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Switching polarity of tweeter in two-way design

In order to align the time&phase of the tweeter to the woofer in a two-way design, is it a common practice to switch the polarity of the tweeter so that it is slightly delay in time? It would be similar to having the baffle slanted at a small angle.

I think it is done on the ProAc 2.5 and probably on some of the DIY two way speakers
andy2
gs5556
1,250 posts
 
Not really. That will only work if the crossover frequency's wavelength is exactly twice the distance between the tweeter and midwoofer. And it would only work at that one frequency.
jeffreybehr's avatar
jeffreybehr
805 posts
 
The tweeter is wired 'backwards' not to time-align anything but to 'offset' the response spike that occurs in most 2-ways if the tweeter is not reverse-wired. I don't pretend to understand it, but the result is to NONtime-align the system.
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rockvirgo
587 posts
 
Agree with Jbehr. I always figured the reason for putting the tweeter out of phase was to cancel its response overlap with the woofer. Time aligned designs usually have some slant or tilt thing happening to place the tweeter farther away than the woofer.
eldartford
4,262 posts
 
I have seen frequency response plots of two way speaker systems with the tweeter hooked up each way. One shows a dramatic downward spike at crossover. Almost complete cancellation. In fact, this is the best way to determine the exact crossover frequency.

However, this effect is probably seen because the microphone is located at a small fixed spot in space, so that the distance to the two drivers is fixed. For real-world listening, polarity of the tweeter does not seem to make a lot of difference. Best idea is to try it both ways.
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