.
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.
Bryoncunningham 2-18-10

so that the speakers are still in phase with each other,
Am I wrong, aren't the two speakers still out of phase with one another.

If the woofer, bass driver, is now wired so when a kick pedal strikes the bass drum does the speaker produce the same amount of energy, air movement, sucking back as it did wired the other way pushing out? Does the woofer now produce less bass?
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.
Hi Bryon,

I agree completely with everything in your preceding post.
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.
While the polarity inversion of the tweeter relative to the woofer is certainly relevant to the sound of the system (and I believe, although I'm not totally certain, that the inversion is necessary to flatten the frequency response of the speaker given the particular crossover design), the bottom line is simply that two inversions in the signal path (prior to the speaker) and/or in the recording = no inversions, regardless of how the tweeter and woofer are phased relative to each other.

Let's say that the speaker connections are reversed, and that a polarity-correct recording is being played, and that imaging is improved for that recording relative to what it was with the speaker connections not reversed. In that situation the tweeter's output will be polarity correct relative to the original event, and the woofer's output will be inverted relative to the original event.

If we now play a recording that has inverted polarity, with the speaker connections still reversed, the tweeter's output will be inverted relative to the original event, while the woofer's output will be polarity correct relative to the original event. Which is the same situation that we had with the previous recording when the speaker connections were not reversed, which resulted in inferior sound on that recording.

So the fact that reversing speaker connections provides improvement that is consistent regardless of the polarity of the recording is what is so baffling.

Another way to look at it is to consider Figure 7 of John Atkinson's measurements, linked to in earlier posts. That depicts the speaker's response to a positive-going pulse or step waveform, which by definition (or, more precisely, by Fourier theory) includes sinusoidal spectral components at both low frequencies and high frequencies. The initial response to the application of that waveform is a negative-going half-sine wave, since the (inverting) tweeter responds to the signal's high frequency content sooner than the woofer can begin to respond to lower frequencies (and also because the path length from listener to tweeter is slightly less than the path length from listener to woofer, as you noted). The response to that high frequency spectral component eventually oscillates to a positive-going half cycle, at which time the output of the woofer starts to predominate, beginning with a low frequency positive-going half-sine wave, and eventually oscillating to be negative-going.

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. If the polarity of the recording were then inverted, that ENTIRE waveform would then be re-inverted back to what it was for a non-inverted recording with non-inverted speaker connections.

I hope that further clarifies my befuddlement :)

Best regards,
-- Al
Bryoncunningham,

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. Am I still wrong.

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

No doubt you and Al are a hell of a lot smarter on this subject than I am.
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.

But assuming that the sonic effects reverse as predicted . . . I didn't read that you reversed the speaker cables themselves at the same time? While I don't think that the absolute phase of small loudspeakers such as yours will make much difference per se, keep in mind that if you invert absolute phase at the speaker, you're changing the left/right speakers' relative phase in relation to the subwoofer, which I would expect to be audible. So it's important to establish the effects of simply reversing the phase of (both) your main speakers, independently of reversing the phase of the individual driver connections.

Okay, so assuming that you're noticing a difference in the sound when you reverse the individual driver leads, but also reverse the speaker cables themselves (to preserve absolute phase) . . . then the most likely explanation is that the loudspeakers' drivers/cabinet and crossover interact with each other differently when the phase is inverted . . .

. . . and a couple of things come to mind here. First, this speaker uses a 36dB/octave 2-way network? That means a minimum of six capacitors and six inductors, and that's quite a bit to fit into that small cabinet . . . so some of the inductors are probably metal-core, and maybe one or two of the caps is an electrolytic? So it's possible that the bass portion of the crossover has a significant nonlinear transfer function, and the woofer/cabinet together definately have a nonlinear transfer function. So when you invert the phase between the drivers and crossover, you will be altering how these two transfer functions combine with each other, which may have some subtle effects on the transition-band behavior.

But finally (moving on to my favorite theoretical speculation), even assuming the crossovers' components themseves are pretty much ideal, all the inductors are going to be in fairly physically close each other, and to the woofer motor structure as well. I can also confirm from experience that subtle changes in the orientation and layout of crossover inductors can measurably affect the response of the crossover, and the woofer motor can produce a significant alternating magnetic field as a result of its modulation. 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.
I was saying the two drivers housed inside each box speaker are wired out of phase with respect to one another.
Yes, that's correct, Jim. That is done intentionally in some speaker designs, and as I said in my previous post I believe it is necessary in those cases to achieve 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?
Excellent question. Obviously inverting the connection polarity to the main speakers changes the phasing of mains vs. sub by 180 degrees. Presumably that would only affect frequencies for which the sub produces significant output, which presumably don't play a major role in imaging, but considering that we can't come up with any other explanations that hold water the experiment you suggest seems well worth trying.

Best regards,
-- Al
Both the woofer and tweeter are connected through a crossover which causes phase shift as a function of frequency (and order of the crossover). At the crossover frequency both drivers are equally loud. You want them to be in phase at this frequency or else they will counteract each other. If the phase difference is 180 degrees you will need to connect the two drivers with oposite polarity. If the phase difference is something other than 180 degrees neither wiring polarity is perfect. Try it both ways and pick what sounds or measures best.

Relative position of the two drivers also affects the acoustic phase. It is easy to tell when driver polarity is wrong: there will be a deep notch at the crossover frequency
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?
Fascinating. But would this effect be constant across all recordings with different absolute polarities?
Yes, this has nothing to do with absolute phase . . . it's more of a component-layout issue.

Here's an example - if you were to take two identical raw crossover inductors, and wire them in series . . . the electrical result is theoretically double the value of a single one, that is, the values add. However, if you stack them one on top of each other like doughnuts, the two magnetic fields around them will interact, and the overall inductance will either increase or decrease, depending on which way they're stacked. Because stacked one way, the fields will be going with each other and combine, but if you flip one of them over the fields will be working against each other thus cancel each other out a little bit.

But of course instead of physically flipping one of them over, you could simply reverse it's leads and get the same result. Now in your case, my speculation is that the interaction is between the woofer and one or more of its associated low-pass series inductors. Here, reversing the relative phase between the crossover and the woofer could somewhat change some of the inductors' effective values, and this would happen even if the polarity was also inverted on the speaker input to preserve absolute phase.

One of the downsides of using a steep sixth-order crossover design is that the required tolerances for the component values is much more critical to acheive the desired crossover slope. And changing the crossover slope affects not simply the summed frequency response, but also the speaker's directivity charactericts through the transition band - and this is something I would very much associate with a perceived change in imaging.
Hi Kirk,

Thanks for your characteristically knowledgeable response.

However, I think you may have misread or misinterpreted some of the earlier posts. As I understand it, Bryon has done nothing internally within the speakers. All he has done is to interchange red and black at the external terminals of each speaker, and also the sub, thereby inverting absolute phase. The result was improved imaging, which mystifyingly seems to occur consistently on a very wide selection of recordings, presumably encompassing some recordings that are absolute phase correct, some recordings that are inverted, and some recordings that are a random mix of phasings for the different instruments and/or voices that are present.

Given that, I'm not sure that the theory you have offered is applicable.

Best regards,
-- Al
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...
Got any test equipment like a o scope;if so I would put channel one on the input of speaker and then input a ac sine wave signal and look at the other drivers vs the input signal to see if the signal at the driver itself tracks with the input or is inverted;also I would use different frequencies and amplitudes.
Rleff - No test equipment, unfortunately. I'm just a simple audiophile. :)
Have you used any test cd's with phase test signals to try and help you understand this situation?
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.
From this statement, 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?
Kirkus, that was also my initial assumption --

Anyway, a 180d change can produce a relative suckout in the lower-mid area, whereby the perceived result is more clarity ion the upper register (=better imaging) and a more pronounced upper bass region.
Kirkus,

That is the way I read the OP at first as well. But through later responses from Bryoncunningham I believe he just reversed the speaker cable leads at each of the box speaker terminals.


Anyway, a 180d change can produce a relative suckout in the lower-mid area, whereby the perceived result is more clarity ion the upper register (=better imaging) and a more pronounced upper bass region.
02-24-10: Gregm

Gregm,

What if instead of reversing the polarity at the box speaker terminals Bryoncunningham pulled the midrange/hi-frequency driver and reversed the polarity there? Then reconnect the speaker cables from the amp to the speakers + to +, - to -.
Changing the relative phase between the woofer and tweeter will of course alter the summed power response, as well as the vertical dispersion charasteristics, of the complete speaker.

But I think it's clear that the relative phase between the two drivers has been preserved the whole time . . . what's still unclear to me is whether the relative phase between the drivers and the passive crossover has been changed, or simply the relative phase between the loudspeaker and amplifier. And I'm also not sure under which conditions absolute phase has been preserved or altered . . . so it's difficult to make further speculation.
You can simulate this situation using a simulation program although you would need to know the layout of the crossover with component values and connections;LT Spice a free simulation program could do this if you wanted to take the time to download it and then input the needed data(crossover circuit and drivers) then run the simulation and look at the outputs of voltage vs current using the tools in the simulation program.You would see phase relationships as they occur at runtine at any node(test point) in the crossover to the driver(s).
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?
Kirkus - In light of this information, does your initial crossover/driver/cabinet theory still apply?
No, sorry, it doesn't. There are only three things that I can think of can explain what you're experiencing:

- Psychological or experimental change, like improving the speaker connections in the process.

- 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

- The amplifier somehow performs slightly differently when its connection to the speaker is reversed. Speculation about this in further detail would require some pretty obscure types of data to be measured pertaining to the loudspeaker, the amplifier, and the speaker cable . . .
- 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.
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!
The thread strikes me as having been a very worthwhile intellectual exercise, with the thoughts that have been presented having potential applicability to other situations in the future. Not a waste of time at all.

Best regards,
-- Al
I agree with Al.
Along the same lines, I have Verity Sarastros which have first order crossovers, all drivers in same polarity with rear facing woofer. As a result, there is large overlap of the midrange and woofer. My room has some inherent narrow band peaks at 50Hz and 80Hz. When I invert the polarity of the woofer, these peaks completely went away and I was left with a near ideal frequency response with no peaks. Base is cleaner, tighter. The soundstage is deeper but some instruments are more difficult to localize in the soundfield. I am bit surprised because violins does not have much energy below 100Hz.

I understand that there is more to just a flat frequency response. What is the ramification of this?
Glai - Interesting. Are you saying that you inverted the polarity of the woofer ONLY, and not the tweeter and midrange?
Yes, that is correct.
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.