Abstract: A source of monaural sound such as a radio receiver or record player provides an audio signal which is fed along parallel paths to a like number of speakers. In one or more paths there is a control which imparts amplification or gain to the signal. In the other path, however, a frequency dependent amplitude variation and phase delay means is interposed in the circuit. It is the purpose of this means to vary the amplitude response of that signal to introduce a bass boost of about a factor of two and a treble cut of about a factor of ten and to vary the phase shift of that signal to introduce from about a 180.degree. to about 225.degree. phase lag to the monaural signal, the amplitude response and phase lag being a function of the frequency of the signal, to impart a simulated stereo effect to the sound as heard from the plurality of speakers.