Power amplifies are provided to correspond with a plurality of speaker units constituting a speaker array. Driving signals from the power amplifies are supplied to one terminals of the speaker units, and other terminals are connected a common line. Inverters are provided at preceding stages of the power amplifies such that the driving signals supplied to the speaker units being arranged adjacently have an opposite phase respectively. Since a correlation between the driving signals of the adjacent speaker units is high, a current flowing through the common line can be very reduced. An LED display panel can be driven by the similar method.