How to determine speaker wire polarity?

[Lolvoguy]

On the BMW in my sig, during the late 90's the PO had a "professional" shop re-run wires from the head to the 4 speaker locations in the car so he could have a Sony deck installed.
So now the stereo wiring to the speakers looks all the same color etc.

I've noticed that the two rear channels (or maybe it's the RF and RR) are mixed up when doing balance and fade.
I'm currently installing a new Continental car stereo and I'd like to confirm all 4 speaker locations' polarity.
Without having another person in the car (and a spare 9v battery) is there a way using a multi meter I can test and label them correctly before I connect them to my new radio?

thanks in advance

 

[Traction]

Just ground 1 wire at a time, and check the other end to ground with your ohmmeter.

 

[Lolvoguy]

what does that determine?
what settings to put meter on?

thanks for the reply

 

[RooflessVW]

Take a AAA and two test leads. Tap the leads to the + and - poles of the battery. If the speaker pops out, you've got it correct. If it pops in, the polarity is reversed.

 

[DuckRyder]

The fade and balance are the speaker leads being incorrectly connected by channel at the deck.

It would help to know if you are working with factory speakers or aftermarket generally aftermarket speakers the negative terminal is a smaller blade.
i don't recall what factory E30 speakers look like for the connection.

I assume you have looked around for the factory wires, it would be surprising if they actually removed the entire OE harness. I also assume that you've examined the replacement wire for + and - written on the wires and for striped wires? Some aftermarket speaker wire of the era also had square insulation on one wire and round on the other.

If they are indeed all the same then the idea of disconnecting both ends and testing with an ohm meter is a good one.

 

[barryh]

Getting speaker wire polarity wrong will impact on bass response as with the speakers out of phase you get a cancellation effect.

 

[jetmech1]

Originally Posted by rooflessVW
Take a AAA and two test leads. Tap the leads to the + and - poles of the battery. If the speaker pops out, you've got it correct. If it pops in, the polarity is reversed.


That will tell you the polarity of the speaker itself. Believe the OP is needing to determine polarity of unmarked speaker leads.

From your description, it sounds like they used speaker leads with same outer jacket color (or did they use clear)? Either way, IF they did use speaker wire, does each lead have 1 copper appearing conductor and the other silver? Generally, the copper side is used for + polarity. If both conductors are same color, then look closely at the outer insulation jacket. Normally, one side has ribs or a line running along the outside and the other side is smooth. Ribbed side is +positive.

To isolate/find each speaker location, do it this way: Disconnect all speaker locations. Then one at a time twist 1 speaker lead together. Go to the head unit and set your multimeter on beep continunity and one at a time find the speaker lead that has continunity. If your multimeter doesn't have beep setting, use RX1. Only the speaker lead that's twisted should have continunity. Mark each lead using this method. BTW, if you can't determing which conductor to mark as + pos. get a length of any good flexible wire (any gauge will work 20,18,16 etc) long enough to reach from the head unit to each speaker location. Connect it to 1 side only of each speaker lead and then connect your multimeter to that "test lead" and find which of the 2 speaker lead conductors shows continunity. Make that your + pos. lead. Finally, assuming your new stereo has a CD player, this inexpensive tester works like a champ at testing correct phasing once everything is hooked and playing here is a link. Speaker phase tester Amazon

GOOD LUCK!!!

 

[edwardh1]

this

 

[StevieC]

You can also use a 9 volt battery on the speakers wire connectors. Won't hurt anything but you will be able to tell that way.

 

[skyactiv]

Originally Posted by StevieC
You can also use a 9 volt battery on the speakers wire connectors. Won't hurt anything but you will be able to tell that way.


I remember my brother doing that. That speaker pushed out towards the speaker grill when connected correctly.

 

[EdwardC]

Any change you or someone you know has an oscilloscope? That would make it pretty easy to see.

So, I've never done this, but it seems like it should work:

Play a single frequency test tone (can use a frequency generator app from a phone) and set the balance and fader to their midpoints. Take one of the speakers and measure the AC voltage between the + and -. Lets hypothetically say that you measure 5VAC. Next take the next speaker and measure the voltage between the two "positive" wires of the two speakers. If the voltage measured is low (or ideally zero), they're in phase. If you measure a voltage closer to the individual speaker output, (our hypothetical 5VAC), they're out of phase.


Edit: Nevermind, you aren't looking for the polarity of the HU's output, just the speakers.

 

[Lolvoguy]

Thanks for the help guys. Got it all figured out with your suggestions.
This Bluetooth tech is faaaannncy! Makes listening to my fave tunes so much better than before!
No more need to burn CD's! And I can actually talk hands free on my phone using a radio that looks like it's from the 80's!

 

[JHZR2]

Originally Posted by rooflessVW
Take a AAA and two test leads. Tap the leads to the + and - poles of the battery. If the speaker pops out, you've got it correct. If it pops in, the polarity is reversed.


That's how I learned to do it...

 

[jetmech1]

Originally Posted by jetmech1
Originally Posted by rooflessVW
Take a AAA and two test leads. Tap the leads to the + and - poles of the battery. If the speaker pops out, you've got it correct. If it pops in, the polarity is reversed.


That will tell you the polarity of the speaker itself. Believe the OP is needing to determine polarity of unmarked speaker leads.

From your description, it sounds like they used speaker leads with same outer jacket color (or did they use clear)? Either way, IF they did use speaker wire, does each lead have 1 copper appearing conductor and the other silver? Generally, the copper side is used for + polarity. If both conductors are same color, then look closely at the outer insulation jacket. Normally, one side has ribs or a line running along the outside and the other side is smooth. Ribbed side is +positive.

To isolate/find each speaker location, do it this way: Disconnect all speaker locations. Then one at a time twist 1 speaker lead together. Go to the head unit and set your multimeter on beep continunity and one at a time find the speaker lead that has continunity. If your multimeter doesn't have beep setting, use RX1. Only the speaker lead that's twisted should have continunity. Mark each lead using this method. BTW, if you can't determing which conductor to mark as + pos. get a length of any good flexible wire (any gauge will work 20,18,16 etc) long enough to reach from the head unit to each speaker location. Connect it to 1 side only of each speaker lead and then connect your multimeter to that "test lead" and find which of the 2 speaker lead conductors shows continunity. Make that your + pos. lead. Finally, assuming your new stereo has a CD player, this inexpensive tester works like a champ at testing correct phasing once everything is hooked and playing here is a link. Speaker phase tester Amazon

GOOD LUCK!!!


Well, I went back and re-read your post and realized that you probably don't have the speaker ends exposed. The 9 volt battery does work great IF you can see which way the speaker cone is moving. You can also make the speaker produce an audible pop by "dancing" the wire across the battery terminal. Can determing each location that way.
Trouble is, you indicate you're working solo. You're going to have to have loooong pigtails from the battery so you can watch each speaker move. However, having installed "systems" for decades, I would highly recommend upgrading the speakers if they're 90's vintage. Auto speakers take a beating and their sound reproduction really degrades with age. Most likely those cones are ready to go if they already haven't. Being garaged does extend this some, but if they're the OEM or even been replaced in the 90's, I'd really consider upgrading them so you have a fresh system.

 

[Mainia]

Call Crutcfeild, they will be more then happy to give you the color codes. Then remember where you got help next time you buy stereo stuff.

 

[Lolvoguy]

Originally Posted by Mainia
Call Crutcfeild, they will be more then happy to give you the color codes. Then remember where you got help next time you buy stereo stuff.

from above:

"during the late 90's the PO had a "professional" shop re-run wires from the head to the 4 speaker locations in the car so he could have a Sony deck installed.
So now the stereo wiring to the speakers looks all the same color etc."

but thanks for participating