Most speakers are either 4-ohm, 6-ohm, 8-ohm or 16-ohm speakers. Ohms are a measure of impedance, which represents the amount of power the speaker draws. Impedance is equal to voltage divided by current. This means that a 4-ohm speaker draws more current than a 6-ohm speaker; more current gives it more power and usually enables it to play loudly more easily. If you connect 4-ohm speakers to an amplifier that can only drive 6-ohm speakers, the speakers will draw too much current and the amplifier will probably overheat and shut itself off. You can measure the impedance of a speaker with a multimeter. Tips Warnings Writer Bio
