Many of the speakers in our residential have an additional pin on the termination panel for the purposes of earthing the loudspeaker. This is not essential, however, if you have the ability to use this terminal then we recommend that you do so.
A loudspeaker works on the principle of a coil of copper wire moving within a magnet. Coils of copper wires tend to pick up radio waves and other interference which will in turn be amplified through your loudspeaker. Earthing or grounding the speaker helps to eliminate this.
Many hi-fi and home theatre amplifiers will have a designated grounding pin, however, if you have an amplifier without a grounding pin and still wish to use this feature then you can run a length of cable from the earthing pin on the loudspeaker and connect it to one of the screws holding the amplifier chassis in place as this will have the same effect.