Wiring – Identifying positive and negative speaker wires

speakerswiring

My house came with 2 wall speakers. There is wiring for both of them. The right and left speakers have 2 wires each.

I'm trying to hook them up to my amp but I have no idea which wire is positive or negative.

  • They are both copper
  • Neither wire has a stripe
  • The insulation for both wires is the same color (gray)
  • There is no + or – indicator on the insulation

I'm at a loss. I also tried hooking up one speaker and then swapping the wires to see if the sound quality was noticeably different one way or the other. I honestly can't tell, it sounds good either way.

enter image description here

Sorry it's blurry but as you can see the wiring is identical. The insulation as Ecnerwal mentions in his answer is different – one is smooth and one ridged.

Best Answer

Look closer at the insulation - there's nearly always a physical clue, such as tiny ridges on one wire, not on the other.