Polarity mystery: Can you help me solve it?

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 . . .

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.

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.

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?

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.