Speaker Wire In Walls, no noticable difference in +/-

[rthune101]

Ok so I go to a friends house to help him hook his system up, he has 14g in wall speaker wire buried, I cut holes in his sheetrock, I pull the wires out and there is no noticeable black stripe or an markings to decifer the +/-. Anyone have any good/qucik ideas on how to determine which is which?

[J6P]

Sometimes they do it with ridges on one side of the insulation. Did you notice a "smooth" side and a "rough" side? It can be a very subtle difference, you really have to inspect closely.

[mr peepers]

there is always one thing to help decipher which strand is which.

some common ones are:

different color sheathing wrapped around each wire. ex: red/black
one wire sheathing has a line or dashed line running along the length of it.
sometimes even the copper wire itself can be of a different shade.
there may be the speaker manufacturer's brand name written on one sheath across the entire length of the wire.

sometimes it can be rather minute and inconspicuous, but there is most definitely something there to differentiate which wire is which.

maybe take a pic of the speaker wire.

[matthewrounds]

If there is a way to discern between the two wires, you only need to be consistent with how you connect the cable to the receiver and speaker. I hope this make sense that the wires are neither +/-, the wires are just wires.

[Rob71]

Originally Posted by rthune101

Ok so I go to a friends house to help him hook his system up, he has 14g in wall speaker wire buried, I cut holes in his sheetrock, I pull the wires out and there is no noticeable black stripe or an markings to decifer the +/-. Anyone have any good/qucik ideas on how to determine which is which?

Do you have access to a multitester? If all else fails you can use it to check continuity.

[rthune101]

I dont know what kind of cheap sh*t this is, but they are 35' runs already buried in the finished wall. There is absolutely no difference in the speaker wire jacket, or wire for that matter. Absolutely no markings what-so-ever, I bet it's Monster....LOL!!!!! Anyway I dont have a Multitester, but looking for any other ideas you guys might have.

[Grevlin]

Another long piece of cheap wire (one strand) + Little light bulb + battery

Hook a up a long circuit between both ends of in-wall wire. When the bulb lights up - label the ends.



:MacGyver theme song playing in background:

[naturephoto1]

Originally Posted by Grevlin

Another long piece of cheap wire (one strand) + Little light bulb + battery

Hook a up a long circuit between both ends of in-wall wire. When the bulb lights up - label the ends.



:MacGyver theme song playing in background:

http://www.youtube.com/watch?v=3w-oDZSLUrY



Rich

[rthune101]

See now that is why I come here, you guys flat our rule!!!!!

I think I will also throw in some duct tape for good McGuyver measure!

Thanks again, this really helps....and I am going to kick his contractor in the throat for using such carp!

[VinnAY]

assuming that your friend wanted to go with a better cable, higher gauge, whatever, and both ends of the wire are accessible, you could simply tape one end and then pull the other.
That sounds way too easy but it could be that easy dependant upon how the wire was actually routed.

[Beta Man]

Originally Posted by VinnAY

assuming that your friend wanted to go with a better cable, higher gauge, whatever, and both ends of the wire are accessible, you could simply tape one end and then pull the other.
That sounds way too easy but it could be that easy dependant upon how the wire was actually routed.

I'd put some Duct tape SECURELY.... if you get snagged up on something etc... you don't want to break it off mid-way, and then be stuck with no in-wall wiring..... but this method is certainly worth a shot.... and you could even run a couple new wires at the same time.

[Rob71]

Originally Posted by Grevlin

Another long piece of cheap wire (one strand) + Little light bulb + battery

Hook a up a long circuit between both ends of in-wall wire. When the bulb lights up - label the ends.



:MacGyver theme song playing in background:

A MacGyver continuity tester... I like it. And naturephoto1, thanks for the theme. With all the oddball schemes I come up with I need to put that on my MP3 player and set it to loop.

[ansat]

Not quite as macgyvresk but a tester and a 9v battery works well. You can hook it up and look at weather or not it reads 9v or -9 if -9 then you know that your backwards on your multimeter. and really you dont need a 9v. you can use any battery (I just find the 9v the easiest to rig up to hold the wire.

[zicmubleu]

Originally Posted by Grevlin

Another long piece of cheap wire (one strand) + Little light bulb + battery

Hook a up a long circuit between both ends of in-wall wire. When the bulb lights up - label the ends.



:MacGyver theme song playing in background:

You could use the speaker instead of a lightbulb. Hook up one lead to the speaker and the other speaker connection to your "long circuit" or ground, connect the battery either to the "long circuit" mentioned above or ground and then scrape the lead to be tested on the battery. When you hear the crackle from the speaker you have identified that lead. Using a ground point such as house wiring ground carries the risk that it might not be ground, but that should not be much of a risk unless you have noticed some funny things about your house powering. Realistically, every audiophile should have a multimeter, a cheap one works fine for 95% of its uses. Then your friend will think you are a pro too!

[ansat]

Originally Posted by zicmubleu

You could use the speaker instead of a lightbulb. Hook up one lead to the speaker and the other speaker connection to your "long circuit" or ground, connect the battery either to the "long circuit" mentioned above or ground and then scrape the lead to be tested on the battery. When you hear the crackle from the speaker you have identified that lead. Using a ground point such as house wiring ground carries the risk that it might not be ground, but that should not be much of a risk unless you have noticed some funny things about your house powering. Realistically, every audiophile should have a multimeter, a cheap one works fine for 95% of its uses. Then your friend will think you are a pro too!

I will agree that you should have one... however a cheap meter usually gives the same information as a expensive one. the expensive one however has better safety features. I am not advocation spending a 100 dollars on a meter but I would stay away from the 10 - 15$ meters and find something in the 20+ range with at least 2 fuses. That would allow you to safely test anything in your car or home.

[Jacobisthe]

Well, if you have a speaker and a batter, hook the speaker up like you normal would, then touch the other two ends to the battery. If the cone goes out when you touch the battery to the one end of the wire, the wire touching positive on the battery is positive. If the cone goes in then the positive on the batter is touching the negative on wire.

[rthune101]

Problem solved with battery and another wire. His contractor stapled the wires to the studs inside the walls, so swapping it out with some duct tape and a quick tug will not suffice. He also ran HDMI for his projector, no conduit.....man why are some people like this out there? LOL

[DiverSpear]

Originally Posted by rthune101

Problem solved with battery and another wire. His contractor stapled the wires to the studs inside the walls, so swapping it out with some duct tape and a quick tug will not suffice. He also ran HDMI for his projector, no conduit.....man why are some people like this out there? LOL

The wires are required to stapled to the wall per NEC, and conduit not required for HDMI as long as it is CL2 or better. Before you call a contractor out, make sure you know the code.

[kaputsport]

I am surprised no one knows the 9 volt trick.

Hook up the speaker end to the speaker, and then touch the wires to the 9 volt... If the speaker jumps out, then you have correct polarity, if it does in, you are reverse.

Warning: Do not hold the wire on there long, as you are creating a square wave esque feeling on the voicecoil and you will blow your speakers.

[cojake]

The battery trick works great. I would use a D or an AA battery though. It is a little safer to put 1.5 volts vs 9 volts across the speakers voicecoil. I used this method when I worked in a Car Stereo installation shop. We would do insurance work where the wires would be all cut and could figure out which speakers were which and the correct polarity of each.