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RE: More about Absolute Polarity

Posted by harecording (P) on December 16, 2008 at 19:48:50

In Reply to: More about Absolute Polarity posted by HiOnFi on December 16, 2008 at 15:25:38:

There is an issue with this that you audiophiles do not address: Positive polarity. You guys are missing the point with absolute polarity. 99.9 percent of the speakers made today move out first, using negative polarity. That is opposite of how sound hits the microphone diaghragm. So, by flipping all channels to acheive "absolute polarity", you are getting closer to positive polarity, which would make for absolute polarity IMO.

JBL was the big proponent of positive polarity, and Altec Lansing was into it. If you go to JBL's website, you can find the white papers on this topic. JBLs drivers had their leads reveresed, compared to the rest of the world, to facilitate positive polarity. They did this until the late 80s. Then they gave in and switched to be like everyone else.

There is also a misconception that phase and polarity are the same. They are not. The two terms cannot be interchanged. You can have two signals with the same polarity, out of phase. You can have to signals, one with polarity inverted, in phase.

The fact that a Behringer or any other processor allows for polarity flipping does not mean that it facilitates or allows for absolute phase. In fact, the Behringer is utter crap, because it's processes cause latency. This latency is not compensated for. all you high end baffoons that think this box is stellar have no ears and/or poor acoustics, because any time you use these processes, the latency is adding delay, which is smearing your signal, because this box does not allow for perfect time alignment. It cannot. It is a dumb unit. There is no delay compensation.

The dbx driverack is the same way. Only the dsp on the INPUTS has delay compensation. And it is not perfect, It is course. There is no delay compensation for dsp on the outputs. So with these units, you really need SIA SMAART, TEF or some other time measurement software/device that allows you to set up your system, and then measure time arrival for each band, and then add delay to the ones with lesser processing so that everything is in phase from there to amp to speaker.

Of course, the room and physical placement will have some effect on phasing. So that is where an all pass filter will come in handy. You might need 225Hz rotated 65 degrees. This is what that is for.

Edits: 12/16/08

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