A combination equalizer and calibrator circuit assembly includes a calibrator formed of a frequency control circuit, a signal generator, an amplifier circuit connected with a microphone, a compare circuit and a display circuit and connected to the front end of an equalizer set. Calibration is made through the calibrator prior to audio system reproduction, wherein the frequency control circuit provides a reference frequency and different test frequencies for causing the signal generator to generate respective sound signals for output through a speaker; the microphone picks up these sound signals for comparison with respective reference values by the compare circuit; and the display circuit displays the respective comparison results. By means of adjustment through respective adjust circuits, signals of test frequencies are standardized so that the music played through the audio system is well calibrated without sound spectrum distortion due to space or audio system discrepancy.