Hi Stereoquest.
Thanks for providing the insight about how crossovers work. I did some research around what you wrote and while I did not follow all of what they were saying they do seem to indicate that what you write is correct for some speakers - I think - it is not always clear what they are getting at.
For the Wilson Maxx 3 example we were using, reading the stereophile review does not seem to match up with what you are saying. Though I might be misunderstanding them. They show a step response (which is measured with a microphone at some point in front of the speaker), and they explain that the step response shows a positive initial response from the tweeter, and negative initial response from the midrange, and a positive initial response from the woofer. So whatever is happening with the crossover or the wiring of the midrange driver, the end result (for the listener/microphone) is that the microphone is picking up that the sound from the midrange is in inverted phase to the other drivers. Or is it. I am not sure - read on.
There is another stereophile article that on page three of the article expands on how step response is measured and shows measurements for different speaker system examples: http://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3
To me the second speaker they use as an example has similarities to the way the Maxx 3 is set up, and they show measurements in a similar way with the midrange having an initial negative response, yet at the end they have this conclusion which seems to agree with what you said:
"It appears that the designer of the speaker featured in these four graphs has chosen to use high-order crossover filters of some kind, which necessarily introduce significant (180 degrees or greater) phase shift in the crossover region. To this must be added the phase shift due to the time delay between the units, and the additional 180 degrees phase shift due to the inversion of the midrange's electrical polarity."
I read that as the midrange being about 360 degrees (maybe a little more) different to the other drivers, so basically in phase with the other drivers as you indicated. That seems to conflict with the measurements taken by the microphone. I would think the microphone should show the initial response of each driver to be positive yet it doesn't, the initial response of the midrange driver is negative. So I really don't know - consider me confused.
Back to the ET3 reviewer - um there has been some extra comments on the review.
Anthony
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