Identifying Which Wire Pair Goes to Which Speaker?

[JoLin]

Hi- There are 4 speakers installed in my boat. There are 4 clear/white and 4 clear/black wires in the stereo location, that terminate in a common block.

I assume that I'm looking at the + and - wires for each of the speakers.

Question- how can I determine which wires run to which speaker? I can't physically trace the wire runs. I have a digital multi-meter, but not sure if I can (or how to) use it for this purpose.

Any advice?

 

[bruceb58]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Just get a 9 volt battery and touch the pairs to the battery quickly while someone listens to the speakers. The one that makes a pop noise when you touch the wires belongs to that speaker.

If you have to determine which wires are pairs, you put one white wire on the battery and then run through the blacks alternating which one touches the battery until you find the one that causes a noise. Repeat for the rest of the wires. You can also use your ohm meter to determine the pairs but it won't help you find which speaker they go to.

 

[JoLin]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Very clear. Thank you!

If I wanted to first match up the pairs, how would I use DVM?

You mentioned using the ohmmeter. In this case, would I set the unit to the ohms scale, then put the black lead on one of the blacks, and run the red lead through the whites, until the reading changes?

Do I assume correctly that the reading would drop from infinite to something lower when I find a matched pair?

I appreciate the advice.

 

[bruceb58]

Re: Identifying Which Wire Pair Goes to Which Speaker?

You mentioned using the ohmmeter. In this case, would I set the unit to the ohms scale, then put the black lead on one of the blacks, and run the red lead through the whites, until the reading changes?

Correct. Put your meter at its lowest ohm scale. Should read close to 0 ohms or single digits. It will be obvious. You have to do the battery trick to determine which speaker unless you want to take each speaker off.

 

[JoLin]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Perfect. This way, I can match up pairs before I need to use the battery trick (and a helper). Can probably then listen by myself for the 2 forward speakers. They're only about 8 feet from the wire termination block.

It's tough to get a helper, and they're always in a hurry

I'll report back when I get a chance to do this. Hopefully this week.

Thanks again.

 

[mnmike3]

Re: Identifying Which Wire Pair Goes to Which Speaker?

the 9V battery trick works great and can also be used to check the polarity of the wires. this important because if you wire the speakers out of phase (+ and - backwards) it more than likely will effect bass output from the speakers.

when you touch the speaker wires to the 9v look to see which way the speaker moves. If the cone moves out towards you then which ever wire you touched to the + side of the 9v is your + speaker wire. if the cone moves in you have the speaker wires backwards.

you can wire all the speakers 180 degrees out of phase (all 4 + and - backwards but the same as eachother) and probably won't be able to tell a difference but if you get 1 speaker out of phase with the others it will effect how it sounds.

To simplify it down you want to make sure your + and - wires are correct on all speakers so they will sound the best they can and using the 9v will help you make sure its wired right

 

[RickJ6956]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Make sure you only touch that 9v to the wires by swiping the contacts. Leaving them connected for any length of time can damage the voice coils.

Another way to test is to use the headphone output of an ipod or other portable music player/radio. Use a 3.5mm to RCA breakout cable and alligator clips.

 

[JoLin]

Re: Identifying Which Wire Pair Goes to Which Speaker?

SUCCESS!!

Bruce, everything worked like a charm. Used the ohmmeter to segregate the speaker wire pairs, then tried the 9V battery trick. I was in the cabin as I touched the leads to each pair. The 'POP' was loud and clear- I had no problem identifying all 4 speakers, including the 2 back in the cockpit.

A funny thing happened when I used the ohmmeter. As I zeroed in on each pair, I saw readings of 3.8, 4.1, 3.9... along about the third one, some tired old synapse in my brain fired off and I realized, "Well, DUH! 12V stereo systems usually use 4-ohm speakers!"

I guess when you haven't done something in about 30 years, the old knowledge gets a little 'rusty'

Anyway, mission accomplished. Stereo wired up, installed and working.

Thanks!

 

[bruceb58]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Glad everything worked out.

 

[RickJ6956]

Re: Identifying Which Wire Pair Goes to Which Speaker?

As I zeroed in on each pair, I saw readings of 3.8, 4.1, 3.9... along about the third one, some tired old synapse in my brain fired off and I realized, "Well, DUH! 12V stereo systems usually use 4-ohm speakers!"

For the record, not all speakers will show their AC impedance when you read DC resistance with a multimeter. Many 8-ohm rated pro concert speakers, for example, read around 6 ohms DC resistance. What you're really doing with a mm is making sure the voice coil is neither open nor shorted.

You need an impedance meter to accurately measure AC speaker impedance. At nearly $300, not many DIYers buy them.

 

[JoLin]

Re: Identifying Which Wire Pair Goes to Which Speaker?

For the record, not all speakers will show their AC impedance when you read DC resistance with a multimeter. Many 8-ohm rated pro concert speakers, for example, read around 6 ohms DC resistance. What you're really doing with a mm is making sure the voice coil is neither open nor shorted.

You need an impedance meter to accurately measure AC speaker impedance. At nearly $300, not many DIYers buy them.

Thanks for the clarification. Guess I was making a false correlation there.

 

[bruceb58]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Of course it didn't really matter for what you were doing.

 

[DennisM]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Of course it didn't really matter for what you were doing.

Simple way to trace them.

Disconnect each set at the radio, and then at the four speaker locations. Once you have just the wires open, pick up a tone generator from the local BORG, connect the sending side to radio side of wires, and then probe the speaker location wires with receiver until you hear the tone.

Mark wires and done..

 

[bruceb58]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Dennis,

You are a little late on this. I do have a question. What is a BORG?

 

[DennisM]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Big Ole Retail Giant.

Its a acronym we use on another forum, to avoid saying names like Menards, home depot etc..

 

[JoLin]

Re: Identifying Which Wire Pair Goes to Which Speaker?

Thanks, Dennis, but all I needed was a 9-volt battery and 2 hunks of wire...

 

[RickJ6956]

Re: Identifying Which Wire Pair Goes to Which Speaker?

The toner alone would work to drive the speakers loud enough to hear them. No need for the induction wand, and no need to remove the speakers. Besides -- again -- not many DIYers would spend the $125+ for the toner kit.

It is the way I do it, though, when identifying telephone pairs or distributed speaker lines.