In this video we explain that although speaker impedance is usually specified, as a 4, 8, 16 Ohm nominal value, in reality the impedance of the speaker changes over frequency. We characterize a Fender Champion 600 speaker, measuring the speakers impedance from 10Hz to 3kHz. We also show the relationship between impedance and resonance. Finally we prove that resistive loading impacts the operation of the amplifier power amps stage much differently than a reactive load. #tubeamplifier #guitar #electricguitar #speaker #fenderamps