Abstract: A method and apparatus are described for electronically processing sound. An electrical signal derived from audio information is split up into two separate signal paths. The signal travelling along one path is passed through an exciter circuit and an attenuator and is then combined with the signal travelling along the other path. In one embodiment of the invention the signals travelling along the two paths are combined electronically and in another embodiment of the invention the two signals are combined acoustically. The exciter circuit is made up basically of a high pass filter and a harmonic creator. The harmonic creator is designed to create low order, odd and even harmonics of frequencies whose amplitudes are above a preselected threshold level. Two versions of the exciter circuit are disclosed, one containing vacuum tubes and the other solid state. The quality and various other characteristics of sound that is processed according to this invention are believed to be greatly enhanced.