After the run of the "MyEqualizer.m" file a graphical user interface appear. By pressing the "Load" we can load audio signal (type .wmv). After we can model the frequency behavior of the FIR filter that is used to filter that signal. After we can listen the filtred audio signal by pressing the "Play " button. In the GUI M-file I m using three importanat function: [ ]=coeff() that generate cell contain the coefficient of the equalizer, equalizer_plot() who plot the frequency behavior of equalizer and the equalizer_play who filter and play the filtered audio signal.