Speaker impedance is a measure of the resistance that a speaker presents to an electrical signal. It is typically measured in ohms (). The impedance of a speaker is important because it affects the amount of power that the speaker can handle and the sound quality that it produces.
The impedance of a speaker is not constant, but varies with frequency. The impedance of a speaker is typically highest at its resonant frequency, which is the frequency at which the speaker cone resonates most easily. The impedance of a speaker can also be affected by the temperature of the speaker and the amount of power that is being applied to it.