Abstract: In an electronic musical instrument of the type having keys, a system for controlling the volume of the sound produced by the instrument when the keys are depressed or struck. For each key, the system comprises a tone generator, a gate coupled between the tone generator and the speaker of the instrument; and control means for producing a control signal having an amplitude which is a function of the speed at which its associated key is moved while being depressed. The control signal is applied to the gate to pass the output of the tone generator to the speaker and to control the volume of the sound produced by the speaker.