How can i test speaker wire outlets to see if wires are crossed ?

Question

I have rear speaker outlets in the rear of my living room. They were put there by using a product called flatwire to run under the floor boards. I do not know if the flatwire was installed properly so I want to be able to test whether or not the speaker wires are labeled properly as left and right and also whether they might be crossed (shorted). I'd like to do this without running them to the receiver first, since the instructions for that warn that this could cause harm to the receiver.

Any good ideas on testing this?

Thanks.

Answer 1

If you have a voltmeter, connect a AA or AAA battery on one end and measure the voltage (and polarity) at the other end. Do the same for each cable. Mark each cable and polarity.

If you don't have a voltmeter, use a speaker, the cone will displace to one side or if the polarity is reverse, will displace the other way.

Answer 2

I definitely suggest investing in a digital multi-meter.  Get something that allows you to check volts as well as continuity or resistance in ohms.  

The first step is to set the meter to continuity.  Make sure the wires at one end are not touching.  Connect the probes of the meter, one to each wire on the other side.  If you read any continuity, there is a short in the wire.  If the meter doesn't have a continuity function you can use the resistance function.  Set the meter to the lowest range or just ohms (Ω) if it is auto ranging.  Repeat the same procedure as before.  You should have a reading of infinite resistance (the same reading the meter would show with the leads touching nothing.)  If you show some reading, there is a short. (Note: Don't touch the probe ends or wires during these tests or the meter might be reading resistance through your body)

There are a couple ways to test for polarity.  I like the battery idea posted.  Take the battery and connect it to one side of the speaker wire (one lead to the suspected positive end and the other to negative.) Set your meter up for DC voltage and probe the wires at the other end.  A negative sign will come up on the reading if you have the negative probe touching the positive wire.  I also like the idea of watching the speaker movement as you apply a small DC voltage.  To accomplish this, connect a speaker to one end of the wire.  Then, at the other side, hold the suspected positive end to the positive end of the battery and tap the negative to the negative side of the battery. Observe the movement of the speaker cone during this action.  If the cone moves out then in, the polarity is correct.  If it moves in first then out, the polarity is reversed.  Good luck.

Answer 3

This trick is used by car-audio installers to check which speaker is left and which is right.

Just connect the speaker wires to a 1.5V battery. If everything is OK, you should hear a beep!

Answer 4

put full base on see if the cones are breathing out instead of in on the boboom if in crossed

Answer 5

contiguity tester