Why are speakers labeled + and – or Red and Black?
Speakers make sound my pushing and pulling at the air with the motion of their cones or diaphrams. When a positive voltage is applied to the red or “+” terminal on a standard speaker, it causes the cone to move outwards and push air. If you have two speakers side by side and one cone moves out while the other moves in, air will move between the two speakers but not much sound will escape. The two cone motions will cancel each other. So when you have two speakers close together, it is vital that they be wired “in phase”, with positive voltage going to the “+” terminal of both speakers at once. You can do this by wiring the speakers in parallel or series. In almost all cases, parallel is preferred. If wiring speakers in parallel, the “+” output should go to both “+” terminals and the “-” output should go to both “-” terminals. If wiring speakers in series, the “+” output should go to one “+” terminal. The other terminal (“-“) should go to the second speaker “+” terminal. The other termin
