OEM speaker wires reversed

[Carrera4Boy'sDad]

We've just completed swapping the OEM dash speakers for Alpine SPG-10C2.

To do this the clever boy designed and 3D printed a mount (it required cutting off one of the Alpine 's tangs to fit properly) and I cut out the OEM speaker connector block so that we could plug it into the cars wiring.



Whilst doing it I noticed that the OEM speaker wires are reversed for the connector block. i,e on the left (passenger) side the black wire (positive), as expected, goes into the speaker connector block with a + printed on that side.
Bizarrely, on the right (drivers) side the black wire (again I believe +ve) goes into the opposite side of the connector block and it is the green/black wire which sits next to the + printed on the block. I assume the black wire is always positive.

You may be able to tell what I mean from this picture (not my speakers). Compare which side of the connector block the equivalent wires go to:




Strange how Porsche managed to make a buggers muddle of this simple wiring.

 

[Alex]

That's bad. Gonna bug me now that one of speakers polarity is reversed!!!!

 

[Carrera4Boy'sDad]

That's bad. Gonna bug me now that one of speakers polarity is reversed!!!!

Yes.
We did the rear speakers last year, so now I'm wondering if I got the polarity correct on those.

 

[911munKy]

IIt will work but reduce the bass. I’d swap the wires over, you could try both connections before you make a permanent fix to hear the difference in sound quality.

 

[gizlaroc]

Agree, it will cancel out the low frequencies of each other so should be pretty obvious which one sounds fuller. Might need to turn the bass up a few clicks and fade it to the front to make it more obvious.

 

[Carrera4Boy'sDad]

It surely must mean that ever since the car's manufacture, one Nokia bass speaker cancelled out the other ??

 

[GMG]

...I like my HiFi Naim now but previously separates and always understood that reverse polarity impacts the Bass ? Like Alex this would do my nut in!

 

[maldren]

The polarity of the speaker determines whether the cone is moving forwards or back as a signal is applied. I have certainly known speakers from well known manufacturers where they are built and then tested for polarity and marked with a '+'. The colour of the wires doesn't always show +ve and -ve.

If you have them out of phase and they are close to each other, the signals cancel each other out and give a strange effect. When spaced apart, the stereo effect is confused. Easy to test by feeding a signal into them, listen and then change the +/- on one speaker.

 

[Carrera4Boy'sDad]

I'm starting to doubt now that the black wire is always positive.
Looking at this photo, it seems the black is +ve on one side, yet -ve on the other. But why did Porsche deliberately do this I wonder ?

 

[Ozone]

My car was built with the factory non-Bose amp. The previous owner had the speakers changed, different head unit and the amp bypassed
I noticed the audio was very odd. One day I put my head down to the door speaker, it sounded great, but when I lifted my head up it sounded odd again. I swapped the polarity of the rear speakers, now it sounded great when sat normally in the car.
I later checked the wiring diagram in the Bentley manual, the rear speakers are reversed at the factory. Care point for anyone bypassing the amp!

 

[GrafZero]

Some time ago I was reversing the audio modifications some clever Japanese made to the car and I made the same mistake on one of the door speakers, but it was immediately noticeable as the sound was changing dramatically when I moved my head around the interior.

PS: If you don't have the right tool, you should still be able to check the polarity with a low power LED

 

[YPVS]

IIt will work but reduce the bass. I’d swap the wires over, you could try both connections before you make a permanent fix to hear the difference in sound quality.

You know what, the base is poor on the speaker upgrade I did. I'm wondering if I checked this now.