Metra Speaker Harness Polarity

Jebiruph

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The mid-range of my system with newly installed Infinity 3.5" speakers was terrible. Having a vague memory of a mention that the polarity of Metra speaker harnesses was reversed, I checked and verified that this was the case, at least for the Metra 72-7902 when plugged in to a JL/JT.

Here's the left front speaker wiring schematic. Grey/violet is (+), grey/yellow is (-).
LF speaker wires.PNG

The white wire of the Metra harness has the large spade connector and connects to the (+) of the speaker, but it connects to the grey/yellow (-) speaker wire. Here's a picture of the harness plugged in. Mine's been modified, but you can see in the pic that the grey/yellow wire connects to the white Metra wire that would have connected to the speaker positive if I hadn't reversed it.
metra speaker harness.jpg


Reversing the polarity of the 3.5" speakers and not the 4" speakers means that the 3.5" are pushing out when the 4" are pulling in and this causes distortion of both the sound wave and the stereo effect. This "out of phaseness" was tolerable enough in my JL that I didn't notice it much and ran that way for over a year. But this same system sounded terrible in my JT, so I decided to check the wiring. Now with both systems corrected they sound great, even if somewhat bass less.





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cm88_bruins

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My crutchfield order came with Metra 72-6514. Now I want to go check...
 

StingGrayJLU

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This makes a lot of sense. I just added an amp and replaced my front speakers and am not too pleased with the results.

Sucks because it’ll be a pain to get to the lower dash speakers again, but worth a shot. I guess I could just swap the + and - wires at the amp
 
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This makes a lot of sense. I just added an amp and replaced my front speakers and am not too pleased with the results.

Sucks because it’ll be a pain to get to the lower dash speakers again, but worth a shot. I guess I could just swap the + and - wires at the amp
If you reverse the polarity of all the speakers, your speakers will not be out of phase with each other.
 

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Hey man I checked mine today. I decided to just use a 9V battery to see which way the speaker would go and man mine were reversed polarity too. I spent all day fixing it. But man was it worth it. It doesn’t sound like I’m in a tunnel anymore. Big difference. Thanks man.
 
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Hey man I checked mine today. I decided to just use a 9V battery to see which way the speaker would go and man mine were reversed polarity too. I spent all day fixing it. But man was it worth it. It doesn’t sound like I’m in a tunnel anymore. Big difference. Thanks man.
Before I fixed mine, I thought my JL sounded pretty good, but at high volume the mid range fell apart. My JT was bad at almost any volume. Fixing the harnesses made all the difference.
 
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I was working on my sound bar speakers and took some pictures of the Metra harnesses plugged in, reversing the black and white wires.

72-6514
metra speaker harness 2.jpg


72-7902
metra speaker harness 3.jpg
 

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I called Crutchfield today to let them know. The Tech said they'd also notify Metra.
 
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You can use a small screw driver to release the wires from the plug and reinsert them in the correct location. You also have to open wire retainer on the 72-7902 to get the wires out.

Here's the wire retainer opened.
metra 72-7902 2.jpg


Here's looking into the connector at the release tabs above the wires.
metra 72-7902 1.jpg


Using a small screw driver to pry up on the tab to release the wire.
metra 72-7902 5.jpg


Looking into the empty connector for a better look at the release tabs.
metra 72-7902 3.jpg
 

emgeesea

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The mid-range of my system with newly installed Infinity 3.5" speakers was terrible. Having a vague memory of a mention that the polarity of Metra speaker harnesses was reversed, I checked and verified that this was the case, at least for the Metra 72-7902 when plugged in to a JL/JT.

Here's the left front speaker wiring schematic. Grey/violet is (+), grey/yellow is (-).
LF speaker wires.PNG

The white wire of the Metra harness has the large spade connector and connects to the (+) of the speaker, but it connects to the grey/yellow (-) speaker wire. Here's a picture of the harness plugged in. Mine's been modified, but you can see in the pic that the grey/yellow wire connects to the white Metra wire that would have connected to the speaker positive if I hadn't reversed it.
metra speaker harness.jpg


Reversing the polarity of the 3.5" speakers and not the 4" speakers means that the 3.5" are pushing out when the 4" are pulling in and this causes distortion of both the sound wave and the stereo effect. This "out of phaseness" was tolerable enough in my JL that I didn't notice it much and ran that way for over a year. But this same system sounded terrible in my JT, so I decided to check the wiring. Now with both systems corrected they sound great, even if somewhat bass less.
Do you know where to find this schematic for the roll bar speakers?
 

emgeesea

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Jebiruph

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Thanks. What's odd about those diagrams is the actual wire colors for the roll bar speakers in my 2020 JL are white and grey. So, I don't know how that aligns with the color codes on the schematic. Frustrating.
It only shows one right and one left speaker on the schematic. It looks like there is a white and grey wired splitter installed to connect the additional speakers.
 

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It only shows one right and one left speaker on the schematic. It looks like there is a white and grey wired splitter installed to connect the additional speakers.
Thanks. Trial and error revealed that in my JL the white factory wires in the roll bar are positive and the grey are negative.
 

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Hoping that I can tag onto this. I am planning to replace all of the speakers in all the locations in my JT Gladiator, which are identical to a 4 dr JL Wrangler.

Are people saying that _both_ the 72-7902 and the 72-6514 flip the polarity? If so the speakers should all stay in phase, and it's usually not a big deal if the phase of all of the speakers together are flipped as long as they are _all_ flipped, together.

Thanks!
 

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