Abstract: An apparatus for the representation of the sound of the human voice as an image in which individual colors correspond to distinct loudness levels. Sound received by a transducer is converted into electric signals, amplified, processed and transmitted to light emitting diodes which are arrayed in groups according to the color of the light they are emitting. Different groups are programmed to emit light when they are energized by signals reflecting different loudness levels. The display in which the colors change as the loudness varies provides a continuous feedback in real time by showing a speaker instantaneously how loud he speaks.