Abstract: A system and a method of electronically equalizing the composite transfer function of a sound system and a room which receives the sound generated by the sound system. A test signal, such as white or pink noise, is applied to the sound system and a microphone for receiving the reference sound is placed in the room and has its output applied to an equalizer which comprises a plurality of contiguous narrow band filters covering the entire audio band. Each output signal from the filters is applied through an adjustable amplitude control means to a detector and each detected output signal is compared with a reference signal, such as the detected output signal from a selected mid-range filter and has its amplitude adjusted to provide a desired relationship with respect to the reference signal. After adjustment of the equalizer, the test signal and the microphone are disconnected from the system and the sound signal source is applied through the equalizer to the loudspeaker system.