JBL Subwoofer (+ or Negative)

[awhughes]

On my 97 exp, which connection is positive or neagtive on the JBL subwoofer?

One connection is larger than the other.

 

[oplitic]

I've never had the stock sub, but I would think that the bigger wire would be positive. I would check with a multimeter though. Why do you want to figure out the wires? If you're thinking of putting a new amp, I wouldn't use them. I'd run new wires.

 

[awhughes]

I want to know which is positive because I am installing a new woofer. The new woofer has + and - marked on it, but I dont know what the wires are. The wires are not marked.

 

[oplitic]

I want to know which is positive because I am installing a new woofer. The new woofer has + and - marked on it, but I dont know what the wires are. The wires are not marked.

Oh, for the woofer itself, not the amp, sorry got it confused. Because you don't have two woofers, it won't matter how you hook it up. It will just technically be out of phase, but since you don't have a second woofer to hook up, you can't cancel out the sound it's going to produce.

 

[sstewart777]

It might make a difference if the woofer has a crossover/filter built into it. The high frequency filters won't work right if the polarity is reversed and the sound quality will suffer. You may have to try it both ways to see if there is any difference. If there is no crossover/filter built in then the woofer will work equally well both ways. You can use a set of alligator clips to try it out without having to change the ends around.

Good luck!

 

[oplitic]

It might make a difference if the woofer has a crossover/filter built into it. The high frequency filters won't work right if the polarity is reversed and the sound quality will suffer. You may have to try it both ways to see if there is any difference. If there is no crossover/filter built in then the woofer will work equally well both ways. You can use a set of alligator clips to try it out without having to change the ends around.

Good luck!

We're dealing with a sub so high frequencies are not involved. And even if it did have a filter or crossover, it's still sending out the same signal, just technically backwards to the speaker, which is fine cause it will play the same both ways, the only time you have to make sure it is the same polarity, is sub to sub (have the same wire going to neg and the other going to both pos), and you can even have both of those hooked up backwards, it's all the same.

 

[tc11362]

how to check?

How can you check polarity with a multimeter?

 

[sstewart777]

Hi,

You can't check polarity with a multi meter on the signal. You would have to look at it with an O-scope. What you could do is follow the wire back to the source and see if you can identify the polarity there.

Also, Oplitic is correct about the signal not having high feqs to deal with, if the signal is wired out specifically from a system that has a sub output. The crossover would be internal to the source at that point.

However, if the signal is coming from a stock system and you are trying to break out the low freqs there will be a crossover somewhere in line. There has to be.

Another thing to be careful of with a stock system is that sometimes they use a common return. That makes things kind of of interesting when adding equipment.

I do presume that if you are adding a sub, that you are not using a simple stock or cheap source.

 

[oplitic]

How can you check polarity with a multimeter?

When I originally said it I was thinking he was talking about the actual power and ground for the amp. As for which wire is pos and which is neg off the amp with a multimeter, I can't remember, I could tell ya tomorrow night sometime. I learned it in school but can't remember cause I never had to do it. I'll look in my books I have at home tomorrow. If I remember, lol.

I think you ground the multimeter, and check each wire (while the amp would be playing music) for which has AC voltage, cause speakers are AC not DC. I'm about 99% sure that's how. But let me double check.

 

[oplitic]

Hi,

You can't check polarity with a multi meter on the signal. You would have to look at it with an O-scope. What you could do is follow the wire back to the source and see if you can identify the polarity there.

Also, Oplitic is correct about the signal not having high feqs to deal with, if the signal is wired out specifically from a system that has a sub output. The crossover would be internal to the source at that point.

However, if the signal is coming from a stock system and you are trying to break out the low freqs there will be a crossover somewhere in line. There has to be.

Another thing to be careful of with a stock system is that sometimes they use a common return. That makes things kind of of interesting when adding equipment.

I do presume that if you are adding a sub, that you are not using a simple stock or cheap source.

As far as I can tell he's using a stock system, so it would be coming from the deck, I believe. I'm going by assumption that Ford did that from factory. I've never had teh stock sub in my Mounty, didn't come with one.

 

[awhughes]

Yes, Everything is stock. I am not adding anything to the system, just replacing a tired woofer. If the polarity is not an issue, why would the connectors coming from the amp (or wherever its coming from) to the woofer be different in size? The connector on one wire is almost twice the size of the other wire connector.

I will switch the wires today and remount to determine if my aging ears can tell any difference.

BTW, the original woofer was in bad shape when I removed it. The foam that connects the circumfrance of the paper to the metal frame of the speaker was completed detached all the way around.

 

[oplitic]

Yes, Everything is stock. I am not adding anything to the system, just replacing a tired woofer. If the polarity is not an issue, why would the connectors coming from the amp (or wherever its coming from) to the woofer be different in size? The connector on one wire is almost twice the size of the other wire connector.

I will switch the wires today and remount to determine if my aging ears can tell any difference.

BTW, the original woofer was in bad shape when I removed it. The foam that connects the circumfrance of the paper to the metal frame of the speaker was completed detached all the way around.

I don't know why the wires would have been different sizes. Speaker wires are always the same siz when you buy them, and should be the same size, the return path should be tha same as the wires going into it. Just like power wires (pos and neg to the amp).

 

[awhughes]

I also wanted to mention that the replacement woofer I have installed is 8ohm. Is this correct for the stock JBL system?

 

[scucci]

The EBSCO website schematic shows black/light green as positive and black/white as negative.

Scucci

 

[awhughes]

The EBSCO website schematic shows black/light green as positive and black/white as negative.

Scucci

Confirmed: both wire configurations Scussi describes above exist and produces the desired thump. Now I am getting my usual earfull from the stock JBL system. 182K miles and sounds like a new one. Now I dont hear the front end creaking.

BTW the larger wire connector is on the negative wire (black/white).

Thanks, Scussi for your perserverence on this thread.