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08-26-2013
#1
help me understand this.....phase vs polarity
I had a discussion with a fellow member about phase, and polarity yesterday. We were discussing 180° phase shifts, and how it sounded different in my car than polarity swaps. He said they were identical, I didn't believe it because they sound totally different in my car. I explained that when installing my midbasses that I had to have the polarity right in order to get bass, when the polarity was opposite, I got cancellation, but after getting polarity correct, I could shift phase 180° and not get cancellation. It would just "detach" the sound from the drivers, and reduce localization. He insisted they were one and the same, and I had no arhuement to offer other than they sound different. After our discussion, I pictured a sine wave, and started to se where he was coming from.....holy shit that makes sense, but I still new the sound was different. That lead to a Google search, and this.........
http://totalproaudio.stevebunting.co...e-or-polarity/
Now this told me I was correct with my origional statement, and told me why they sounded different......but, I still don't have my head around explaining to someone the difference between the two. Now I probably should have gotten this from the link above, but its giving my head fits, I realize that they look the same in a sine wave, but the phase comes from delay.......but I can't put it together.......any of you guys care to break it down in layman's terms for me? Why no cancellation when it looks the same on an o-scope? I need some help with this!
Last edited by BigAl205; 08-29-2013 at 12:27 PM.
Reason: Clarified title
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08-26-2013
#2
Re: help me understand this.....
How did you shift the phase 180 degrees?
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08-26-2013
#3
Re: help me understand this.....
With the dsp in my head unit......
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08-27-2013
#4
Re: help me understand this.....
Methinks your headunit is inverting polarity also..... Not shifting phase.
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08-27-2013
#5
Woobooster
Re: help me understand this.....
Most dsp's flip polarity, even if phase is mentioned...
Is it correct to say?:
Polarity flips the entire signal ( frequency independent ) without time being a factor.
Phaseshift is a shift in time and is frequency dependent.( because every frequency has a different wavelength )
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08-27-2013
#6
Re: help me understand this.....
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08-27-2013
#7
Woobooster
Re: help me understand this.....
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08-27-2013
#8
Re: help me understand this.....
I was thinking about this stuff the other day, I had to stop because I shorted out my last remaining brain cell. Throw time alignment in the mix if you want some extra fun.
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08-27-2013
#9
Re: help me understand this.....
I was needing some input, I don't think my head unit is flipping polarity, because it sounds way different than a manual polarity swap......with a manaul polarity swap
I get major cancellation, when switching phase on my headunit....no cancellation. Anyways, I still couldn't explain the difference between 180° phase shift, and a polarity swap......other than the way they wind up looking the same on a sine......phase by delay, polarity by inversion.....
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08-27-2013
#10
Woobooster
Re: help me understand this.....
What do you want to achieve? Or just curiousity?
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