Music signal time reverse effect apparatus

Apparatus for converting an input note signal of the type having a rapid rise and a slow exponential decay into an output note signal which, from the shape of its envelope, appears to be a time reversed version of the input note signal includes a device which forms a normalized envelope signal, En, and a gain modification device which modifies the instantaneous gain applied to the note signal as a function of the instantaneous amplitude of En. Ideally, the function is proportional to the inverse of the square of the instantaneous amplitude of the normalized envelope signal, En. The gain modification device in accordance with a first embodiment includes an analog-to-digital converter fed by En which addresses a ROM lookup table containing data words corresponding to gain amplitudes. In a second embodiment of the gain modification device, the dynamic range of En is divided into regions and current sources are selected for charging a capacitor depending on in which region the instantaneous amplitude of En lies, to select in each region a slope versus time of the instantaneous gain.