A centrally controlled voice synthesizer includes a memory which is preprogrammed with voice data, melody data, address data, and control data, an input processor for receiving an external signal and outputting a triggering signal, a clock generator for generating clock signals; a control logic unit receiving the clock signal from the clock generator, being triggered by the triggering signal from the input processor thus fetching the voice data, the melody data, the address data, and the control data from the memory, a decoder decodes the data fetched from the memory via the logic control unit and generates a control signal, a rhythm generator for outputting a rhythm signal to the logic control unit upon receiving the clock signal from the clock generator and the control signal from the decoder, a digital-to-analog converter connected to the memory and converts digital voice data from the memory to analog voice signal, a transistor connected to the digital-to-analog converter for amplifying the analog voice signal and driving an external speaker to emit corresponding voice duplication.