Subs w/magnet out, Reverse Polarity?

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stevdart

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Posted: August 09, 2004 at 9:02 PM / IP Logged

No, Alpine Guy, nobody is saying that reversing the wires makes no difference to the polarity. Of course it does. What makes a difference is the travel of the sound waves from the sub to our ears. Every environment is different, and just a change in placement of the enclosure will make a difference. How those sound waves react with the subs location and environment before they reach your ears in the driver's seat determines whether you want to switch polarity or not. The point is that, what DYohn so very well said, a speaker is moving in and out equally. So you can't damage them by reversing polarity.

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Alpine Guy

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Posted: August 09, 2004 at 9:35 PM / IP Logged

Excellent, , its all clear now! Learn sumthin new everyday

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94legend

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Posted: August 09, 2004 at 9:47 PM / IP Logged

stevdart wrote:

94Legend, I remember a post you put up about a three-sub system with one sub in reverse. Remember it? That is a case wher you have to be certain that the inverted sub is connected in reverse of the other normally mounted subs. Other than that, one can switch the wires to the amp all he wants, and one should actually always try it out, too, to see which phase sounds best from inside the car. I just recently switched my sub amp to 180 using the switch, and it seems the bass is a little better that way.

And DYohn, please feel free to digress all you want. When you talk, I (among others) am getting an education! :)

Hey thanks, This was very helpful, gave us the option to switch it around and experiment. Other wise we would have been 1 option less.

I would want to test it. but dont wanna flick with the customers car until i am certain of what i am doing. I'm gonna flick around with my subs,

Running two 12" DVC's i'm going to flip one around (inverted) and see how well the bass sounds. That way if i destroy my rear interior i wont get sued.

DYohn

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Posted: August 09, 2004 at 9:49 PM / IP Logged

Hey Alpine guy, you are comparing apples to oranges (to use an old cliche.) You are talking about two woofers interacting with each other. I am talking about the electrical and physical behavior of any speaker system by itself.

In your example #1, stevdart is correct, you see lots of movement and little sound due to the worst case condition, 180 degree polarity difference with one speaker moving the other one. (A very common beginner's mistake with dual-driver systems, by the way.) In example #2, the reason the SPL apparently decreased when you reversed both connections has nothing to do with the physics of the woofers (unless they are defective.) It was most likely an anomoly - unless there is a passive crossover (or Zobel network) in the system.

Take any single woofer. Connect it positive to positive on the amp. Enclosure doesn't matter. Measure the SPL output. Now reverse the polarity. Measure the SPL output. It will be the same, only the phase of the soundwaves will be inverted. Speaker polarity is marked for convenience. Polarity only matters when comparing one speaker to another, as you proved in your example #1.

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auex

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Posted: August 09, 2004 at 10:08 PM / IP Logged

Holy crap, all this for a simple answer. No polarity doesn't matter as long as both subs are moving the same direction at the same time. There are exceptions when tuning for SQ competitions but to most people will not really hear the difference, only an RTA can see the difference. Now if you have one sub mounted regular and one inverted then you must reverse the polarity at one of the speakers so that they move in the same direction at the same time. If the subs are mounted in the same manner, regular or inverted, then you only need the have them hooked up correctly.

Now I bet this will spark a hole different debate regarding phase alignment, where polarity will have an effect, and everything else.

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stevdart

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Posted: August 09, 2004 at 10:16 PM / IP Logged

No debate, auex, because you said nothing that wasn't already said.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

xtreamcc

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Posted: August 09, 2004 at 10:17 PM / IP Logged

Alpine, u should invest in a respirator Subs w/magnet out, Reverse Polarity? - Page 3 -- posted image.

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Alpine Guy

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Posted: August 09, 2004 at 10:50 PM / IP Logged

xtreamcc wrote:

Alpine, u should invest in a respirator Subs w/magnet out, Reverse Polarity? - Page 3 -- posted image.

lol, just bought 1 tonight, , i was a lil more accurate this time when i was applying the fiberglass haha, , not so messy.

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zane9000

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Posted: August 10, 2004 at 10:38 AM / IP Logged

im putting two 8" subs into a single chamber tube enclosure with one sub faceing out of each end. they chamber will have about 1cf of air (each sub calls for .5cf) and the length of the tube will be roughly 4ft. since they will be facing away from eachother i assume that i need to wire them out of phase, but i was just wondering what would happen if i didnt considering the distance between the two subs?

thanks,

warren

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stevdart

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Posted: August 10, 2004 at 10:45 AM / IP Logged

zane, they're sharing the same enclosure space, so you cannot wire them out of phase with each other. See the previous posts in this thread. It doesn't matter how long the tube is, it's still one air space.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

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