Play system and its play method

The playing system includes audio processor, power amplifier, and automatic equalizer. The audio processor converts music melody into the output of original audio signal (OAS). Being coupled to a loudspeaker unit, power amplifier is in use for amplifying OAS into original signal intensity at different frequency bands. Being coupled to power amplifier, after receiving amplified OAS, automatic equalizer generates original signal intensity for amplified OAS at different frequency band. Analyzing original signal intensity, the audio processor is in use for determining music type of music melody. Based on curve of equalizer corresponding to music type, audio processor generates audio signal after first adjustment. Through power amplifier, the audio signal after first adjustment is transferred to loudspeaker unit for playing.