All receivers and speakers have a positive (+) and a negative (-) terminal (or connector) on the back for connecting wires. The positive terminal is usually red and the negative is typically black. (Note: speakers that are bi-wire capable will have four connectors, two red and two black). Speaker wires and connectors are usually marked with a + or – and some are color coded for easy identification. If not, identify the + and – on the wires with a piece of tape or a permanent marker.
The speaker wires must be connected correctly on both the receiver and speaker. For example, the positive speaker terminal (red) on the receiver must be connected to the positive terminal on the speaker and the negative terminal (black) on the receiver connected to the negative terminal on the speaker. When connected this way, the speakers are said to be 'in-phase', which means both speakers are operating the same way. If one of these connections is reversed (ie. positive to negative instead of positive to positive) the speakers are 'out of phase', which can cause serious sound quality problems. It won't damage any components, but you can probably hear the difference.
The quickest way to ensure the right connections is to do a visual inspection of your system, following the wires from the receiver to the speakers. However, keen ears can also hear the problems created by a system where the speakers are wired out of phase. Here's what to listen for:
- Very thin, lean-sounding bass
- No discernable center image
- A general feeling that the system just doesn't sound right
Of course, other system issues can create these problems, but incorrect speaker phase is one of the most common mistakes made when connecting a stereo system. It's easy to do when you're dealing with a clutter of audio and video cables. It's worth the time to make sure all speakers are in-phase. Remember: positive-to-positive or red-to-red and negative-to-negative or black-to-black on both the receiver and speakers. Good listening!