The power consumption of audio power amplifier is discontinuous. Theoretically, the power provided is only half of the maximum power of the amplifier. For example, a 2X400W power amplifier and a 400W transformer are enough. The larger the filter capacitor, the better. The filter capacitance of 8 Ω horn should be above 10mF, and that of 4 Ω horn should be above 40mF.